From ard@siva.bris.ac.uk Mon Mar 21 10:39:53 1994 Received: from siva.bris.ac.uk by nfs1.digex.net with SMTP id AA11027 (5.67a8/IDA-1.5 for ); Mon, 21 Mar 1994 10:33:51 -0500 Received: by siva.bris.ac.uk (MX V3.3 VAX) id 3177; Mon, 21 Mar 1994 15:35:53 GMT Date: Mon, 21 Mar 1994 15:35:49 GMT From: "PDP11 Hacker ....." To: rdd@access.digex.net Message-Id: <0097BC58.6F6095B6.3177@siva.bris.ac.uk> Subject: ftp site : hardware FAQ Status: RO PERQ 2 HARDWARE FAQ LIST ------------------------ The following questions are answered on this list General ------- What models of PERQ 2 existed, and what are the differences? How do I open up a PERQ 2? What are all the circuit boards for? Is there a colour code for the handles in the card cage? Are there any custom chips in a PERQ 2? What are the pinouts of the I/O ports? What sort of hardware expansions are possible? What are the I/O port addresses? What do the DDS numbers mean? What are ICL-coded chips? CPU --- Can you give an overview of CPU operation? What is the format of the microcode word? What are the commands for the microcode sequencer? What is a short jump, long jump, leap? What is the Raster-op machine? How does the CPU do input-output operations? Can I modify a 24 bit CPU into a 20 bit CPU? How about the other way? How do I debug a WCS failure What are the edge connectors on the front of the CPU board? Mem --- What memory boards existed? Can I increase the size of my memory board? Can I use a landscape board with a portrait monitor, or vice-versa? What are the useful links on the memory board for? What is the trim-pot on the front of the memory board for? EIO --- What are the main sections of the EIO board? What is an NIO board? There are 4 serial channels. What are they used for? How is the sound produced? Where is the ethernet address stored? How do I set the links for different types of hard disk? OIO --- What is an OIO board? What versions of OIO existed? What sort of Laser printer do I need? What are the PERQLink connectors for, and what are the pinouts? What other boards went in the OIO slot? Can I add tape streamer support to an OIO board? What sort of tape streamers were supported? Is there any reason why the PERQlink connectors are similar to the DEC DR11? Monitors -------- Safety precautions. What are the scan rates of a PERQ monitor? How do I open up a monitor? What are the presets in the monitor? What do I do if the hybrids in my T1 monitor fail? My landscape monitor flickered a bit, and went blank. Help! What's the EHT unit in a landscape monitor? Keyboard/Mouse -------------- What are the interfaces on the keyboard/mouse? How do I open up the mouse and tablet, and what's inside? What are the custom chips in the keyboard? Disks ----- How do I clean the floppy disk heads? What is a DIB? Can I add a 2nd floppy drive? How about a second hard drive? What are the pinouts of the 8" floppy drive? Can I use a 5.25" Floppy drive? Does double-density operation work? Power supplies -------------- Safety precautions Are the PSU's the same between different models? What are the ratings of the PERQ 2 PSUs What voltages can I get from the outputs on the back of the PERQ? What are the fuses on in the PERQ 2 psu? How do I open up the PSU? What normally fails in the PSU? --------------------------------------------------------------------- And so, On with the Questions --------------------------------------------------------------------- General ------- What models of PERQ 2 existed, and what are the differences? There were 3 different PERQ 2's : T1 - 20 bit CPU with 16K WCS, 8" micropolis hard disk, often 1M RAM and portrait monitor. This machine (aka ICL 8222) was distributed by the SERC in the UK to many UK universities, and is relatively common in the UK T2 - Basically a T1 with a 5.25" ST506 hard disk. 1M or 2M RAM, portrait or landscape monitor. This machine (aka ICL 8223) is probably the most common PERQ T4 - A 24 bit CPU, giving 24 bit addressing, although only 4Meg memory boards existed. This machine is very rare (about 10 were made). ----- How do I open up a PERQ 2? It's easy. The screws on the bottom edge of the front and sides retain those panels, which can then be removed. Removing the front and left side panel allows access to the card cage (remove the boards by pulling the handles), the PSU (remove it by unplugging the 4 connectors at the back, removing the 2 screws at the front edge, and sliding it out), and the floppy drive (unplug the 3 cables, remove 3 fixing screws (2 at the front, 1 at the rear), and slide it out). To remove the hard disk, it's best to remove the 6 large screws holding the top half of the back panel, carefully swing it out, and disconnect the cables. ----- What are all the circuit boards for? In the card cage, there are 5 slots. From the left, they are : 1) CPU option (empty) 2) CPU board 3) Memory board (also video circuitry) 4) EIO (input/output) 5) OIO (optional Input/output). The other boards in the case are DDS (Digital Diagnostic system) - top right above card cage, with 7 segment displays - displays hardware error codes. Disk adaptor (DIB) - mounted on the hard disk. Floppy disk board - on the drive itself. Power supplies ----- Is there a colour code for the handles in the card cage? Yes. The code is : CPU option - Blue CPU - White Memory - Green EIO - Red OIO - Yellow Some cabinets have a coloured label under the card cage which gives this information. Also, the boards will not fit in the wrong slots. ----- Are there any custom chips in a PERQ 2? There are many proms and PALs on all boards of the PERQ 2, but none of these are copy-protected, so backups can be made for personal use. The same applies to the EPROM in the keyboard, and the microcontroller in the tablet. The real custom chips are the floppy disk read amplifier (on the shugart 851 disk drive), the keyboard drive/sense chips (in the keyboard itself), and hybrid circuits in the KME T1 monitor. ----- What are the pinouts of the I/O ports? The RS232 ports are wired as DTE's and the following pins are used : 1 - Gnd, 2 - TxD, 3 - RxD, 4 - RTS, 5 - CTS, 7 - Gnd, 8 - DCD, 15 - TxC in 17 - RxC, 20 - DTR, 24 - TxC out The GPIB bus is silly. The pins of the 25 pin D-connector on the PERQ have to be wired to the same _numbered_ pins of the amphenol plug , pin 25 is not used. So, you can't use a simple IDC cable. The pinout is : 1 - D1, 2 - D2, 3 - D3, 4 - D4, 5 - EOI, 6 - DAV, 7 - NRFD, 8 - NDAC, 9 - IFC, 10 - SRQ, 11 - ATN, 12 - Gnd, 13 - D5, 14 - D6, 15 - D7, 16 - D8, 17 - REN 18-24 - Gnd The ethernet ports are standard - 1 - Gnd, 2 - Coll+, 3 - Tx+, 5 - Rx+, 6 - Gnd, 9 - Coll-, 10 - Tx-, 12 - Rx- 13 - +12V The Display D-connector seems to have the following pinout, but check pins 8 and 15, which are swapped on some machines! - 1 - +12V, 2 - Speaker audio, 3 - Gnd, 4 - Hsync, 5 - Gnd, 6 - Vsync, 7 - Gnd, 8 - Tablet Data, 9 - Tablet Clock, 10 - Gnd, 11 - N/C (loop?), 12 - NC (Land L) 13 - Keyboard Data, 14 - Gnd, 15 - +5V The Display BNC carries the video data on it's centre pin. The Laser Printer connector is for a Canon CX direct engine, and carries the following signals : 1 - Dot +, 3 - Clock, 4 - Status, 5 - Print, 6 - Status Request, 7 - PFSP, 8 - Rdy, 9 - PRND, 10 - Top, 12 - Bd sync+, 13 - Dot-, 15-22 - Gnd, 23-24 - Bd Sync - The pins on the circuit boards are numbered from 1(top) to 100 on the component side, and 101-200 on the track side. For I/O expansion, the useful pins are the same on the OIO and CPU option slots and are : 156 - IOD15, 56 - IOD14, 157 - IOD13, 57 - IOD12, 158 - IOD11, 58 IOD10, 159 - IOD9, 59 - IOD8, 161 - IOD7, 61 - IOD6, 162 - IOD5, 62 - IOD4, 163 - IOD3, 63 - IOD2, 164 - IOD1, 64 - IOD0, 166 - IOA7, 66 - IOA6, 167 - IOA5, 67 - IOA4, 168 - IOA3, 68 - IOA2, 169 - IOA1, 69 - IOA0, 71 - IO Enable L IOD = IO Data, IOA = I/O address, and IOA7 is a read/write line. Pins 50,150,51,151,52,152 are +5V. Other pins ending in 0 or 5 seem to be ground, but check with an DMM. ----- What sort of hardware expansions are possible? Almost anything. There are enough spare I/O addresses to allow quite a number of extra I/O ports on a board placed in the CPU option slot. Some suggestions include SCSI, I2C, more serial ports, MIDI, and more. If you don't want to mess about inside the PERQ, you can use the GPIB as an expansion bus. Also, the perq-link connectors on the OIO board are a 16-bit parallel I/O port. ----- What are the I/O port addresses? Here are all the I/O port addresses that are known, with bit definitions where apropriate. Note that there is some ambiguity about the sense (active high or low) of the port address lines, and most PERQ software in fact uses an iverted high bit from that given here, which represents the hardware Octal Hex Function EIO card : 134:136 5C:5E Load usec clock 130:132 58:5A Load Bit Counter 124:127 54:57 Load DMA Address 336:337 DE:DF Read usec clock 332:333 DA:DB Read Bit Counter 105 45 Load Interrupt Enable Bit Meaning 3 External Address 2 Not Reset 1 Microprocessor Ready Interrupt Enable 0 Microprocessor Interrupt Enable (to PERQ) 104 44 Load uproc data 103 43 Load Net Enable Bit Meaning 0 Enable Network Interrupt 102 42 Load Net Control Bit Meaning 8 Go 6 Receive All 5 Not Reset Net 4 Transmit 3 Enable bit count 2 Enable usec clock 1 Enable usec interrupt 101 41 Load FP Inst (Not implemented) 100 40 Load DMA Channel 110:117 48:4F Load Net File 325 D5 Read uproc status Bit Meaning 15 Micro IOD out ready 7 Micro Ready 324 D4 Read uproc data 323 D3 Read disk status Bit Meaning 10 Drive type bit 1} 11=8"micropolis, 10=14" 9 Drive type bit 0} Shugart, 00=5.25" All types 8 Index/2 7 Drive unit ready 6 Seek complete 5 Drive (write) fault 4 Seek Error/Track 0 (depends on drive type) 3:0 Disk controller status? 322 D2 Read net status Bit Meaning 7 Carrier sensed 6 PIP???? 5 usec clock overflow 4:0 Net controller status 321 D1 Read FP Result (Not implemented) 320 D0 Read FP status (Not implemented) 123 53 Load disk control 2 Bit Meaning 7 Drive select 0/DIB address 0 6 Drive select 1/DIB address 1 5 BA0/Dir/Data5 4 BA1/Fault Clr/Data4 3:0 Data3:Data0 122 52 Load disk control 1 Bit Meaning 7 T2 bit 6 Bus Enable/Disk Step/Load 5 T bit 4 Disk Interrupt Enable 3 Not disk reset 2:0 Disk function 121 51 Load disk register file data 120 50 Load disk register file counter EIO buffers are enabled for all ports 100:137 octal (40:5F hex) and 300:337 octal (C0:DF hex) Mem : 140 60 Load Line counter 141 61 Load Display Address counter 142 62 Load cursor address counter 143 63 Load video status Bit Meaning 15:13 Map select 12 Write bad parity 11 Enable parity interrupt 10 Enable display? 9 Enable vertical sync 8 Enable cursor 144 64 Load cursor X posn 345 E5 Read CRT signals Bit Meaning 7 Landscape display 4 Line couner overflow 2 Loopthrough - low if all 3 boards in place 1 Vertical sync 0 Horizontal sync 346 E6 Read Hi address parity 347 E7 Read low address parity OIO: 000:003 00:03 Load SMD 4 004:007 04:07 Load Streamer 4 (and Canon Interface) 004 04 Load Canon Control Bit Meaning 4 Enable Canon Interrupt 3 Read Status 1 Reset Canon Interface 0 Not Blank 005 05 Load Canon Length Counter (Ports 4,5 may be swapped - I'll check) 014:017 0C:0F Load bit counter 024:027 14:17 Load Canon 4 024 14 Margin Counter control 025 15 Left Margin 026 16 Right Margin 030 18 Load SMD data 031 19 Load PERQ Control register for ethernet Bit Meaning 8 Go 6 Receive All 5 Not Reset net 4 Transmit 3 Enable Bit Counter 2 Enable usec clock 1 Enable usec Interrupt 0 Enable Net Interrupt 032 1A Load SMD 2 033 1B Load SMD 3 034 1C Load PROM 1 035 1D Load PROM 2 036 1E Ext Dev 1 Wr 037 1F Ext Dev 2 Wr 210:213 88:8B Read Canon 4 210 88 Read Canon Status 211 89 Read Canon Interrupt Bit Meaning 3 Status Full 2 Ready 1 Canon PRND 0 End of Band 214 8C Read SMD 215 8D Read Streamer 1 216 8E Read Streamer 2 217 8F Read net status Bit Meaning 7 Carrier sensed 6 CRC Error 5 usec clock overflow 4 Net Controller Status 3 Busy 2 Receive Transition 1 Collision 0 PIP 220:223 90:93 Ex Dev 41 Rd 224:227 94:97 Ex Dev 42 Rd 230:233 98:9B Ex Dev 43 Rd 234:237 9C:9F Ex Dev 44 Rd 240 A0 Read Link status Bit Meaning 3 Transmit Done Input 2 Flag Input 1 External Data cycle (Data Available) 0 Data to bus 041 21 Load Link Control Bit Meaning 3 Transmit done output 2 Flag output 1 Ext Data to bus 0 Data Cycle 242 A2 Read Link Data 043 23 Write Link Data 044 24 Write Loopback 245 A5 Read Loopback 200:237 80:8F Read I/O test PROM Multibus Adaptor : 000 00 Load Control Register Bit Meaning 7 Read cycle, Not write cycle 6 IO cycle, Not Memory cycle 5 Enable PERQ to do multibus cycles 4 Enable DMA 3 Initialise Multibus 2 Byte, Not word I/O 1 Enable Multibus Interrupt 0 Enable Interrupt on cycle complete 001 01 Write Data Register 002 02 Write High 8 address lines 003 03 Write Low 16 address lines and start bus cycle 006 06 Enable Interrupt lines 007 07 Write DMA Base (High 8 bits of DMA address) 212 8A Status Bit Meaning 15 Interrupt pending 8 Non existant memory 5:3 Multibus Interrupt number 2 Cycle Interrupt 0 Cycle complete 213 8B Read Data Register ----- What do the DDS numbers mean? The DDS (Digital Diagnostic System) is the 3-figure numeric display that is reset to 0 on a press of the reset/boot switch, and is incremented by the CPU on a clear stack microinstruction. It is incremented at various points during the bootstrap, and should the bootstrap fail, the number reached on the DDS can give a clue as to what the failure is. Here's a (partial) list of DDS codes. 0 - CPU not running, Clock failed, stack reset failed 1 - Branches fail 2 - Data path fail 3 - Dual address failed on registers 4 - Y register failed 5 - Constant/carry failed 6 - ALU failed 7 - Conditional branch failed 8 - Looping failed 9 - Writable control store failed 10 - Waiting for disk boot 11 - Memory data failed 12 - Memory address failed 13 - Disk not ready 14 - Could not boot from disk (or memory failed) 15-20 - bad interrupts from disk The system now executes software off the disk, so the DDS codes become OS-specific. ----- What are ICL-coded chips? Some UK perqs have chips with an ICL code, rather than the standard number. Here's an equivalent list for those I've come across - please e-mail me of any updates or corrections to this list. ICL Standard Equivalent --- ------------------- AZ 74S00 BZ 74S20 DZ 74S74 IZ 74S112 M20 74S138 M21 74S175 M25 74S153 M4Z 74S280 UZ 74S10 Y11 74S37 ----- CPU --- Can you give an overview of CPU operation? The CPU consists of a 20-bit ALU (24 bit on the T4), the inputs for which come from the A-mux and B-mux multiplexers. The B-mux is relatively simple, and switches the B-input from either the register selected by the Y field, or a constant. The A-mux selects between the register selected by the X field, memory data, an 8-byte queue of memory opcodes (selected by the BPC counter), I/O data, etc. The output of the ALU is fed back to the X-register, to the memory address register, the memory data register, and the I/O ports. There is a 16-level stack onto which the output of the ALU may be pushed, and which may be popped into the A-mux. The system is controlled by a RAM-loaded microcode (stored in the writable control store - the WCS) and sequenced by an AMD2910 sequencer circuit. The execution sequence may be modified by a condition code, or by various multi-way jumps (cf the forks in a DEC PDP11), such as the interrupt vector instruction, or the dispatch, which is used to decode opcodes. A raster-op machine is provided to speed up graphics operations, and incorporates a 16-bit barrel shifter that may also be used independently for arithmetic operations. There are several other facilities that are only of interest if you are attempting to repair or program the processor at a low level, and which I would be happy to discuss in a more specialised posting. ----- What is the format of the microcode word? The microcode word is divided into several fields, the meaning of which is as follows : bit 47 bit 0 XXXXXXXXYYYYYYYYAAABWHUUUUFFSSSSZZZZZZZZCCCCJJJJ X - X register number (Destination) Y - Y register number (Source) (Registers <77 Octal ORed with Base register). A - AMux Control 0 - Shifter output 1 - Nextop (Opfile[BPC]) 2 - IOD (IO Data Bus) 3 - MDI (Memory Data) 4 - MDX (Memory Data Extended - to bits 16-19) 5 - Ustate 6 - X Register 7 - Expression Stack B - BMux Control 0 - Y Register 1 - Constant (Y field, + Z*256 if long constant) W - Enable write to X Register H - Hold (Prevent IO from DMA). Also used for jump control U - ALU 0 - AMux 1 - BMux 2 - NOT(A) 3 - NOT(B) 4 - A AND B 5 - A AND NOT B 6 - A NAND B 7 - A OR B 10 - A OR NOT B 11 - A NOR B 12 - A XOR B 13 - A XNOR B 14 - A + B 15 - A + B + Carry 16 - A - B 17 - A - B - Carry F - Function SF Use Z Use 0 Special Function Constant/Short Jump 1 Memory/Extended SF Short Jump 2 Special Function Shift Control 3 Long Jump Long Jump S - SF (Special Function) Long Jump - Top 4 Address Bits Special Function 0 - Long Constant 1 - Shift On R 2 - Stack Reset 3 - TOS := R 4 - Push Estack 5 - Pop Estack 6 - CntrlRasterOp = Z 7 - SrcRasterOp = R 10 - DstRasterOp = R 11 - WidthRasterOp = R 12 - LoadOp (OP = MDI) 13 - BPC = R 14 - WCS[15..0] = R 15 - WCS[31..16] = R 16 - WCS[47..32] = R 17 - IOB Instruction (Input/Output) Memory Control/Extended Special Function 0 - R = Victim Latch 1 - Multiply/Divide Step 2 - Load Mult/Div Register 3 - Load Base Register 4 - R = Product/Quotient 5 - Push Long Constant (Estack) 6 - 2910 Address Inputs = Shift 7 - Leap Address Generation 10 - Fetch 4R 11 - Store 4R 12 - Fetch 4 13 - Store 4 14 - Fetch 2 15 - Store 2 16 - Fetch 17 - Store Z - Data field C - Condition 0 - True 1 - False 2 - IntrPend 3 - Spare 4 - BPC[3] - OpFile Empty 5 - C19 - No carry from bit 19 6 - Odd (ALU bit 0) 7 - ByteSign (ALU bit 7) 10 - Neq (Not Equal) 11 - Leq (Less / Equal) 12 - Lss (Less) 13 - Ovf (Overflow) 14 - Carry (Carry out of bit 15) 15 - Eql (Equal) 16 - Gtr (Greater) 17 - Geq (Greater / Equal) J - Jump 0 - Jump0 1 - Call 2 - NextInst (H=0), ReviveVictim (H=1) 3 - Goto 4 - Pushload 5 - CallS 6 - Vector (H=0), Dispatch (H=1) 7 - GotoS 10 - Repeatloop 11 - Repeat 12 - Return 13 - JumpPop (H=0) LeapPop (H=1) 14 - LoadS 15 - Loop 16 - Next 17 - ThreeWayBranch ----- What are the commands for the microcode sequencer? The 4K perq 1 CPU used an AMD 2910 sequencer, which has 12 address lines. Although the 16K CPU used in the PERQ 2 series needs a 14 address line sequencer, the AMD2910 is still used, but extended by a 2-bit extension built from TTL, PROMs and PALs. The AMD2910 data sheet is the best reference on what the sequencer commands are, which correspond to the J-field in the microcode word. ----- What is a short jump, long jump, leap? These refer to different sizes of jumps in the CPU microcode. A short jump is one in which only the bottom 8 bits of the address are changed. A long jump is one in which the bottom 12 bits of the address are changed. Both of these only use the 2910 sequencer. A leap may change all 14 bits of the microcode and uses the 2-bit sequencer extension as well. ----- What is the Raster-op machine? The Raster-op machine is a small finite state machine in the CPU which is programmed to perform operations on graphics bitmaps. Conceptually, it is similar to the Blitter in an Amiga. It contains a 16-bit barrel shifter, and combiner ROMs that perform the logical operation between the bitmaps. Unfortunately, there seems to be little documentation on this device. ----- How does the CPU do input-output operations? An output is easy - the ALU calculates the data to be sent to the port, the microcode Z-field specifies the I/O address (bit 7 = 0 implies an output port), and the CPU microcode decoder asserts the IO Enable signal. For an input, 2 microinstructions are needed. The first one specifies the I/O address with bit 7 set, whereupon the I/O enable signal is asserted, and the data from the port is stored in a latch on the CPU. The contents of this latch may then be processed by the ALU via the A-mux ----- Can I modify a 24 bit CPU into a 20 bit CPU? How about the other way? 24 bit (T4) CPU's may be downgraded into 20 bit CPUs by moving 2 links on the board. The first is just behind the ALU bank, and selects whether the final carry comes from bit 19 or 23. The other is the unmarked link a bit below the register bank, which selects the CPU identity bit. To upgrade a 20bit CPU into a 24 bit CPU is much more difficult. You have to provide an extra ALU, X and Y register for the extra 4 bits, rebuild the carry logic to accommodate the extra input, and then re-build the A-mux completely. I'll post any more information that I discover on doing this. ----- How do I debug a WCS failure If your DDS stops at 9, the quickest way that I've found to find the dead RAM is to buy 8 new 16K * 1 45ns RAMS, and then to push them over each bank of 8 rams in turn until the DDS gets to 10 or beyond. Then do a binary split on that bank to find the dead RAM, and replace it. This method has worked on every WCS failure I've had so far. ----- What are the edge connectors on the front of the CPU board? The Edge connectors on the front of the 16K CPU board provide access to the microcode address and data buses, and were intended for connecting to a logic analyser for debugging microcode. It appears that the pin numbering is slightly odd though - The convetional way to number the pins is : 1 3 5 7 ...... 47 49 2 4 6 8 ...... 48 50 The PERQ CPU pins seem to be numbered : 26 27 28... 48 49 50 1 2 3 ... 23 24 25 The end pins are numbered on the component side of the CPU board, and provide a reference. I'm not sure if the other pins have any connections though. I alos don't know if this pin-numbering scheme was deliberate, or an error in production. Anyway, here are the signals that I know about. JA is the top 50 pin connector, JC is the 26 pin connector at the bottom Un = microcode data bit n, UUAn = microcode address bit n JA1 - U0, JA3 - U1, JA5 - U2, JA7 - U3, JA9 - U4, JA11 - U5, JA13 - U6, JA15 - U7, JA17 - U8, JA19 - U9, JA21 - U10, JA23 - U11, JA25 - U12, JA27 - U13, JA29 - U14, JA31 - U15, JA33 - U16, JA35 - U17, JA37 - U18, JA39 - U19, JA41 - U20, JA43 - U21, JA45 - U22, JA47 - U23, JA49 - U24 JB2 - U25, JB4 - U26, JB6 - U27, JB8 - U28, JB10 - U29, JB12 - U30, JB14 - U31, JB16 - U32, JB18 - U33, JB20 - U34, JB22 - U35, JB24 - U36, JB26 - U37, JB28 - U38, JB30 - U39, JB32 - U40, JB34 - U41, JB36 - U42, JB38 - U43, JB40 - U44, JB42 - U45, JB44 - U46, JB46 - U47, JB47 - Disable microcode store (tie low to disable internal WCS and roms). JC1 - UUA0, JC3 - UUA1, JC5 - UUA2, JC7 - UUA3, JC9 - UUA4, JC11 - UUA5 JC13 - UUA6, JC15 - UUA7, JC17 - UUA8, JC19 - UUA9, JC21 - UUA10, JC23 - UUA11 JC25 - LD MIR' A (Strobe signal at the end of every microcode execution cycle). UUA12, UUA13 do not seem to be brought out anywhere. ----- Mem --- What memory boards existed? PERQ1's originally used a 256K board that was soon increased to 0.5Mbyte. The 1Mbyte portrait board was developed from this, and was the first board to be really supported in the PERQ 2. It drove portrait monitors only. This is the board that turns up in a lot of UK PERQ 2 T1's. This board was then modified (basically by adding a phase-locked loop for a faster dot-clock) to drive the landscape monitor. Some of these 1M landscape boards had the PLL hand-wired on prototyping board. These boards used 4164 64K DRAMs. I have been told that there was a 2Mbyte board that was portrait only, although I have never come across one, or seen any references to it. The standard 2Mbyte board had the PLL for landscape monitors, although they could be trivially modified to drive a portrait monitor. This design seems to be the most common PERQ 2 memory board, especially in PERQ 2 T2 machines. There are 2 main versions, which were built on the same PCB pattern - just a few links were swapped. I was told that one version was developed by ICL, and the other by 3RCC, but as they are _so_ similar, I find this hard to believe.The first design had a Mostek hybrid at each ram location which contained 2 4164 chips. The next revision had half as many 41256's, in every other column, but otherwise very few modifications. The PERQ T4 4Mbyte board had a full set of 41256's and a few links swapped to enable the extra address line. It was otherwise identical to the 2Mbyte board. ----- Can I increase the size of my memory board? Non-trivially. The 1Mbyte boards are almost impossible to expand, as there are no free locations for the extra chips (I now _know_ I'm going to get e-mail from people who've piggy-backed rams and hacked the address decoder...). The 2Meg board with 41256's can be increased to 4Meg, but this is only useful if you have a 24-bit CPU. ----- Can I use a landscape board with a portrait monitor, or vice-versa? The scan frequencies are the same between monitors, so if you don't mind a terribly distorted picture, you can just plug in and go. The 2 Meg(any version), and 4Meg landscape boards can be modified to drive a portrait monitor in the following way : Locate U270 - a 10104 chip. Pins 14 and 15 are bent up from the PCB, and pin 15 carries a twisted pair line, while pin 14 is not connected. Bend pin 14 so that it contacts pin 15, and solder them together (leave the twisted line connected as well). Now find the empty jumper position J15, near U218 (a 74S08 chip). Put a 2-pin jumper plug there. Fit a link on J15 for portrait monitors, remove it for landscape. Due to timing problems, it's a good idea to change U220 (a 74x157 multiplexer) as well - fit a 74S157 or 74F157 for landscape and a 74LS157 for portrait. Otherwise, you seem to get missing columns. ----- What are the useful links on the memory board for? J15 was mentioned in the portrait conversion. JP5,9,4 are fitted on the 2Meg (256K chips) board. These should be moved to JP3,JP10,JP7 on a 4Meg board. JP16 is removed on a 2Meg(256K chips) board. This enables the bankA chips). It is fitted on 4Meg boards, which enables address bit 2 to select bankA or bankB. If you have a failing 4M memory board, move the above links to reselect it as a 2Meg board, and remove JP16. This will select bank A only. If you ground the pin of JP16 that is connected to R25 (a 10k resistor), you will select bank B only. In this way, you can isolate a failing memory chip to 1 of the banks. ----- What is the trim-pot on the front of the memory board for? It sets the centre frequency of the Phase lock loop on the memory board. It's best not to twiddle unless you have video timing problems, when a small tweak may restore missing columns. ----- EIO --- What are the main sections of the EIO board? The main sections of the EIO are: 6 channel DMA controller for the microprocessor, Net Tx, Net Rx, Hard disk, and 2 external channels (used by the OIO) A Z80-A microprocessor controlling : 4 serial channels GPIB port Floppy disk controller Real time clock A finite state machine for the ethernet. A finite state machine for the hard disk ----- What is an NIO board? It's an EIO board without the chips for the ethernet circuit. ----- There are 4 serial channels. What are they used for? The 4 channels are controlled by 2 Z80 SIOs. The channels are used as follows: SIO 1 A - RS232 port A on the rear of the cabinet B - Tx - bitstream to the sound circuit Rx - Tablet input SIO 2 A - RS232 port B on the rear of the cabinet B - Tx - Not used Rx - Keyboard data ----- How is the sound produced? The synchronous bitstream from the SIO is fed, along with its clock into a motorola MC3417 PCM codec IC. The analogue output of this device is filtered by an Intel 2912 filter IC clocked at 2MHz, and then amplified by an LM380 before being fed along the display cable to the speaker. The codec is wired permanently as a PCM -> audio device. I've thought about using a second one (or more likely an MC34115) hooked up to the tablet port (which is the second half of the same serial channel) for sound input, but have never got round to it. ----- Where is the ethernet address stored? As far as I know, it's in the PROM NET13, which certainly differs between machines. ----- How do I set the links for different types of hard disk? I am informed that the PERQ 2 does not support the 14" shugart disk. The links to set are JP2 and JP3 near the front edge of the board (JP1 and JP2 on a 24-bit EIO board from a T4), and should both be fitted for 5.25" hard disks. They should both be removed for 8" micropolis disks. Note that the CPU microcode boot proms are different as well - MCxxxx proms for 8" and TCxxxx proms for 5.25" ----- OIO --- What is an OIO board? The OIO board is an optional input/output board that goes in slot 5 of the card cage. Several versions were produced by PERQ systems/3RCC, and there were also 3rd party boards to go in this slot. The original OIO board had support for a second ethernet port, a Canon laser printer engine, and a 16 bit parallel PERQ-link. ----- What versions of OIO existed? >From PERQ systems/3RCC, there were 3 versions of the OIO, depending on whether they supported the second ethernet, the Canon printer, or both. All versions included the PERQ-link circuits. The OIO-1 contained the ethernet circuitry, the OIO-3 contained the Canon controller, and the OIO-2 contained both. ----- What sort of Laser printer do I need? The Laserprinter connector (the pinout of which is given above) was designed to drive a Canon CX engine, as was used in the original LBP8A1, HP laserjet, etc. Unfortunately, Canon will not reveal the connections to the engine controller board in these printers, so that modifying such a printer for use with the PERQ is difficult. ----- What are the PERQLink connectors for, and what are the pinouts? The PERQLink is a 16-bit parallel I/O port that is connected to the 2 connectors on the front of the OIO board. It was originally designed to allow one PERQ to download boot microcode from another, during factory testing, and all PERQ 2 series microcode checks for an active perqlink early in the boot sequence. However, it can also be used as a 16 bit user port, and the pinouts are : Connector A - all inputs, Connector B - all outputs. Even # pins are ground 1 - Xmit done (rdy), 3 - Flag, 5 - RCSR->bus, 7 - Buf Cyc (strobe), 9 - Data 15, 11 - Data 14, etc, until 37 - Data 1, 39 Data 0. ----- What other boards went in the OIO slot? There was a wire-wrapped QIC02 tape streamer controller, produced in small quantities by PERQ systems. I think the extremely rare Multibus adaptor fitted in here also, and linked the PERQ backplane to an external Multibus card cage. I am collecting a list of 3rd party boards at the moment, but there was certainly a datacopy 300 CCD camera controller. ----- Can I add tape streamer support to an OIO board? Yes. There is enough space on the unused area to fit the necessary chips, and the I/O addresses do not clash, provided you don't use the tape and the Canon laserprinter at the same time (they share an output port). I'll look up the details and post them. The 26 pin connector on the OIO board is unused, and makes an ideal place to connect the streamer to. ----- What sort of tape streamers were supported? The PERQ systems tape streamer was an Archive Sidewinder in a case with PSU. Almost any QIC02 streamer should work. If anyone has a list of those that definitely do or don't, please e-mail it to me. ----- Is there any reason why the PERQlink connectors are similar to the DEC DR11? Yes. The OIO board has remained basically unchanged in design from the PERQ 1. Originally, PERQ microcode was developed on a PDP11 system, and the result downloaded to the PERQ via a DR11 (I guess a DR11-A) and an OIO board with PERQlink. I am trying to obtain information on this. ----- Monitors -------- Safety precautions. The Cathode Ray Tube in the monitor is dangerous. It contains a high vacuum, and could implode violently if cracked. Also, there are high voltages (typically 17kV), and the tube itself is the smoothing capacitor. Take extreme care if you decide to repair your monitor - there are few enough perq fanatics, and we don't want to loose any. Please ask if you are not sure - there are no stupid questions when it comes to repairing monitors. ----- What are the scan rates of a PERQ monitor? Veritcal : 60Hz Horizontal : 64kHz. These rates apply to both landscape and portrait monitors. All signals (syncs and video drive) are at TTL levels. ------ How do I open up a monitor? 1) Unplug it from the power supply (mains or 55V from the PERQ), and let it discharge for about 15 minutes 2) Remove the screws on the back cover, and slide the cover off 3) On a portrait monitor, remove the screws holding the metal plates round the back of the CRT, and _carefully_ pull the plates out 4) Remove the fixing screws for the stand, and take the stand off. 5) Most of the electronics is held by screws going through the base of the monitor. The KME portrait monitor (PERQ T1's) contains a PSU regulator heatsink at the back, the video circuitry on the tube base, and a PCB in the base which contains the scanning circuits and the flyback transformer. This monitor is conventional, except that it uses hybrid circuits in almost all stages. The Moniterm landscape monitor has the main PCB on the right (looking from the back), but the flyback circuit is not used to produce the EHT (it does produce supply voltages for video amplifier and tube heater). The EHT is produced by a separate EHT unit in the black box on the left. There is also a simple unregulated PSU. ----- What are the presets in the monitor? Landscape - from the rear of the PCB : P1 - Width P2 - Horizontal hold P11 - Horizontal dynamic focus P8 - Brightness L1 - Horizontal linearity P7 - DC focus P9 - Vertical DC centering P10 - Vertical dynamic focus P6 - Vertical linearity P5 - Vertical top-bottom linearity P3 - Vertical hold P4 - Height (On the EHT module - set EHT voltage). Portrait KME (on power heatsink - set power supply voltage - do not tweak!). VC1 - Horizontal phase L1 - Horizontal frequency L2 - Horizontal linearity VR1 - Vertical hold VR2 - height VR3 - Vertical linearity - bottom VR4 - vertical linearity VR5 - vertical shift VR7 - Horizontal hold VR8 - focus (tube base L1 - video peaking) ----- What do I do if the hybrids in my T1 monitor fail? Pray and panic :-). Seriously, I've not found a replacement, and can't trace KME who made the monitor. Your best bet is to redesign that stage of the monitor without the hybrid ----- My landscape monitor flickered a bit, and went blank. Help! Bob Davis (rdd) has covered the horizontal phase locked loop problems in his FAQ,which cause flickering, but not a blank screen. No, this indicates a failure of the (potted !) EHT module in the monitor, which happens all too often. The only cure seems to be replacement of the EHT module, and new ones are very difficult to find. Somebody will have to design an easy-to-build replacement for this part. In order to check, measure the voltages on the Blue and yellow wires coming from the EHT unit (take care). The yellow wire should carry +1000V, and the blue wire -110V. If either or both of these are low, the EHT unit has almost certainly failed. The tube final anode voltage should be about 17kV, and you can check this with a suitable meter. This also goes low when the EHT module fails. ----- What's the EHT unit in a landscape monitor? Physically, it's a black metal box bolted to the inside of the monitor cabinet, and connected to the tube final anode (EHT cable to the side of the tube), and to the monitor PCB. It supplies the 17kV final anode and +1000V/-110V to the electron gun controls. It is notorious for failing at the wrong moment. It contains a 1 transistor blocking oscillator which drives a small ferrite-cored transformer. The secondary windings on this transformer drive half-wave rectifiers for the +1000V/-110V supplies and a voltage multiplier for the 17kV supply. The 17kV output also feeds a potential divider that is fed to a comparator. There, it's compared to a reference voltage, and used to control the blocking oscillator, thus providing EHT regulation. Unfortunately, the device is encapsulated in silicon rubber, and debugging/repairs seem impossible. ----- Keyboard/Mouse -------------- What are the interfaces on the keyboard/mouse? Keyboard - 8 bit, 300 baud Asynchronous. Pinout is: 4 - Ground, 2 - Keyboard Data, 5 - +5V (note, pins on DIN plug numbered 1 4 2 5 3). The keyboard data stream is _almost_ inverted ascii for the printable characters. For those, the control key clears the top bit when pressed. The non-printing keys are a different though. A table of PERQ hardware keycodes is available, should you need it. Mouse - 8 bit synchronous. Clock comes from EIO board in PERQ. Pinout : 1 - +12V, 2 - Tablet Data, 5 - Ground, 3 - Tablet Clock. (Pins numbered as above). I will have to hook a logic analyser up to these devices, and see exactly what they send. ----- How do I open up the mouse and tablet, and what's inside? The Tablet is easy. The plastic cover just unclips, and then you remove the screw on the bottom, and lift out the PCB. When reassembling, note that 1 piece of cardboard goes above the PCB, the rest under it. The cables for the mouse and PERQ plug into connectors on the PCB. The PCB contains a 8748 microcontroller, and some control electronics. Traces on the PCB form the transmitting matrix that produces magnetic fields that are detected in the mouse. The mouse is glued together, but can be dismantled by using a sharp knife round the underside. It contains a sense coil, and 3 microswitches for the buttons, fitted onto a PCB. ----- What are the custom chips in the keyboard? There are 2 - Z1 (22-908-3B) and Z4 (22-950-3B). Both are for the Keytronics keyboard, and were not designed for PERQ systems/3RCC. Z1 (leftmost IC) is the keyboard Row Receiver. It contains 8 capacitive matrix sense amplifiers, driving SR latches. The outputs of the latches drive open-collector-with-passive-pull-up drivers, which are connected to Port 1 or the microcontroller. Port 2 bit 4 of the microcontroller resets all 8 latches - It's active low Pinout is : 1 - Row 0, 2 - Row 1, 3 - Row 2, 4 - Row 3, 5 - ResetOut, 6 - Row 4 7 - Row 5, 8 - Row 6, 9 - Row 7, 10 - Gnd, 11 - Out 7, 12 - Out 6, 13 - Out 5 14 - Out 4, 15 - Out 3, 16 - Out 2, 17 - Out 1, 18 - Out 0, 19 - Reset, 20 - Vcc Z4 is the column driver. It latches the lower 4 lines of port 1 of the microcontroller on the rising (?) edge of the clock pulse, also driven by Port 2 Bit 4. The 4 latched bits are fed to a 12 output decoder, and then used to drive the column lines of the keyboard. Pinout is 1 - Col 8, 2 - Col 9, 3 - Col 10, 4 - Col 11, 5 - Clock, 6 - Sel A 7 - Sel B, 8 - Sel C, 9 - Sel D, 10 Gnd, 11 - Sync, 12 - Col 0, 13 - Col 1, 14 - Col 2, 15 - Col 3, 16 - Col 4, 17 - Col 5, 18 - Col 6, 19 - Col 7, 20 - Vcc The microcontroller drives these chips in the following way. 1) Microcontroller puts out column address on port 1 (may appear corrupted at this point, due to the fact that some lines are held low by the row receiver chip 2) Microcontroller pulls Port 2 bit 4 low. This clears the row receiver latches, and thus uncorrupts the port 1 signals 3) Microcontroller sets port2 bit 4. This latches the column address in Z4, and then allows Z1 to pull port 1 lines low 4) Microcontroller sets all of port 1 high. This enables the signals to be used as inputs. 5) Microcontroller reads port 1, and thus sees if any of the rows were active. Repeat the above for all 12 columns. ----- Disks ----- How do I clean the floppy disk heads? Incidentally, Shugart, who made the 8" drive, do not recomend cleaning the heads. However, no damage will occur if you are careful. Firstly, you remove the Floppy drive from the machine (See the notes above). Then lay it circuit-board side down, and slacken the 2 screws holding the plastic cover over the head assembly. Remove the cover. Clean the heads using a cotton bud (Q-tip) dipped in disk cleaner (91% propan-2-ol, 9% distilled water). Reassemble the machine. Do not use a cleaning disk (aka sandpaper) in any machine I'm ever likely to see, as it will ruin the heads. ----- What is a DIB? A DIB is a disk interface board - the PCB mounted on top of the hard disk drive that converts the EIO signals into the micropolis interface or ST506. ----- Can I add a 2nd floppy drive? Not easily. The perq floppy disk controller does not use the drive select signals (apart from Drive 0). You may be able to enable the 2nd drive by inverting the Drive Select 0 signal and linking that to the select input on the other drive, but you'd have to re-write all the system software, including the z80 code file. ----- How about a second hard drive? This one's much easier. On a T2 or T4, you just need a second ST506 drive, the mounting bracket, and some cables. You fit the drive on the back panel, above the drive that's already there, remove the terminating resistor from the existing drive (remove the DIB to gain access), and make sure it's fitted to the new drive. You then set the drives to DS0 and DS1, use a straight 34 pin cable to link JC on the DIB to the 34 pin connector on each drive, and 2 separate 20 pin cables to link JD on the DIB to the data connector on the original drive and JE on the DIB to the data connector on the new drive. You'll find a power connector for the new drive on the power cable inside the machine. On a T1, I'm told it's possible to hang a second drive off the DIB, but I've never tried it, and I'm not sure where you mount it. Also, 8" hard disks are non-trivial to obtain now. ----- What are the pinouts of the 8" floppy drive? The important pinouts of the floppy drive are : (All odd-numbered pins are ground) 2 - Reduce write current 10 - 2 sided (output from drive if DS disk loaded) 14 - side select 16 - In use (not used on a PERQ) 18 - Head load 20 - Index 22 - Ready 24 - Sector (Hard sectored drives/disks only) 26 - Drive Select 0 28 - DS1 } 30 - DS2 } Not used on a PERQ 32 - DS3 } 34 - Step direction 36 - Step 38 - Write Data 40 - Write Gate 42 - Track 00 44 - Write Protect 46 - Rd Data 48 - Single Density Separated Data (not used on a PERQ) 50 - Single Density Separated Clock (ditto) ----- Can I use a 5.25" Floppy drive? I've never tried it, but I think that a 1.2Mbyte PC floppy drive will replace the 8" unit in the PERQ. You need to make a special cable to match up the right signals on the 50 pin PERQ cable (to the EIO board) and the 34 pin drive connector. ----- Does double-density operation work? On every PERQ 2 I've come across, double density operation works reliably. You need to use quality floppy disks though. ----- Power supplies -------------- Safety precautions All PERQ 2's use switch-mode power supplies. If you don't know what that means, stop, read a book on electronics, and then carry on. They rectify the line voltage and produce about 400V DC at a considerable current. This voltage is stored on some sizable capacitors, and the residual charge is nasty as well. Take great care if you decide to repair the PERQ 2 power supply. Also, Check the power supply works correctly on load before you put it back in the PERQ. If the 5V line is high, it could wipe out all the chips in the PERQ, and that's expensive. The PERQ T1 has 2 5V power supplies that are linked at the backplane. You have to adjust the voltages of each power supply until they deliver equal current. This is non-trivial,and you need a pair of 30A ammeters and some high-power load resistors for this. Don't fiddle unless you know what you're doing. ----- Are the PSU's the same between different models? The T2 and T4 power supplies are interchangeable. The T1 power supply is quite different. The T2/T4 unit has 1 5V 70A supply, and a second supply for the 12V and 24V rails. The T1 power supply also contains 2 units, each supplying 5V at 35A. The other supply rails are divided between the units. There is a 55V supply for the monitor on the T1 supply, but not on the others. Do NOT swap a T1 supply with any other type. ----- What are the ratings of the PERQ 2 PSUs I'll have to look these up! ----- What voltages can I get from the outputs on the back of the PERQ? The T1 monitor DIN plug has the following pin-out. 1 - +55V, 2 - 0V, 3 - Chassis. The T2 monitor plug provides 24V, but I'll have to look up the pinout. The tablet power connector was designed to supply a summagraphics BP1 tablet. It's a useful supply for home-made projects as well, and the pinout is : 1 - +5V, 2 - +12V, 3 - -12V, 4 - 0V. You can find some of the supply rails on the other connectors as well - see above for the pinouts. ----- What are the fuses on in the PERQ 2 psu? I'll have to look that up as well, but basically its the supplies to the peripherals - disks, keyboard, etc, and not the CPU cards. ----- How do I open up the PSU? Read the safety warning above!. Firstly, remove the power supply from the PERQ, as described above. Then, cut the cable ties holding the output cable to the back, and the ones holding the cables to the metal strip that runs from front to back inside the PSU. Remove the 2 screws on the back of the PSU, and the 4 screws holding the back panel to the supply units. Ease the back panel off. Then, remove the 2 screws holding the metal strip to the front panel, and remove this strip. Then, remove the 4 screws holding the front panel to the supply units. Now, you can unfold the PSU by placing it on one side, and lifting the upper supply unit and tuning it over. You can now reach the internals of the PSU. ----- What normally fails in the PSU? PERQ power supplies are very reliable, and the only failure I've seen is the failure of the chopper transistor (the largest power transistor in the supply). This blew the mains fuse, but nothing else. Like all switch-mode power supplies, the chopper transistor will fail from time to time, and it's worth checking the other components on the mains side when this happens. All the components (except the transformer) in the PSU are standard, and failures tend not to blow everything in sight. -----