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PDP 11/73 M8190 Cache Error on Powerup.

shevett

shevett

Experienced Member
Joined
Jan 28, 2020
Messages
59
Location
Boston, MA
Hi everyone! I've inherited a PDP 11/73 that I'd really like to get up and running. I've gotten the serial console live, but on powerup I'm seeing

Error 62
M8190 CPU Cache Error

See troubleshooting documentation

(a few lines of registers and addresses)

I have the option of rerunning hte test or loop on test. Not a lot to go on.

Is this indicative of a bad mainboard?
 
Here's some more information. The actual error:

Code: 
Error 62
M8190 CPU Cache Error

See troubleshooting documentation


Error PC = 173346       PCR page = 05   Program listing address = 005346

R0 = 060000     R1 = 000001     R2 = 000361     R3 = 000001
R4 = 000400     R5 = 000000     R6 = 172300     Par3 = 000200

Expected data   = 000001
Bad data        = 000361
Address         = 00020000

BUT. I was able to get into the diagnostic prompt, and tried a map and boot:

Code: 
Commands are Help, Boot, List, Setup, Map and Test.
Type a command then press the RETURN key: MAP



Memory Map
Starting   Ending       Size in    CSR          CSR     Bus
Address    address      K Bytes    address      type    type

00000000 - 17757776     4088       17772100     Parity  Qbus

Press the RETURN key when ready to continue

I/O page Map
Starting   Ending
Address    address

17760440 - 17760456
17765000 - 17765776     CPU ROM or EEPROM
17772100                Memory CSR
17772150 - 17772152
17772200 - 17772276     Supervisor I and D PDR/PAR's
17772300 - 17772376     Kernel I and D PDR/PAR's
17772516                MMR3
17773000 - 17773776     CPU ROM
17774500 - 17774502
17776500 - 17776526
17777520 - 17777524     BCSR, PCR, BCR/BDR
17777546                Clock CSR
17777560 - 17777566     Console SLU
17777572 - 17777576     MMR0,1,2
17777600 - 17777676     User I and D PDR/PAR's
17777744 - 17777752     MSER, CCR, MREG, Hit/Miss
17777766                CPU Error

Press the RETURN key when ready to continue

I/O page Map
Starting   Ending
Address    address

17777772                PIRQ
17777776                PSW

Commands are Help, Boot, List, Setup, Map and Test.
Type a command then press the RETURN key: LIST

Device  Unit
name    numbers Source   Device type

 DU     0-255   CPU ROM  RD51, RD52, RX50, RC25, RA80, RA81, RA60
 DL     0-3     CPU ROM  RL01, RL02
 DX     0-1     CPU ROM  RX01
 DY     0-1     CPU ROM  RX02
 DD     0-1     CPU ROM  TU58
 DK     0-7     CPU ROM  RK05
 MU     0-255   CPU ROM  TK50, TU81
 MS     0-3     CPU ROM  TK25, TS05
 XH     0-1     CPU ROM  DECNET DEQNA
 NU     0-15    CPU ROM  DECNET DUV11
 NE     0-15    CPU ROM  DECNET DLV11-E
 NF     0-15    CPU ROM  DECNET DLV11-F

Commands are Help, Boot, List, Setup, Map and Test.
Type a command then press the RETURN key: BOOT DU0


Trying DU0

Message 12
No disk present or drive is not loaded
 
The problem could stem from several areas. I would first check for correct voltages + noise level on the power supply, fans operating and socketed chips seated firmly. Look for any electrolytic capacitors that may be distorted physically.

If its not any of these, then a bad cache memory or other chip would be the next focus.

Jerry
 
I am now seeing this exact same error on my 11/84. I'll check all those things suggested. It worked fine the last time I powered it on. But that was some time back.
 
If it was a bad cache chip or something in the cache control circuitry how would one determine what chip?
 
@czunit has supplied me with the XXDP diagnostics - the issue right now is getting the durn thing to boot off any medium. I'll be down at VCF East on Saturday where i'm going to pick up some more parts, I hope to at least try and get a floppy boot going this week based on the floppy images I have - if I can get XXDP or RT11 started, I can find out if the RD53 is dead or not, or if its the RQDX3, or something else.

After that, it's all just software. And that's the easy part, right? (right?)
 
I believe I have found the diagnostic. It downloaded as OKDAG0.BIC. I have never used XXDP so have to learn how to configure something that I can boot it from and run the test. My 11 has no floppy drive. I normally create a bootable image using Simh and then DD that to a SCSI drive which I can boot from. I wish I could attend VCF East, as it's been quite fun in the years I have attended.
 
TU-58 emulation over a serial port comes in pretty handy for running XXDP based diagnostics.
Click to expand...
No argument! In fact, I have a pair of DLV11J's,. but sadly the cables were cut on them. I bought one of Glitch's cables so I can go full TU58 once I'm powered up again. Thanks for the pointers, there'll be a good evening of hacking soon :)
 
Now I just have to figure out how to get the OKDAG0.BIC file into a TU58 image for use. Perusing the documents from the links you included. I think I used TU58em long ago for making a real bootable RL02. That had to be 15 years ago or more. Thank you for the links.
 
@nadaveiron I am so doing this. I need to determine if i'm going to use two USB <-> RS232 connections on my Linux laptop (console and TU58) or haul out a 'dumb terminal' to be my console. This'll be fun :)
 
I still have the M7856 card from the last time I ran TU58. I even wrote on it with a Sharpie TU58. I can't remember how I hooked it up to my PC back then. It has a Berg connector on board. Can XXDP be set up on a SCSI drive and then booted? Say from Simh and then moved over? Once again I have never used it ever.
 
tradde said:
Can XXDP be set up on a SCSI drive and then booted? Say from Simh and then moved over? Once again I have never used it ever.
Click to expand...

One handy thing I have done is to build an MSCP bootable XXDP disk image using SIMH, then burn that disk image to a CD-ROM, then I can boot that XXDP CD-ROM from a SCSI CD-ROM drive attached to an MSCP controller. I think you need to have a SCSI CD-ROM drive that can be jumpered for 512-byte sectors instead of 2048-byte sectors for that to work. Most Plextor SCSI CD-ROM drives should have such a jumper.
 
I have such a said CD-ROM I believe. It's SCSI and was attached or came with my DEC Multia. There's a hard disk there too. I do not know what it is. I have never powered up either. The Multia's battery died so it makes it harder to boot as the system info is gone. I know it can be put back temporarily, but someday I will find a battery for it. Then again it's not well liked by most Alpha people. And supposedly it runs hot too. So the CD-ROM device will be a DU#: unit? So the burning CD drive will have to have that also for 512 byte sectors?
 
PDP11GUI requires a Windows machine. I have none. I'd rather not set up a VM to run it. And I am not sure it would work there anyway.
 
I have all the diags extracted from the RL02 pack, just in case. Now to figure out how to do the next step.
 
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