Re: Looking for DEC M7264-CB Troubleshooting Documentation
If you are running a BA11-M box (3 1/2 inches tall), make sure the 2 fans are running up to speed. They slow as the fans go bad and can cause all kinds of H780 power supply and logic problems. When you shut the box the fans should spin for a few seconds. If they stop within a second, change it. Paul On Thu, May 9, 2019 at 6:58 PM Al Kossow via cctalk wrote: > > > On 5/9/19 9:57 AM, Mister PDP via cctalk wrote: > > I was wondering if any in depth > > troubleshooting material existed > > I'd start with the description in WD1600 chip set docs to see if > the basic microprocesor is running > > > http://bitsavers.org/pdf/westernDigital/MCP-1600/MCP-1600_Users_Manual_Oct77.pdf > > >
Re: Looking for DEC M7264-CB Troubleshooting Documentation
On 5/9/19 9:57 AM, Mister PDP via cctalk wrote: > I was wondering if any in depth > troubleshooting material existed I'd start with the description in WD1600 chip set docs to see if the basic microprocesor is running http://bitsavers.org/pdf/westernDigital/MCP-1600/MCP-1600_Users_Manual_Oct77.pdf
Re: Looking for DEC M7264-CB Troubleshooting Documentation
> From: Mister PDP > the 'Run' light does not come on when the switch is toggled Yeah, it wouldn't come on full unless it somehow fell into a loop of some kind - very unlikely. (Does that model LSI-11 have the on-board memory? I'm too lazy to look it up! :-) And what do you have the CPU jumpered to do on power-up? (ODT, 173000, etc.) But I would expect to see a brief flash. (Note: I don't have an LSI-11 plugged in to check this, I'm going by memory - the -11/23 certainly does the brief flash; if need be, I can pull out an -11/2 and plug it in, once I figure out if they are safe in Q22 backplanes.) I'd check the power voltages, and the clocks on the CPU board, and then look at BSYNC, etc to see if there's any hint that the ODT ucode is trying to read the console registers. No activity on BSYNC -> the ucode's not running. 'Small' QBUS systems - i.e. a single backplane - are OK to run with no termination on the far end of the bus (the CPU board includes pullups for that end), that shouldn't be an issue. Noel
Re: Looking for DEC M7264-CB Troubleshooting Documentation
I was referring to both the ODT prompt and the run light. I get nothing on the console and the “Run” light does not come on when the switch is toggled. On Thu, May 9, 2019 at 12:41 PM Noel Chiappa via cctalk < cctalk@classiccmp.org> wrote: > > From: Mister PDP > > > I was wondering if any in depth troubleshooting material existed > online > > I am not aware of any; I would be glad to be corrected. Unlike the early > gneration of UNIBUS CPU's, these generally weren't intended for internal > fault analysis and repair - module swapping and replacement was the > intended approach. > > The LSI-11 manual (EK-LSI11-TM-003) has a tiny bit of detail on how the > CPU board works (pp. 4-3 - 4-13), it's probably worth reading that before > diving into the CPU board internals. > > Things I'd check to start with - all the power voltages, and then the > clocks. > If those are all OK... BTW, for any serious fault analysis on these things, > you'll need a 'scope/logic analyzer. > > > When powered on, the CPU does not respond to the Run/Halt switch > either > > on the front panel or via the console. > > When you say 'does not respond', what's the symptom? Is the console ODT not > running (which could have any number of causes)? The whole system has to be > more or less running for ODT to work. I'd start elsewhere - e.g. does your > mounting box have the 'run' light? (It's driven by an output of the CPU > card.) Does that display any activity? > > Time to look at e.g. BSYNC, etc to see if the CPU is trying to read/write > the > console registers. > > Noel >
Re: Looking for DEC M7264-CB Troubleshooting Documentation
> From: Mister PDP > I was wondering if any in depth troubleshooting material existed online I am not aware of any; I would be glad to be corrected. Unlike the early gneration of UNIBUS CPU's, these generally weren't intended for internal fault analysis and repair - module swapping and replacement was the intended approach. The LSI-11 manual (EK-LSI11-TM-003) has a tiny bit of detail on how the CPU board works (pp. 4-3 - 4-13), it's probably worth reading that before diving into the CPU board internals. Things I'd check to start with - all the power voltages, and then the clocks. If those are all OK... BTW, for any serious fault analysis on these things, you'll need a 'scope/logic analyzer. > When powered on, the CPU does not respond to the Run/Halt switch either > on the front panel or via the console. When you say 'does not respond', what's the symptom? Is the console ODT not running (which could have any number of causes)? The whole system has to be more or less running for ODT to work. I'd start elsewhere - e.g. does your mounting box have the 'run' light? (It's driven by an output of the CPU card.) Does that display any activity? Time to look at e.g. BSYNC, etc to see if the CPU is trying to read/write the console registers. Noel
Re: Looking for DEC M7264-CB Troubleshooting Documentation
On 05/09/2019 11:57 AM, Mister PDP via cctalk wrote: Hello, As part of my H11A project, I am trying to debug my M7264-CB LSI-11 CPU module. When powered on, the CPU does not respond to the Run/Halt switch either on the front panel or via the console. I found engineering schematics for the M7264 online, but I was wondering if any in depth troubleshooting material existed online (Logic probe points, debugging steps, etc...). Well, first thing to check is that the bus is properly terminated, and that memory requests are being properly acknowledged. Jon
Looking for DEC M7264-CB Troubleshooting Documentation
Hello, As part of my H11A project, I am trying to debug my M7264-CB LSI-11 CPU module. When powered on, the CPU does not respond to the Run/Halt switch either on the front panel or via the console. I found engineering schematics for the M7264 online, but I was wondering if any in depth troubleshooting material existed online (Logic probe points, debugging steps, etc...). Thank You, Gavin
