I recently brought a PC350 back from the dead.

A good source of documentation for the F-11 is that for the 11/23 and 11/24 (e.g., http://bitsavers.org/pdf/dec/qbus/Digital_Microcomputer_Processor_Handbook_1979_80.pdf chapter 3 "LSI-11/23 Processor" or http://bitsavers.org/pdf/dec/pdp11/1124/EK-11024-TM-001_PDP11_24_System_Technical_Manual_Jun81.pdf)

The first thing I'd do is to attach a "console terminal" cable (a cable attached to the printer port with pin 9 pulled to ground -- pin 8).  DEC makes such a cable called BCC08 but I just made one myself.

Then use a terminal program at 4800 to send a break and see if you get the ODT prompt.

In my case I didn't get such a response.  It turned out that the leaky battery had destroyed the "EPCI" at E155 (the async serial chip for the printer/console terminal port).  I swapped the EPCI at E154 (the keyboard async serial chip) and I was able to at least talk to the ODT.  I then bought a replacement EPCI on eBay and I was on my way.

Good luck!

--Bjoren


On 5/3/2021 12:16 PM, Zane Healy via cctalk wrote:
On May 3, 2021, at 3:19 AM, Rob Jarratt via cctalk <[email protected]> 
wrote:
I have gone back to trying to fix my DEC Professional 350. I have a printset
for the machine now. I think the CPU is being constantly reset.

Is there any documentation anywhere on the F11 chipset? Bitsavers only seems
to have the later J11.
Is the Sunsite archive still online?  I seem to recall there being some 
documentation there.

Zane



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