Sadly my machine is not at the point where I can attach a console of any kind. The CPU is being reset every 13us by a bus error. I am having trouble working out why though. I have got as far as working out that is the CT2 TIME OUT signal, but just why that is active isn't entirely clear to me. It would help to have a working machine to compare it to!
Regards Rob > -----Original Message----- > From: cctalk <cctalk-boun...@classiccmp.org> On Behalf Of Bjoren Davis via > cctalk > Sent: 03 May 2021 18:30 > To: cctalk@classiccmp.org > Subject: Re: Documentation for F11 Chipset? > > 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_Hand > book_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) Thanks for the tips, I will take a look. > > 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. > Sadly my machine is not at the point where I can attach a console of any kind. The CPU is being reset every 13us by a bus error. I am having trouble working out why though. I have got as far as working out that is the CT2 TIME OUT signal, but just why that is active isn't entirely clear to me. It would help to have a working machine to compare it to! Regards Rob > 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 <cctalk@classiccmp.org> > 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 > > > > > >