Documentation for F11 Chipset?

[Rob Jarratt]

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-bounces at classiccmp.org> On Behalf Of Bjoren Davis via
> cctalk
> Sent: 03 May 2021 18:30
> To: cctalk at 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 at 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
> >
> >
> >