Fixing problems - a how-to

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Obsolescence

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Feb 27, 2016, 6:26:09 AM2/27/16
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Attached is a document that describes how to diagnose and fix PiDP problems if, after soldering, it does not behave.

Feel very very much invited to amend and extend this document and please post it back in this thread! Suggestion is to highlight amendmends in a different colour, or as side comments. That'll make the flow of improvements easier to trace.

Regards,

Oscar.
Checking a new PiDP.docx
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John Kennedy

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Aug 16, 2019, 12:02:50 AM8/16/19
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Hi - 

Just a quick note to point out that these instructions seem out of date. I'm trying to work through them to fix my PiDP8, and given a fresh SD install:

* At launch, there's a login prompt, so CTRL+E won't do anything as simh isn't available.

* When you do get to simh by logging in and starting pidp8i, then you can do a CTRL+E to get the sim> prompt, but you'll find that "ex ma" doesn't do anything (invalid argument).

(My issue turned out to be a bad solder joint on a switch.)

Warren Young

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Aug 16, 2019, 3:56:13 AM8/16/19
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On Thursday, August 15, 2019 at 10:02:50 PM UTC-6, John Kennedy wrote:

"ex ma" doesn't do anything (invalid argument).

Indeed: the MA register isn't exposed at the SCP level. It would have to be defined in the cpu_reg table within pdp8_cpu.c. I can see how you'd add it — and probably MB as well! — but that should really be done upstream, not at the PiDP-8/I level.

However, doing so is not actually necessary. I believe you can already get the effect desired at that point in the document with "ex sr". The SR register was not set properly in the last release from Oscar, but I fixed that problem in the 2017.02.04 release.

That document should also mention pidp8i-test, probably in preference to SCP commands.

Warren Young

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Aug 16, 2019, 3:57:29 AM8/16/19
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Rather than update this DOC file, this material should just go into the project's wiki. Hint. :)

John Kennedy

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Aug 16, 2019, 11:40:07 AM8/16/19
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I'm happy to update the Wiki. The information should be copied and added to a new doc here? https://tangentsoft.com/pidp8i/wcontent

My issue seems to have been a faulty Raspberry Pi as well as a bad soldering job. Waiting for replacement Pi to confirm..

Warren Young

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Aug 16, 2019, 12:21:20 PM8/16/19
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On Friday, August 16, 2019 at 9:40:07 AM UTC-6, John Kennedy wrote:
I'm happy to update the Wiki.

The hint was for Oscar...it's his document, so his copyright to release. He's given me license to copy some things into the repo, but that doesn't give me the right to copy everything he's ever published.
 
The information should be copied and added to a new doc here? https://tangentsoft.com/pidp8i/wcontent

I think we probably want an embedded document, actually, since the troubleshooting steps can clearly vary when the software changes. Wiki docs are for evergreen content that applies to all versions.

So, it'd go in "doc/hw-trouble.md" or similar, with the embedded images in "doc/graphics".

John Kennedy

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Aug 17, 2019, 1:07:05 AM8/17/19
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I guess my issues with the instructions are dependent on how I got the image onto the SD card. Broadly speaking, if I download the ready-to-go img file it will behave as above (i.e. a bit wrong), otherwise if I start with a working distro/noobs and install the PiDP8 files it will behave the way described in Oscar's docs. Hence my confusion.

As an aside, I think I have narrowed my issues down to a combination of:

1. A bad solder joint on two switches
2. A faulty Raspberry Pi
3. A corrupt SD card (either cheap card, or not shutting down correctly, or both).

At the moment, everything is copacetic.


On Saturday, February 27, 2016 at 3:26:09 AM UTC-8, Obsolescence wrote:

Steve Tockey

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Aug 26, 2019, 4:57:26 PM8/26/19
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Oscar,
A minor tweak is necessary on:


Option 2A, step 2 has the line

cd pidp8

the line needs to say

cd pidp8i


Thanks,

-- steve


Mike Katz

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Aug 26, 2019, 4:59:54 PM8/26/19
to Steve Tockey, PiDP-8
Oscar,

I found this as well but I forgot to post that here.

Steve, thanks for posting it.

             Mike
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Oscar Vermeulen

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Aug 26, 2019, 5:30:17 PM8/26/19
to Steve Tockey, PiDP-8
Steve,

Thanks, fixed. But in fact that whole procedure needs to be rewritten, Warren showed a better one. But this gets the job done, if you've come this far.

Kind regards

Oscar.


Warren Young

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Aug 27, 2019, 12:26:09 AM8/27/19
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On Monday, August 26, 2019 at 3:30:17 PM UTC-6, Obsolescence wrote:

that whole procedure needs to be rewritten, Warren showed a better one

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