Re: option ROM into a 3032

From: Ethan Dicks <>
Date: Thu, 28 Sep 2017 17:28:25 -0400
Message-ID: <>
On Thu, Sep 28, 2017 at 1:14 PM, Francesco Messineo
<> wrote:
>> it's every 8 chars. Now I first have to replace the UD9 socket...

Those sockets are not high quality, so that's also a good call.  I
replaced all of them in the 3032 I got as a teenager.

> turns out the "every 8 chars" flickering was a bad UF8 (MOS 2114 variant).
> UF7 (the twin MOS 2114) had also a few bad cells (3 that I could
> observe using pettester.bin image).

Not surprising.  Most vintage stuff with 2114s, that's the first thing
I look at when they fail oddly.

> Now for the real "funny" part: pettester.bin shows no error both on
> VRAM and on the system RAM, but using the original kernel EPROM on UD9
> gives a garbage screen.

That is odd.

> I've tried to swap the 16K banks but no change.

Then it seems likely your 4116s are good.

> Looks like there're still problems.

Does the petester do checksums on the ROM sockets?  The code is kinda
small, so I'm guessing not.

> Does anyone feel like coding a much more useful test image for 2001N? :D
> Debugging a PET without a logic analyzer can require a "funny" amount of time.
> I think a good test program that can be put in the kernel socket would
> speed up the process.

Does anyone know where the petester images came from?  I saw that they
were posted about 2 years ago and I glanced at a hexdump, but I
haven't gone as far as disassembling the code to see what it does.  If
there's source out there, that would save a bit of time.


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Received on 2017-09-28 22:00:04

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