Re: PET 3032 issue

Interestingly, the failed RAM chips were UI2 and UJ2, both of them on D7 line.
The only explanation for this coincidence is that one of them failed
and "hit" the other sitting on the same bus line.
Another interesting thing is that to identify UI2 I had to fill that
bank with some locations having D7 high and some having D7 low, and
then it started to make D7 output all 1 in all locations.
That's why petester didn't identify this one (it identified problems
with UJ2 though, after swapping the CAS lines).
I think that the 3032 isn't yet fully functional. Basic runs fine for
as much as I could test, but
if I try to activate an option ROM installed in UD3 (marked SuperTool
3032, see my thread of some months ago) with SYS37000, it goes into
the monitor.
People trying this option in VICE told me it works.
So still searching for problems.
And, almost forgot, looking for hot chips, I spotted a way too hot
MC3446, so now I'm looking for one :/

Frank IZ8DWF

On Sat, Feb 4, 2017 at 8:26 PM, Francesco Messineo
<francesco.messineo@gmail.com> wrote:
> On Sat, Feb 4, 2017 at 8:21 PM, Gerrit Heitsch
> <gerrit@laosinh.s.bawue.de> wrote:
>> On 02/04/2017 07:00 PM, Francesco Messineo wrote:
>>>
>>> Ok some progress.
>>> It turns out that the petester.bin image only tests one 16K bank, not
>>> both (on my board, only the innermost bank).
>>> Swapping the CAS lines (R41, R42) did show some errors and I
>>> substituted one 4116, I thought I was lucky since the petester didn't
>>> show any error anymore, so I put back the original kernel ROM and it
>>> did indeed boot fine.
>>> I swapped back in their original places R41's and R42's ends and...
>>> black screen again.
>>> I socketed and substituted another 3x4116 but that didn't revive the
>>> PET. So I swapped again the CAS lines and I'm going to write some test
>>> programs to understand what are the bits that don't work as expected.
>>
>>
>> Doesn't the 3032 have TIM? You should be able to find the broken RAMs from
>> within the Monitor.
>
> sure it has it. But the only way I've found to have it "boot" was
> swapping the CAS lines.
> I'm going to test the ram with these lines swapped right now.
>
> Frank

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