Re: option ROM into a 3032

From: Francesco Messineo <>
Date: Fri, 29 Sep 2017 07:55:31 +0200
Message-ID: <>
On Fri, Sep 29, 2017 at 7:05 AM, William Levak <> wrote:
> On Thu, 28 Sep 2017, Francesco Messineo wrote:
>> On Thu, Sep 28, 2017 at 12:48 PM, Francesco Messineo
>> <> wrote:

> If you have an older PET (without CRTC) that has been upgraded to Basic 4.0,
> the jumpers may not have been set correctly.  There are jumpers that
> control addressing of the ROMs. If they are not set correctly you will have
> addressing problems. Check the schematics for correct jumper settings.

Yes, I was just going to check that. I've noticed the jumpers don't
match my 3032 (with older basic). The owner of this PET said it used
to work though, so I was assuming that the jumper were correct.
I will also change the timing resistor and tantalum capacitor on the
555 reset circuit, I've noticed the reset signal isn't very well
behaved (it resets randomly and sometimes doesn't release the reset
line). I think the tantalum capacitor is shorting randomly to ground
or the 1M resistor is intermittent.
Old hardware sometimes has lots of faults.

Frank IZ8DWF

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Received on 2017-09-29 06:02:35

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