Re: cbm8032 crashing at end of tape load...

From: didier derny <>
Date: Sat, 5 Nov 2016 15:51:43 +0100
Message-ID: <>

thanks for the information, I'll have to check these signal

I guess the signal leaving the 6545 is or I would have a bad display...

everything looks like if there was another source of irq above the one 
from the crtc...

the cursor looks mostly good but some time kind of high speed blinking

btw I discovered that on the address lines he the level 'high' was 
around 2.5v (with a 5.05v on vcc of the 6502)

it looks a bit low I'll have to check another machine..


On 05/11/2016 12:50, Christian Dirks wrote:
> I think /IRQ is generated by the 6520 on UB12 by VERT DRIVE on CB1,
> coming from the CRTC through the 7486 on UC2.
> Am 04.11.2016 um 21:46 schrieb didier derny:
>> now the cbm8032 is powered with 12v DC with 2 diodes added on the
>> circuit to drop the 12v to about 10.8v  (9.3v on unregulated connector)
>> when I check the 6v  on the tape connector it is at about 6.05v seems
>> correct
>> when I try to save a program everything looks ok
>> when I try to load a program seems ok to the ready but no cursor ?
>> any idea ?
>> I may have a clue... the cursor blinking seems irregular  I guess a
>> problem with the irq ?
>> any idea how the irq is generated on the 8032 ?  6522 ?
>> thanks
>> -- 
>> didier
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Received on 2016-11-05 15:00:02

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