Re: ROMs replacement

From: Gerrit Heitsch <gerrit_at_laosinh.s.bawue.de>
Date: Mon, 08 Oct 2012 21:29:32 +0200
Message-ID: <5073299C.6070900@laosinh.s.bawue.de>
On 10/08/2012 09:07 PM, silverdr@wfmh.org.pl wrote:
>
> On 2012-10-08, at 20:25, Gerrit Heitsch wrote:
>
>>> http://dl.dropbox.com/u/58002657/cbm/c64/rom_adapter_0.png
>>
>> Looks OK to me... Please check in your circuit if the direct connection of pin 13 of the LS00 and pin 3 of the LS11 to +5V is there
>
> Yes, both are in place.
>
>> Could you upload a picture of the circuit as used?
>
> PCB:
> =====
> http://dl.dropbox.com/u/58002657/cbm/c64/Scan-121008-0001.jpg
> http://dl.dropbox.com/u/58002657/cbm/c64/Scan-121008-0002.jpg


Well... the schematics show the unused gate of the 74LS11 as having all 
inputs grounded. But I see no traces on the PCB connected to pins 9, 10 
and 11. Did you add that later with wire to pin 7 or has that gate all 
inputs floating open? If the latter, please fix this and try again.

  Gerrit







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Received on 2012-10-08 20:00:51

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