Re: 1541 Assy# 250442

From: William Levak <wlevak_at_SDF.ORG>
Date: Wed, 30 Nov 2016 15:05:11 +0000 (UTC)
Message-ID: <Pine.NEB.4.64.1611301501050.20411@sdf.lonestar.org>
On Thu, 24 Nov 2016, silverdr@wfmh.org.pl wrote:

>
>> On 2016-11-24, at 06:10, William Levak <wlevak@SDF.ORG> wrote:
>>
>> Looking at the schmatic, I find a note that it is good for 250442 and 250446 with the following changes:
>>
>>     Component    250442      250446
>>        UD4        9602       74LS123
>>        R12        22K          15K
>>        C31        33pF      Eliminated
>>
>> It appears that the same PCB was used for two different assemblies.
>
> The problem is that 9602 and LS123 seem NOT to be pin compatible and I haven't noticed any patches on any of the 250442s I happen to have.
>
> Maybe the note means that the schematic is valid /also/ for 250442 and 250446 with the mentioned changes? Which file is the schematic in question? Could you share it?


The schematic is 251748.

The image you have posted has R12 as 15K and C31 is not present, so your 
board corresponds to the description of 250446.

I also notice that the image shows a paper label with an entirely 
different number on it.



wlevak@sdf.lonestar.org
SDF Public Access UNIX System - http://sdf.lonestar.org

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Received on 2016-11-30 16:00:03

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