On Wed, 30 Nov 2016, William Levak wrote: > 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. I have opened up 3 1541s. the numbers on the circuit boards do not match any numbers on my list of versions. However, the numbers on my list of versions do match the part numbers on Commodore's relacement parts lists. It appears that Commodore used two different munbering systems. In determining which version you have, you should use the descriptions of the board and not the number on the circuit board. wlevak@sdf.lonestar.org SDF Public Access UNIX System - http://sdf.lonestar.org Message was sent through the cbm-hackers mailing listReceived on 2016-12-02 09:00:02
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