Thanks everyone!
I exchanged the 74LS153s for some 54153s and at first no joy. ARGH! I
pulled the 74153s from my working board and everything was great. Subbed
in the 54s one by one and they worked just fine. I guess I didn't have
them seated properly the first time around.
At 01:31 PM 3/28/2004, Dave Langley wrote:
>At 07:41 am 27 03 2004, you wrote:
>>Thanks everyone for the input. It turned out to be a flakey 74153 on the
>>memory address bus.
>>
>>I socketed all 4 of them and things got much worse! I swapped them with
>>some from another board and problem solved! It turns out when I socketed
>>them I had not tracked which sockets they came from so the bad one was
>>moved and caused worse problems in the new location.
>>
>>I do have a question. I accidentally purchased some 74LS153s and tried
>>them and they do not work or are flakey. I know LS TTL chips are slower
>>than normal TTL but many times they will work. Is this part speed
>>sensitive in this application on the Williams board or is it more likely
>>these NOS chips are marginal/bad?
>
>I've used 74HCT153 in the past and they seem to work just as well as
>74153. I've never got a 74LS153 to work though ....
>
>
>Dave Langley
>www.robotron-2084.co.uk
>
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-- Franklin Bowen (Franklin@Bowen.net) http://fmbbowen.com:39353 --------------------------------------------------------------------------- ** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org ** Please direct other questions, comments, or problems to chris@westnet.comReceived on Thu Apr 1 21:01:45 2004
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