By the datasheet only the strobe line is slower, and that's only by 2ns. So I don't think that's the problem. But, for what it's worth, I had the same problem when I swapped the 74153s with ls's on a Turkey Shoot I was working on a while back.
steve
Franklin Bowen <Franklin@Bowen.net> 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?
Thanks!
PS I moved the bad chip around and took some pictures of the effects. See
here:
http://fmbbowen.com:39353/Video%20Games/NeedHelp/
At 01:24 PM 2/29/2004, =?koi8-r?Q?=22?=peter jones=?koi8-r?Q?=22=20?= wrote:
>-----Original Message-----
>From: Franklin Bowen
>To: rasterlist@vectorlist.org
>Date: Sun, 29 Feb 2004 12:54:02 -0700
>Subject: Re[2]: RASTER: Need help with Joust graphics output problem
>
> >
> > All the socketed chips (RAM, decoders, and CPU) in this board were moved
> > from a working board so I *HOPE* it's not a problem with the
> > RAMs! Actually I had to put the old CPU back because the known working
> CPU
> > gave me intermittent RAM errors! Weird.
> >
>try it again.
>it may indicate bad sockets.
>
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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.com --------------------------------------------------------------------------- ** Unsubscribe, subscribe, or view the archives at http://www.vectorlist.org ** Please direct other questions, comments, or problems to chris@westnet.comReceived on Sat Mar 27 06:28:08 2004
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