LS devices have less current drive available. One 74XX gate can drive
10 X 74XX gates, or 100 X 74LSXX gates, however one 74LSXX gate can
only drive 1 (ONE!) X 74XX gate or 10 X 74LSXX gates.
LS devices run cooler as a result and thus the system as a whole uses
less power...and the response time is improved, and the current
surges on the 5VDC buss are reduced...etc.etc..etc.
John :-#)#
>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 <Franklin@Bowen.net>
>>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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Received on Sat Mar 27 11:02:37 2004
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