Re: Re: Star Wars Self-Test

Paul,

I just finished messing with a couple of Missile Command boards and they had
a couple of bad 74LS244s. My experience is that you typically drop the
pulsing data signal entirely. Most often they are stuck low.

If you use lots of flux and solder wick you can gingerly remove them intact.
I desolder and then use an awl to break the remaining solder bond. Then
carefully slip a jewelers screwdriver underneath and pry. Be gentle just in
case something is stuck. Go slowly and carefully.

Mark Hooks
----- Original Message -----
From: "Paul Maddern" <paul@arcadegeek.co.uk>
To: <vectorlist@vectorlist.org>
Sent: Friday, September 08, 2006 8:37 AM
Subject: RE: VECTOR: Re: VECTOR: Star Wars Self-Test

> Okay... With a new 74LS244 piggybacked in 1K a lifted leg looks
> completely
> different on the scope compared to the original chip... I don't get how
> comes the self test still reports that everything is okay? Am I
> overlooking
> something here? If I had a desoldering station I'd have replaced it by
> now,
> but the messiness of clipping it out and the self test are stalling me!!!
>
> Paul
>
> -- ArcadeGeek.co.uk --
>
>
> -----Original Message-----
> From: owner-vectorlist@vectorlist.org
> [mailto:owner-vectorlist@vectorlist.org] On Behalf Of peter jones
> Sent: 07 September 2006 23:15
> To: vectorlist@vectorlist.org
> Subject: VECTOR: Re: VECTOR: Star Wars Self-Test
>
>
> -----Original Message-----
> From: "Paul Maddern" <paul@arcadegeek.co.uk>
> To: <vectorlist@vectorlist.org>
> Date: Thu, 7 Sep 2006 20:01:10 +0100
> Subject: VECTOR: Star Wars Self-Test
>
>>
>> Hey All
>>
>> Just a quick question; my Star Wars PCB self-test reports all ROM and
>> RAM
>> okay, but how accurate is this?
>
> it can test the program roms by reading them and generating a checksum,
> it can test system ram by writing patterns to it and then reading back.
> the sound board has it's own selftest.
>
> one thing it cant test is the proms, and they fail a lot.
>
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Received on Fri Sep 8 18:12:33 2006