Re: Tempest boards playing blind (and worse)...help!

Speaking of Tempest problems, my tempest started drawing "magnified"
images (usually in "flashes", "bursts", or "short periods"). Note
this is NOT a monitor problem.

Using self test, it came up with a bad ram... which turned out someone
must have previously replaced as it was socketed. Swapping this RAM
out solved the problem.... for a while.... no it strikes periodically.

Could it be the socket ? Could something be taking out that RAM chip ?

The problem is so intermittent at this point, I haven't had it act up
long enough to use self test to see if the RAM shows bad at that point...
it doesn't occur often enough or long enough.... <sigh>

Any ideas/insights ?

The interboard wiring has been resoldered.

I have not replaced the 40 pin sockets on the math board (is this really
necessary ? Or is this only if you find corrosion of the socket pins ?).

-- Curt

>Content-Disposition: inline
>Content-Transfer-Encoding: 7bit
>MIME-Version: 1.0
>From: "Travis Shire" <boardjunkie@techie.com>
>To: vectorlist@synthcom.com
>Date: Tue, 07 Jan 2003 08:55:30 +0800
>Subject: Re: VECTOR: Tempest boards playing blind (and worse)...help!
>X-Originating-Ip: 24.236.175.66
>X-Originating-Server: ws1-11.us4.outblaze.com
>
>VoSsy VoS!!!
>
>With the one drawing crazy lines I'd start with the dac's, one or the other (or
both for that matter) is probably bad. The one with no video kicking the spot
killer should be a bad op amp in the output section. Check with a meter on each
axis' test loop to see if its stuck (they should normally fluctuate as the pix
is drawn).
>Follow the schem to see where you get a good input to an op amp stage and a
stuck output.
>
>Shouldn't be much of a problem to get them both back in action again.
>
>Laterz
>Travis
>
>
>
>
>Hey guys, I was unconverting my MH last night to sell as a Tempest...got one of
my dead Tempest boards going and popped it in.  Machine is working great. 
Figured while I was at it, I should try to get some others going.  I've got two
sets that play fine blind, but no video (spot killer on)...have another that
plays blind, but draws a few crazy random vectors, with the spot killer going on
and off rapidly.  Monitor sounds like hell during this, so I only ran it a few
seconds.
>
>Any suggestions on where to start?  This is the first time I've delved into
anything more than bad solder joints at the interconnect, as far as Tempest
boards go.
>
>Thanks,
>Richard
>--
>__________________________________________________________
>Sign-up for your own FREE Personalized E-mail at Mail.com
>http://www.mail.com/?sr=signup
>
>Meet Singles
>http://corp.mail.com/lavalife
>
>---------------------------------------------------------------------------
>** To UNSUBSCRIBE from vectorlist, send a message with "UNSUBSCRIBE" in the
>** message body to vectorlist-request@synthcom.com. Please direct other
>** questions, comments, or problems to vectorlist-owner@synthcom.com.

---------------------------------------------------------------------------
** To UNSUBSCRIBE from vectorlist, send a message with "UNSUBSCRIBE" in the
** message body to vectorlist-request@synthcom.com. Please direct other
** questions, comments, or problems to vectorlist-owner@synthcom.com.
Received on Mon Jan 6 21:45:12 2003