Tech TOTAN - DMD Dark

MisterP

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Aug 17, 2012, 9:48:17 PM8/17/12

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Got through playing a game on TOTAN and the DMD completely blacked out.
Not a dot to be seen. Put the DMD in another pin and it worked. I am as
dumb as a box of nails trying to troubleshoot this - I searched archives
and pinwiki, but no luck.

I checked connections and ribbons and fuses and looked for something
obvious, but nothing jumped out. Or dangled.

Does this sound familiar to anyone? I am too green on these DMD games
to get too adventurous and would appreciate any hints I can get.

Thanks, and have a great weekend.

--
MisterP
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Lloyd Olson

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Aug 17, 2012, 10:05:00 PM8/17/12

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If the DMD was fine in a different game, then next up would be to measure
the voltages on the DMD at the big connector, see if any are low or missing.
You may need to rebuild the high power section that drives the DMD.

Your manual will have the connector and voltage into - careful some of them
are high.

LTG :)

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MisterP

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Aug 17, 2012, 10:14:13 PM8/17/12

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Thanks Lloyd,
I read that online, but the part about keeping one hand in my back
pocket made me hesitate to check voltages. Don't want to die before Woz
gets here! I will proceed cautiously.

Lloyd Olson

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Aug 18, 2012, 12:13:31 AM8/18/12

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You won't die. Just get bit a little. Be careful anyway. LTG :)

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MisterP

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Aug 18, 2012, 8:15:59 AM8/18/12

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Thanks Lloyd

MisterP

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Aug 18, 2012, 7:45:39 PM8/18/12

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I did not die. I tested the voltages. I cOuld not find the voltages in
the operations manual but pinwiki showed:
anode -112v
12 v dc offset -100v
5 v dc offset 5v
12 v dc 12v
Cathode 62v

I tested 115.8 for anode, 104.7 for 12v dc offset, 5.08 for 5v dc, 11.67
for 12v dc, and 3.3 for cathode. Looks like cathode may be the winner.
I tried to test a couple ways, and results were similar. The cathode
power degraded further as I went along testing.

I am green on all of this - what is entailed in rebuilding the high
power section? I appreciate any guidance that can be shared!

Lloyd Olson

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Aug 18, 2012, 8:02:47 PM8/18/12

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http://www.greatplainselectronics.com/Category-45.asp Scroll down, Ed has a
kit for you.

Not too bad. If you don't have board work experience I would suggest
practicing on an old board and when you can remove and replace things
without damaging board or traces, you are ready to fix your game.

LTG :)

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Lloyd Olson

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Aug 18, 2012, 8:07:52 PM8/18/12

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If you need help with the board repair, contact Rob Anthony
http://lockwhenlit.com/ he posts on RGP as Borygard.

When you remove the board, pictures or notes on what connector goes where
and which way it faces can help. Ribbon cables have a red stripe on one
side - should be at pin 1 each end.

LTG :)

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MisterP

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Aug 19, 2012, 12:13:00 PM8/19/12

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Thanks Lloyd. I will keep Rob's contact info. We have AFM and CV too,
and I figure I will need another AV board eventually, so I ordered one
from BAA. No problem having a spare. Will probably send this one off for
repair - I still can't get the hang of soldering.