RE: Gravitar Weird Start up / hi score save

Jess,
I checked the voltages and the -28V measures -27.95V at the test point and
at the leg of the chip. It seems steady with a DMM. Do you think the caps
could still be problematic? Btw 5V is running at 5.05V.
 
I also noticed that on the weird graphic issue. cycling the power to the cab
fixes it., but jumping the reset test points doesn't. it will come back up
with the disjointed vectors and klingon text.
 
Thanks,
Bob

  _____

From: owner-vectorlist@vectorlist.org
[mailto:owner-vectorlist@vectorlist.org] On Behalf Of Jess Askey
Sent: Tuesday, September 20, 2005 7:35 PM
To: vectorlist@vectorlist.org
Subject: Re: VECTOR: Gravitar Weird Start up / hi score save

The EAROM uses a capacitor doubler circuit to produce something like -28V
for the EAROM. It runs off the -15V supply I belive. Im doing this from
memory so it may be +28V running off the +15V supply.

anyway, when the doubler caps dry out, the supply drops back down to +/-15V
and the EAROM won't work that way. There a diode as a part of the doubler
but I have never seen that go bad, just the electrolytics. Try replacing
both of those and I bet you will be good to go.

I guess first measure your voltage to see if it is low tho. :-)

good luck

Bob Langelius wrote:

I just got Gravitar running in my Space Duel cab. At cold start it has weird
letters and vectors. A power cycle fixes it.
 
Also the Hi scores don't save after a power-down. I changed Earom - same
situation. How does the earom work? Do they fail from age or use?
 
Self test shows no failures.
 
Thanks,
Bob

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Received on Thu Sep 22 09:11:17 2005