TECH: Robotron 2084 RAM errors
Shannon Dunmyer
Howdy gang. I snagged a nice original Robotron 2084 on Sunday, but being a
newbie, I throw myself upon the mercy of the experts.
When I power it up, the seven-segment LED display on the ROM board assembly
shows 1-1-4 pause 1-1-4 and the monitor reads initial tests indicate RAM
error (different every time I power it up. either 21, or 34, etc) then it
shows a stereogram looking test pattern, and blurts about half a second of
music, and comes back with
some other RAM error.
Anybody ever dealt with this before?
Thanks folks, always a pleasure.
*If everyone played Robotron 2084, there would be no war*
http://lonestar.texas.net/~dunmyers
Scott and Ruth
Shannon Dunmyer wrote:
Been ther, dun it. big time.
The self-diagnostic confuses power supply (+5 V) problems with RAM
errors. You can spend the rest of your life replacing RAM's to no
avail.
If you can, test the capacitors on the power supplu board. As a
guess, replace the big one. In my experience it dires out and fails
first.
If you want to rid yourself of re-occurance of this problem, buy a new
power supply and wire it into the 5volt circuit.
How much did you pay for the game?
scott
--
Message Sent From: Scott Dalrymple and/or Ruth Hitchcock
Our e-mail address: da...@lynx.org
Robotron Competition: http://www.lynx.org/dalco/video
Scott and Ruth
Rex Nelson
Fixed many with the same problem.
You may have a bad ram or two but most likely it is the power supply board.
Most likely it is bad solder joints on the power supply board.
Resolder all of the pin connectors and clean any burnt ones with a little
sand paper.
After resoldering and replacing the ram chips. If you still have a problem
then
you should recap the power supply board.
You can get your 411 ram chips at B.G.Micro. they cost about $0.70 each.
Here's there number: 1-800-276-2206
Good luck and let me know if you still have problems and I will tell you
what to check
next.
--
Rex Nelson
email iam...@airmail.net
***************************************************************
Looking for the following arcade games working or not.
Quantum, Major Havoc, Zektor, Robotron, Black Widow,
Blaster, Joust 2, Galaga, & any Atari color XY monitor parts.
Shannon Dunmyer wrote in message <64tko2$oo$1...@news3.texas.net>...
Chris Bright
jwe...@ccwf.cc.utexas.edu wrote:
>
> In any case, RAM failures ARE common on these games, so I
> would first check the voltages, and if they are good, start replacing
> the RAM chips that the machine tells you to replace...
>
First thing I would do is reseat all the connectors that come to the
boards from the power supply. When I got my Robotron it had power
problems which were fixed by just cleaning the connectors and the pins
they slip on to. Actually, I put a little bend in the connector that
supplies +5 to the main CPU board so it would make a little better
contact. Two years ago and haven't had a problem since. Yes,I still
have the origional power supply in the game.
--
Chris Bright - CAT Development Team - S024
| / ___ ) __ ) __ __/ ___/ /
/ | / / / / / / / /
/ | / / / _ __/ / ___/ /
/ | / ( / / \ / / /
__/ __/ ____/ __/ _\ __/ _____/ _____/
WTB: Major Havoc Board
jwe...@ccwf.cc.utexas.edu
Scott and Ruth (da...@lynx.org) wrote:
: Been ther, dun it. big time.
: The self-diagnostic confuses power supply (+5 V) problems with RAM
: errors. You can spend the rest of your life replacing RAM's to no
: avail.
There are 3 LEDs on the power supply, one for +5, one for +12,
and one for -5. If any are not lit, you've probably got a P.S. problem
(I've had the LEDs go bad before.) If all are lit, it doesn't
necessarily mean that your power is good, though. Measure the voltages
at the RAM chips with a voltmeter.
: If you can, test the capacitors on the power supplu board. As a
: guess, replace the big one. In my experience it dires out and fails
: first.
It's very hard to test capacitors. I wouldn't touch that BFC
(Big Capacitor) on the power supply. The 2N3055 power transistors,
the LM723 voltage regulators, and the bridge rectifiers are all more
likely to fail and cause bad power, than the capacitors.
: If you want to rid yourself of re-occurance of this problem, buy a new
: power supply and wire it into the 5volt circuit.
Please don't do that. Unless you're an operator, mutilating your
game to put a switcher in there really isn't worth it. My average repair
time on these Williams supplies is under 15 minutes, the cost of
repair is under $10, and most all the parts are available at Radio Shack.
An economical switching supply has to be mail ordered (from BG Micro
or whereever....Altex sells PC supplies for $30...ouch)
In any case, RAM failures ARE common on these games, so I would
first check the voltages, and if they are good, start replacing the RAM
chips that the machine tells you to replace...
Joe
--
------------------------------------------------------------------
Joseph J. Welser jwe...@ccwf.cc.utexas.edu
Design Engineer -- Crystal Semiconductor Corporation
Ph.D. Student in E.E. -- University of Texas at Austin
Work: jwe...@crystal.cirrus.com http://www.crystal.com
P.O. Box 17847; Austin, TX 78760
------------------------------------------------------------------
Shannon Dunmyer
>How much did you pay for the game?
>
$200 US