I game main battery low problem

[dansgames]

I have an I game with a 3902 rev A board. I had to replace the battery took it to interstate and had them solder in a new one.
Went to power it up still got Main battery low. Check the battery voltage (good) ran a clear procedure but still comes up main battery
low. Any help greatly appreciated.

Thanks  Dansgames 

[Tilt]

Check R36 near the battery.  It should read 100K, but will probably read significantly higher if it's bad.   I had two boards with that problem and replacing it fixed them both.

[dansgames]

Thanks Tilt will check it tonight.

Dansgames 

[azgamingslots]

do the battery backed up static ram chips on the cpu board ever discharge? -what codes do they give?

[Tilt]

Yes.  The machine will display a "Main Battery Low" error message on the screen.

[azgamingslots]

so it could be one of the batteries inside one of the static ram chips?

[Buzz]

so it could be one of the batteries inside one of the static ram chips?

I think they are referring to the battery on the MPU.  I've never heard of a battery inside a chip. But I've been wrong before.   

[azgamingslots]

static ram chips (like the Dallas chip) contain two small non rechargeable lithium batteries. they last for years, however when the batteries die, the whole chip must be replaced and ram restored or cleared.

some of the slots that used self powered static ram chips were games of nevada, P&M, some bally and shufflemaster card shufflers.

u-22 on the earlier game king cpu boards looks like a static ram chip., however not sure if it's self powered.

[stayouttadabunker]

I had to replace those Dallas chips to get my video working correctly on a game about 4 years ago.
See the 2 big black chips on the bottom of the picture?
Those have small batteries built into them to retain the memory -
I'd be surprised if they have chips like that in the I-Game but you never know?

You'll see them in the pictures I posted on Reply #6...>>>

http://newlifegames.net/nlg/index.php?topic=16731.msg6993#msg6993

[azgamingslots]

pretty sure u-22 on the game king is a static ram chip.  -i remember an Australian game king rolled through her a few years back -seems like it had a couple dallas chips  on the board.

[dansgames]

Thanks for all the replies, it turned out to be the R39 was open. Special Thanks got out to
Tilt for isolating what chip it was.

Dansgames   

[CaptainHappy]

Check R36 near the battery.  It should read 100K, but will probably read significantly higher if it's bad.   I had two boards with that problem and replacing it fixed them both.

Thanks for all the replies, it turned out to be the R39 was open. Special Thanks got out to
Tilt for isolating what chip it was.

Dansgames  

Just to prevent any future confusion for people who check out this thread later on... Please confirm if it is R36 or R39 or maybe both could cause the problem?

CaptainHappy

[dansgames]

Originally We thought it was the R36 causing the problem, upon further investigation it turned out to be the
R39  ( 1m ohm ) that was open, It's on the same path as a R36..  Again Tilt gets full credit 
for isolating the bad chip

Dansgames   

[CaptainHappy]

Originally We thought it was the R36 causing the problem, upon further investigation it turned out to be the
R39  ( 1m ohm ) that was open, It's on the same path as a R36..  Again Tilt gets full credit 
for isolating the bad chip

Dansgames   

Thanks for the confirmation that both can be suspect!   To you and Tilt.

CH