What Would Cause a Ram Error After Every Power Up?

[DB26]

Hello everyone,

I have a 504B MPU, Varta removed and a brand new coin cell battery testing at 3.2 volts.

My machine has a ram error every time you pull the board out and put it back in, and almost every time you power the machine on after having it switched off.

I noticed this today when I was messing with the MML sounds. I pulled the MPU, added an MML board and got the ram error. I pulled the MML board off and reinstalled the MPU and got another ram error. This is all without touching any of the chips. I powered the machine off and then back on again and got another ram error.

The machine clears the credits every time, and turns the reel stop solenoid back on, too.

This might be related, but the other day I noticed the candle flicker for a split second when a game was in play. It did that a few times through that session and gave me a reel tilt for a few of those flickers.

[DB26]

EDIT: Nevermind the problem still persists. It went away for only a few minutes.



Okay here is something interesting. I have multiple sets of chips for this machine so I put another set of (copies) chips in and it does not give me the ram errors anymore. Saves the credits and solenoid settings too. The flicker and general reel tilt happens very sporadically so I am waiting to see if that pops up again. Sometimes it general reel tilts on all three, just last two or just the last reel. It is different every time.

The message is Closure MB General Reel Tilt

[RB]

A poor battery connection would cause it. Be sure the solder pads for the battery are not damaged on both sides of the battery top and bottom. If that is all good, try another pair of RAM chips before trying another MPU.

[DB26]

A poor battery connection would cause it. Be sure the solder pads for the battery are not damaged on both sides of the battery top and bottom. If that is all good, try another pair of RAM chips before trying another MPU.

Well both problems came back.

Thanks RB. I tried all of the above and the problem still persists. Reflowed the battery connections, changed the ram chips and swapped MPUs. The problem goes away with a new MPU. This board has zero Varta damage so I wonder what the problem is.

Still clears the ram on power down and gives random closure MB general reel tilts. Hmmmm

[RB]

MB: main closure, cash box door. That's what causing the tilts. Likely it does have Varta damage whether you see it or not.

[DB26]

Yes, I agree, too bad. Another 504b bitten the dust. But it happens so intermittent that I can use this board for testing chips, I suppose.

[DB26]

I have to hand it to fellow member lookes. He contacted me and told me the symptoms of my problem sounded like it could be a problem with U4 or U52 on the MPU. I replaced U4 first since it was the easiest and my problems have gone away. I feel pretty proud of this since it was my the first real test of my new hot air soldering station and my newly acquired skills.

[RB]