Need to RAM clear a 550

[cruisepl]

Im having a problem with one of my 550 machines. When I turn it on I get one start up bong and 2 tilts

Operating System Data Corruption <Data Lost>
Configuration System Data Corruption <Main and Aux>

According to the service manual I need to Clear the RAM so I tried two of the three RAM clear chips I have but neither has worked properly. Before I try the third I figure I had better ask the question.

All three of my chips are handwritten with XU3 WMS Ram clear, one has 440C and 27C4001 and the other two have 2279 and 27C1001

I am thinking one of the 2279 chips is bad and thats why I have two but Im not sure.  Can somebody tell me which is the proper clear chip for a WMS550?

Thanks

[rickhunter]

When you say didn't work properly, what does the clear chip do?  Do you even get to the point where you can start the RAM clear procedure, or do you just never get to the screen.  Based on the chip type you listed, my guess is that the ram clear on the 27c1001 is a single denom chip, and that the 27c4001 is the "universal type" where you can select the denomination.  If you do get to the point where you go through the RAM clear procedure but still get the errors, my guess is that is an issue with either the EEPROM on the backplane or your battery might need replacement (although you should get a battery low tilt as well).

[cruisepl]

When you say didn't work properly, what does the clear chip do?  Do you even get to the point where you can start the RAM clear procedure, or do you just never get to the screen.  Based on the chip type you listed, my guess is that the ram clear on the 27c1001 is a single denom chip, and that the 27c4001 is the "universal type" where you can select the denomination.  If you do get to the point where you go through the RAM clear procedure but still get the errors, my guess is that is an issue with either the EEPROM on the backplane or your battery might need replacement (although you should get a battery low tilt as well).

Neither chip does anything as far as getting to the screen. Your right Rick about the 27C1001 being a single denom. I had to clear a WMS 440 quarter machine as well and that chip worked as expected in that machine. So that leads me to think the 27C4001 is for the 550 machine. Maybe not but I dont why I would have it if it did not clear one of my machines. All my dotmations are quarter so I only need the one chip for those.  I just put 27C4001 chip into the 550 and got the dreaded constant "8" in the window and "no signal" on the touchscreen. I pressed the reset button, no change. I put the game chip back in the machine and got the "8" again this time when I press reset I get the two data corruption tilts outlined earlier.  The "8" has me thinking that I have a bad board now.

So now the questions are:

Is the 27C4001 the right RAM clear chip for a nickel WMS550?  and
Did I fry a board thus giving me the constant "8" and no matter what clear chip I try it will not work?

Thanks


UPDATE.... I went over to the machine and turned it off, waited a while then turned it back on again. Screen said touch to confirm RAM clear, couple more messages and the machine came back up. Everything appears to play ok. Credits were at zero which was expected and the sound is really low.  Not sure if this is a problem with the speaker or maybe something else but Im not gonna turn off the machine right now to troubleshoot.  Just glad it was not a board. Knock on wood, I will probably get woke up tonight by a loud Williams bong.  lol