Replacing a 5500 MPU

[jdkmunch]

Hi,

I just got a replacement 5500 MPU and I am having some trouble getting it to start up.  I replaced all chips and checked all of the jumpers to make sure they are the same on both boards.  When I power it up I get error 82 9.  I tried to to a ram clear but when I set the jumper and press pseudo and test nothing happens.

1.  What is 82 9  - 
2.  On my old board there is a chip in socket u26 - on the replacement there is no chip there.  What is that chip for?


Thanks

[paul]

Is there any nos on chips 3-4 12-15 , if your old board you colld ram clear, then switch 3 and 4 and 12 and 15 and try to clear new board, check for bent pin if you took chips form old board

[jdkmunch]

What is nos?

[a69mopar]

he meant numbers

W

[a69mopar]

82 Door Open With PowerOFF The machine door was opened while the main power was off (Requires JW11 IN).


take the jumper off JW11 if it is in, or check if the pins are touching.

I think it's odd that the u26 is missing, They aren't socketed on my boards, they are soldered in.  Was this a known working board?

Here is what the u26 is for (pic)

Good luck,
Wayne

[paul]

Wayne I have a few boards with U 26 missing still work dont know what this is for the only boards i have with it in, they are soldered in

[a69mopar]

Maybe they are an early or late version, still shows it on the schematic though.

Thanks,
Wayne

[StatFreak]

My 5500's have the older '95 ROMs that allow me to do jumper-only RAM clears without the set chips. They all have U26 soldered in place.

<ADD> My boards' component layouts are all the same as those in jdkmunch's picture.

[jdkmunch]

If you look closely you can see that this board had the U26 installed and someone removed it.   I contacted the vendor and he is going to replace the entire board for me.

It would be interesting if with the proper clear chips the board would work without this chip.

I did check the JW11 and there is no jumper on it.   The battery checks out ok too.