OP

Quoted from dmesserly:

I ordered some 2803 and 339 chips to replace the U20 and U19.
Basic advice request...I don't have a special tool to pull chips. Is there a preferred method using screw driver to pry or pliers to grip and pull?

OP

Quoted from dmesserly:

OK part way there then failure...
I replaced the socketed U20 and U19 on the CPU. Put the CPU back and reconnected to game. The game booted up with no errors.
I had forgotten to reconnect the three POA connectors under the playfield. When I did and rebooted the game I got the original Ground Short Row 5 error message and no row 5 switches work.
Disconnect the POA connectors and the game still throws the error.
Disconnect connector 207 and 209 and still throws error.
I took out the mini playfield and can't see any worn wires or obvious shorts. Same with other switches in row.
I'm at a loss for how to hunt this down but I assume that there is a problem somewhere in the row 5 switches.

OP

Quoted from dmesserly:

Yes. I assume I probably did that but I need to find out what to do to locate and fix problem in playfield.
I guess my question is how do I locate a short in a row of switches if I can't find any visible cause?
THanks.

OP

Quoted from dmesserly:

Don't know what was wrong but I reinstalled the CPU and double checked the connectors and I am not back to a fully working game with all switches working except I have not reinstalled the POA which has two switches in Row 5. Last time I reconnected the POA after everything was working to that point, I got the Ground Short Row 5 error.
I have examined the switches and wiring on the POA and can find no visible worn wires or things touching where they shouldn't. Can someone give me some pointers on how to find a short on the POA or what to test for before I reinstall again?

OP

Quoted from dmesserly:

Don't know what was wrong but I reinstalled the CPU and double checked the connectors and I am not back to a fully working game with all switches working except I have not reinstalled the POA which has two switches in Row 5. Last time I reconnected the POA after everything was working to that point, I got the Ground Short Row 5 error.
I have examined the switches and wiring on the POA and can find no visible worn wires or things touching where they shouldn't. Can someone give me some pointers on how to find a short on the POA or what to test for before I reinstall again?

OP

Quoted from dmesserly:

I found some switch tests on pinrepair.com. Tested all switches for continuity and they are working.
Do I need to remove the diodes to test them?

OP

Quoted from dmesserly:

Thanks for all the tips and advice. I had looked over the switches and wiring on the POA Several times but I tried again again found a wire in a bundle that was worn and near metal. I wrapped it and put the POA back and reconnected everything.
IJ is now back and fully functioning. Played a bunch of games with no issues.