9 years ago I got a Pang for my personal collection. It was still with original battery and I carefully changed it with a new one because I didn’t like the wire wrap mod to desuicide it.
Unfortunately 1 year ago while testing the kabuki desuicider the game didn’t boot anymore, steady blue screen.
After testing succesfully the kabuki desuicider on another board it was clear my Pang developed a problem.
For more than a year I never managed to repair it until I got a Fluke 9010A which showed a problem on the z80 bus, the READ signal was not driveable.
I immeditely noticed that it had a very low resistance to gnd.
Near the Z80 there is a resistor network 4,7kohm. the read signal was connected to a pin of this network which had only a resistance of 427ohm.
I decided to desolder it and install a new one but the game didn’t boot.
I decided to let the game rest for some more time until one day I discovered that the game sometime booted , sometimes not but when it booted it crashed soon after.
Upon closer inspection I discovered that I soldered very loosy a pin of the network resistance!
After resoldering it better , the game booted without problems!