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I installed the modification kit into my VA62 before I had checked out the basic operation completely. There were problems, so I put the original EPROM back in. The problems were still there so it wasn't the EPROM and I rechecked the added switch modification and it was fine.
Luckily the kit had included a CDROM with a lot of info including schematics and a maintenance document. Also Phil Nelson on this forum had scanned the schematics and some documents.
I started by checking the internal main power supplies. I found some voltage were out of spec and some have more hum than spec. It became evident that someone had worked on the unit before, some resistor were not the value in the schematics and parts list. I corrected that. I changed a voltage regulator IC and replace some filter caps. The meter circuits had their own power supplies that I check next. I replaced a regulator there also. Then I made a mistake re-connecting a cable. Many cables use a pin header on a circuit board and the mating plastic block connector on the cable. If you are not careful you can plug the cable to the board with the pins offset from the right place. That had happened and the wrong voltage was put on a large IC that ran the display on one side. That chip was messed up afterwards. The IC was obsolete long ago. I found one on ebay in Germany. I waited weeks for it to arrive. I contacted the seller who said he would send another. More waiting, it didn't arrive either. I contacted the seller and got my money back. Then I found the IC at a company in the US and get it in three days.
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