Received 2 boards from member Phetisboy for repair. A 2 board Donkey Kong and a 2 board Donkey Kong Junior.
First board was Donkey Kong Junior:
Problem: Was told board reset after level 1 was played. I cleaned the Z80A and reseated the Eproms Played game for several days and never had the issue of resetting occur. Checked power on the edge connector and all the caps and power to the IC chips everything was in normal specs. Even plugged it back in today after it had been sitting around for a week while I was in Tenn at my mothers funeral. No Charge to the customer for board work.
Second board was regular Donkey Kong:
Problem: Board would not boot up at all even though it had power.
Soultion: Found Broken Transistor leg at Q8 on the CPU Board. Replaced with new transistor still not booting. Checked rest of transistors and diodes and did ESR checks on caps and still nothing. Checking Video board found missing IC chip at location 1E it had been socketed and the socket on one side was broken. Replaced broken socket with a new socket and looking at the schematics found the missing chip to be 10136 replaced chip and turned game back on and now we have video. Coined the game up and the game still had problems this time the game would freeze up after you lost all your lives and sometimes if I shook the pcb board the game would unfreeze. The solution was to start checking the Eprom Chips for corrupt data. The culprits turned out to be 2 bad Eproms on the CPU board. 5C was corrupt and I was able to reprogram that chip by erasing it and reprogramming the chip. Next, 5E was bad I had to replace with a brand new chip which I programmed cause the old Eprom wouldn't allow me to reprogram it. After all that I retested and now the game was playing great through all levels. I even shook the board to see if anything would happen and nothing kept playing normal and I played for hours. I love Donkey Kong its so fun. P.S installed new pots on the video board because the old ones were ready to break off the picture would jump if you barely touched the pot.
First board was Donkey Kong Junior:
Problem: Was told board reset after level 1 was played. I cleaned the Z80A and reseated the Eproms Played game for several days and never had the issue of resetting occur. Checked power on the edge connector and all the caps and power to the IC chips everything was in normal specs. Even plugged it back in today after it had been sitting around for a week while I was in Tenn at my mothers funeral. No Charge to the customer for board work.
Second board was regular Donkey Kong:
Problem: Board would not boot up at all even though it had power.
Soultion: Found Broken Transistor leg at Q8 on the CPU Board. Replaced with new transistor still not booting. Checked rest of transistors and diodes and did ESR checks on caps and still nothing. Checking Video board found missing IC chip at location 1E it had been socketed and the socket on one side was broken. Replaced broken socket with a new socket and looking at the schematics found the missing chip to be 10136 replaced chip and turned game back on and now we have video. Coined the game up and the game still had problems this time the game would freeze up after you lost all your lives and sometimes if I shook the pcb board the game would unfreeze. The solution was to start checking the Eprom Chips for corrupt data. The culprits turned out to be 2 bad Eproms on the CPU board. 5C was corrupt and I was able to reprogram that chip by erasing it and reprogramming the chip. Next, 5E was bad I had to replace with a brand new chip which I programmed cause the old Eprom wouldn't allow me to reprogram it. After all that I retested and now the game was playing great through all levels. I even shook the board to see if anything would happen and nothing kept playing normal and I played for hours. I love Donkey Kong its so fun. P.S installed new pots on the video board because the old ones were ready to break off the picture would jump if you barely touched the pot.
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