PCB Repair Logs R-Type
R-Type
 |
|
| Manufacturer | Nintendo |
|---|---|
| Year | 1987 |
| PCB Image | Reserved |
| Pin Out | Reserved |
Repairer: Arcade King
Forum Thread: R-Type PCB Repair
Problem: Boots up with RAM NG 1 error.
Fix: In the manual error code NG 1 is work ram which is the 2 64k rams on the program board labeled M72-ROM-C. I replaced the rams with no change. Noticed a 74ls245 @ A1 doing nothing. Replacing it fix the pcb.
Problem: Games gets to RAM OK ROM OK then freezes.
Fix: Corroded track(see attachment) to pin 2 on the PAL IC19. The source comes from a 74ls373 pin 12 IC13 and goes to pin 7 IC 11 (another PAL) and pin 5 on another PAL on the rom board @ A3 as well as the fore mentioned PAL.
NOTE: WHAT A ****ING PRICK OF A FAULT! Must of worked on and off on this PCB for a month. I could see the INT on the CPU wasn't being enabled like it should but I did not know or could find the cause of it.
The INT to the V30 CPU comes from pin 19 of a Interrupt control Unit (D71059C IC74). Using my working R-Type I also found that the pin beside it pin 18 (Bufr/w) was suppose to be High, this one was dead. I naturally assumed the chip was stuffed and pulled another one off a spare M72 cpu board...no go. I then traced everything back that inputs to the chip with no luck. Theres times when repairing PCB where you can't find anything wrong yet you just start pulling shit off at random
Problem: Sound works for about a minute then fades out.
Fix: Bad M51516L Sound amp. The metal plate of the amp has been broken off so chip is overheating and thermal protection circuit kicking in.
