Bringing some Nintendo’s back from the dead
At the start of my retro gaming obsession were a bunch of NES Nintendos. And like my usual self, I refused to pay heaps for them so I ended up buying 3 non functional NES’s with the intention of repairing them all and selling two of them off. Little did I know the state that they were in.
The first NES was rather straight forward, had a bad case ( chips in the corners ) a bad front power switch and a bad 72 pin connector so it was just a matter of ordering a new 72 pin connector and swapping over a spare lid that came with the other two NES’s.
The next two systems were purchased in non functional condition and with an unknown repair history, I soon found out that both of them had been badly fixed in the past with missing parts, patched wires joining broken traces and again bad 72 pin connectors, but this batch came with a whole bunch of spares as well. Both of them had issues that results in no picture on the screen and the notorious flashing red light and grey screen.
Getting down to it
The first NES with the bad connector was easy to fix, in terms of the power issue all that had happened was that a cable on the wiring harness was loose and needed to be pushed back in. While I was at it I cut the pin on the lock out chip to make it region free and I could play US titles and use my multi cart.
As for the other two, Well on of them ended up having bad ram chips, which were easily sourced from US sources. The other was far harder to diagnose the issue. I actually ended up buying a logic probe just for this project so I could figure out what was going on. Once diagnosing the issue and tracing all the pins and voltages it became obvious that the PPU was bad, more obviously determined by realising that the PPU was getting crazy hot. This was a lot harder to fix as this part is not available aftermarket, its a proprietary Nintendo chip. With some serious eBay trawling I ended up find some Russian clone chips that would do the trick. But between finding the chips and getting them an awesome fellow retro gamer gave me a donor board that I could take the chips from and I ended up getting it all going fine.
When the chips finally arrived I actually got the old board working and had almost socketed all the chips on it and it will become my new test motherboard for when other NES’s come across my table. Once I realised just how hard these chips were to obtain I ended up order more of them for spares and even found the matching Russian CPU clone chips.