NES blank screen

[fwonkas]

I've got a front-loader NES that's giving me no end of trouble. I picked it up this weekend and, too my total lack of surprise, wouldn't play games. So I went about the normal process of disassembling it, cleaning the connectors, disabling the 10NES chip, etc.

 

No luck. Most of the time I get a blank white or purple screen. I will occasionally get Super Mario sounds (I've been testing with a SMB/Duck Hunt cartridge that I can verify works).

 

So I ramped it up and went after the connector on the main board with Brasso. It got a lot of nasty stuff off. I reattached the 72-pin connector and the load tray and it worked! Or at least I got the SMB/Duck Hunt intro screen. But it's only worked that once. Since then I get the same blank screen most of the time. I still occasionally get those sounds, and more rarely I get a very corrupted intro screen.

 

So I went to town on the 72-pin connector. Isopropyl alcohol, 600 sandpaper, the whole thing. Still nothing. So I ordered a new 72-pin connector. I got that yesterday. I plugged it in and got the exact same result.

 

Where do I go from here? Do I just keep on using Brasso until no black stuff at all comes off? Or could there be another culprit — maybe a bad IC? I can post pictures of the main board this evening if it will help.

[Osgeld]

so rubbing it the first time with polish made it work for a moment, but no luck since ... check for bad / cold / cracked solder joints, maybe you hit a sore point out of sheer luck to make it fire up

[fwonkas]

Good idea. I gave it a quick look-over last night and I didn't see anything obvious, but I'll go over it again with a bright light and a magnifying glass.

[fwonkas]

I'm still working on this. I've tried a couple things.

 

First, I tried tinning the connectors that the 72-pin connector attaches to. I was worried that I overdid it with the brasso. Still, no luck.

 

I didn't see any obviously bad joints, so I thought I'd try a reflow. I slathered the board with flux and went at it with a heat gun. This was the first time I'd tried a reflow on anything.

 

Again, no luck. It does the exact same thing as before — just a white screen. I'm about ready to throw in the towel here, unless someone has another idea. Should I try replacing some caps? Some ICs or memory chips?

[keoni29]

Old caps can be the problem. Have you done a cap kit on it yet? Did you get it to work?