[Solved]Super Famicom - Video drops, Game stops randomly?

[SpoonyBard]

OK.

Still working on this old beast. More and more of the parts are SNES parts every day, but I am determined to get this specific unit working!

Replaced the cartridge slot (with a US one), replaced the sound board (also US), replaced the 1000v cap by the voltage regulator (new cap), cleaned it like crazy and now it boots regularly, reads carts, the sound plays fine, the video plays fine.

However, at random points during play, there will be some distortion in the graphics for a split second, and then the picture will drop out. The background music will still play, but based on the sound effects, the unit doesn't seem to respond to any controller inputs at this point in time. Tested this out with two separate, known working games and it does it with both. Ran it once for 45 minutes with no issues, another time for 20 until it finally stopped - yet sometimes it won't last more than a few seconds after turning it on. I'm wondering if it's time for a cap kit? Or if it's finally time to put this unit to rest. I bought this years ago, untested, and I have never had it working reliably.

Given the time, money and parts i've already invested in it. I'm not beyond replacing portions of it. I won't get the money or the parts back, and as long as it's cheaper than getting another SFC, i'm willing to give it a try. Any insights as to what may be causing this would be appreciated.

I've also got a pile of parts SNES systems with various problems and i'm willing to scavenge from those, but unfortunately this is my only SFC.

OLD
The sound effects aren't playing correctly. Almost as if they're replaced or just playing in a lower pitch. The cartridge connector came from a known working SNES, and the games i've tested all work 100% on a SNES (through a game geenie). - This was the fault of the sound board. Replaced with a known working unit and the sound functions properly.

[theclaw]

Super Famicom is like original Famicom. A different RF modulator intended for Japanese TVs.

Composite, s-video, and RGB, are the same as US.

[SpoonyBard]

I'm using a nintendo composite cable through the multi-out on the SFC, my CRT doesn't have composite ports though, so i'm sending it through a converter to dumb it down to coax.

I didn't know that about the RF out though, I picked this unit up without cables and wasn't sure if the US stuff would be the same or not. This is the first real import console i've owned.

[theclaw]

Try an NES RF switch and set the TV to channel 95/96.
Best chance of getting RF to work. Might be a different channel on your TV, or not supported.

[SpoonyBard]

Ha. Now to see if this old thing has a 95/96.

Otherwise I guess I can hook it up to the LCD.

[SpoonyBard]

Odd, my old CRT goes up to 125, but it has no channel 93-97. Regardless, no display on any channel on that. Hooked it up to my flat screen and got nothing on channel 95/96.

[SpoonyBard]

THREAD! RISE FROM YOUR GRAVE!

New issues in first post.

[Kidpanda]

I know this sounds crazy, but the SPC700 may be failing. I had one do similar actions, loud audio spikes and distorted audio, recapped the audio section and it still persisted. The only thing I could think of is the that the SPC is failing.

[SpoonyBard]

Getting closer! But i've got some new issues in the main post.

[SpoonyBard]

Just installed a new cap kit. One cap appeared to have leaked. Removed the old solder from the pads, cleaned up the surface with isopropyl alcohol and dropped new solder. Did a couple of test runs with Parodius and... Still having the same problems.

I did not crack open the SHVC board. The one I have in there was pulled it from a known working SNES. I'm wondering if there might be some kind of compatibility issue?

There was a slight improvement though. In playing, when the video started dropping instead of just flickering a few times and going to "no signal" on the screen, it kept flickering on and off. I could see the sprites get garbled (the background seemed to remain intact) and a lot of them dropped out. All motion stopped, the controller did not respond but the music seemed to play indefinitely. I let it sit and it took a couple minutes before the video dropped and went to "no signal" completely, whereas it would go to "no signal" and stay there immediately before the cap kit.

I still have the original Japanese SHVC board. But that one gave me sound errors. I'm wondering if it's worth the effort to recap it considering the difficulty of opening it and - as KP said, the possibility of other components having failed in it.

I've got decent tools, and i'm confident in my soldering - but i'm not entirely versed in electronics work, so i'm starting to get to a wall here. Not entirely sure what I can replace anymore.