Harmony cart attacked by aliens

[Ben E Boi]

My Harmony cartridge was playing fine, then all of a sudden a garbled screen appeared. I can still play games by moving the joystick and guessing but the games are garbled too. I reformated the card and updated the bios without change. Photos attached:

[+batari]

I have seen strange things like that happen before and in the past it was due to one of the chips in the console going bad. Maybe it only goes bad when it's warm or some other issue like that. I'd let it cool down and try again and see if things work again, and also if the problem comes back when it warms up again.

 

I'd also try some regular carts first and play the same game on either to see if it behaves the same way. And, if you have another console to try, give that a shot.

[Mr SQL]

10 hours ago, batari said:

I have seen strange things like that happen before and in the past it was due to one of the chips in the console going bad.

It could be coincidence but those spots seem to correspond to the interference pattern; maybe the interference burned out some of the gates in the chip over time from micro current characteristic with a very low amperage high voltage/high frequency bleed, like we saw from Smart Meters activating Mr Coffee unscheduled.

 

[+batari]

3 hours ago, Mr SQL said:

It could be coincidence but those spots seem to correspond to the interference pattern; maybe the interference burned out some of the gates in the chip over time from micro current characteristic with a very low amperage high voltage/high frequency bleed, like we saw from Smart Meters activating Mr Coffee unscheduled.

Only problem with that theory is the voltages here are extremely low, unlike smart meters. If high voltage, high frequency interference burned out NMOS chips then the 25kV from every CRT would fry them, and we definitely don't see that.

[Mr SQL]

3 hours ago, batari said:

Only problem with that theory is the voltages here are extremely low, unlike smart meters. If high voltage, high frequency interference burned out NMOS chips then the 25kV from every CRT would fry them, and we definitely don't see that.

That is an excellent point, the 25,000 volts from that Tesla coil has virtually no amperage but it can indeed weekly bridge logic gates allowing heavier currents to flow to weakly activate devices like Mr Coffee. This is the reason the high potentials are inside a Faraday cage, to prevent the high voltages from jumping, even insulation and air gaps break down as a resistor over 10K volts.

 

With the interference lines present in the video signal for some specific games there is some kind of unidentified minor field interference generating them. It hasn't hurt either of my Atari's and I've left them on for days even with games that have the lines. Of course it's possible it might have a cumulative effect over time or interaction with other devices - I've seen CF bulbs generate a lot of THD (harmonic distortion) where the high potentials (those are about 10k) can hit much higher harmonics (100,000 volts +) wreaking havoc with dimmers and Mr Coffee old electronics because the CF bulbs  leak badly having no Faraday cage.

 

[+DrVenkman]

TIA is going bad in the OP’s 2600, most likely.

[Ben E Boi]

I tried the Atari again today and it is doing the same thing with all cartridges (except some of them are blank screen). I am thinking this may not be an electrical problem, but yes the TIA going bad. Do I need to take out the TIA and read something off of the chip to replace the same exact one?

[+DrVenkman]

7 hours ago, Ben E Boi said:

Do I need to take out the TIA and read something off of the chip to replace the same exact one?

The TIA is an Atari-specific custom chip. New ones are only available from Best Electronics and lately they've gotten stupid-expensive as stock gets lower. You can buy used chips online but your luck will vary with that. You can also salvage one from a beat up parts machine if you find one cheap enough to be worth it.