7800 splash screen then black (NTSC)

[ruddy_canuck]

I have experience fixing 2600s, Vic 20s etc and I bought my first 7800 for repair. 

 

7800 games - The initial 'splash screen' shows up then the screen goes black. The plot thickens, my 7800 copy of Dig Dug goes to the game screen briefly before the black screen appears.

2600 carts don't work at all, they seem to act like a dirty slot/cartridge.

 

I've cleaned the slot in my usual way but I'm wondering if these symptoms really do seem like a slot issue or if this is a known fatal-ish problem?

 

Power is good, I've made a custom power adapter for it.

[juansolo]

With those symptoms my first port of call would be the cart slot. Rather than just reflow it I'd pull the whole thing, give it a thorough inspection for bent pins, try and retention any that look slack, give it a thorough clean and put it all back and see if there's any difference. If it's happening on multiple carts it's most likely that. If it's only happening on one cart, possibly the cart. The fact you get the splash screen means the system has booted and is at least trying to read the cart.

 

While you have it apart, do the usual, like make sure you have a solid 5v coming out of the regulator.

Edited August 9 by juansolo

[+-^CrossBow^-]

@ruddy_canuck As you can't get either 2600 nor 7800 games to load. I think I'd start with the CPU first. You are getting the 7800 splash screen so that tells me that the BIOS is detecting the cartridge properly and trying to do the encryption check but then fails at that point to load the cartridge further. Although since you are able to briefly see the dig dug screen for a brief instant, would seem that the cartridge is being read. So again, I would start with the CPU.