Issues with power on reset?

[Geoff Oltmans]

Do 99/4As generally suffer from power up reset issues? Namely when turning on the console do they sometimes not initialize to the splash screen the first try? The console I've got now does this, a subsequent power down/up usually takes care of it and seems like my old console from many years back also did this.

[jrhodes]

I had that issue, but only with a cartridge plugged in. Turned out to be flakey connection on the grom cart-port daughter board. Took machine apart, unplugged the grom cart-port daughter board from the main mother board and cleaned the contracts. Also removed the felt pad on the cartridge side of the port.

[HOME AUTOMATION]

Noisy power switch? Try to replicate using wall plug.

[Geoff Oltmans]

I used some contact cleaner on the power switch thinking that might be it. I’ll try with the power plug that’s a good idea.

[matthew180]

The PoR (power-on reset) for the 99/4A console is fine by itself.  The problem is that the PoR circuit has a connection to the cartridge port, which was intended to reset the console any time a cartridge is inserted.  Unfortunately in practice this can cause problems, and not all cartridges get their internal electronics right (especially since negative voltages are involved, it is a very confusing affair).

 

There is also the problem that the forward-facing cartridge connector is really an L-adapter to the motherboard, which is two more connector interfaces to get dirty and/or wear out over the years.