Genesis Model 2 reset switch measurements (ON/OFF)

Hey all -

I think I have a faulty reset switch on a Genesis Model 2. I do not have a spare available. I assume it has to be in circuit in order for the Genesis to work (bridge or not bridged depending on if you want the system executing or halting).

Can any of you tell me the resistances between the points or suggest a way to verify it is the reset switch that isn't working? System powers up, carts and port are clean, screen is active...but black. Seems like infinite reset or something like that to me.

Thanks!

 

Pull the rubber dome off and clean the PCB, leave it off and see if it boots

 

Thanks, ASSEMbler.

No response when touching top to bottom contacts on either side of the reset switch. Screen remains black.

 

Tried a quick pull of the rubber dome. Doesn't boot.

I did a bit of spot cleaning here and there when I first opened it up. Was there a particular area you want me to focus on cleaning, or should I huck it into the dishwasher?

 

clean the pads under the reset dome on the pcb

 

You mean the ones inside the reset switch? Cleaned up. No change.

I suppose the switch might be fine, so now I wonder where I could move next. Anything to scope or meter probe to see if the cart is talking?

 

First thing I did was check the voltage regulator and get +5v out.

 

Look for traces that might be corrupt near the VDP and also there have been other people with the black screen and one of them was a faulty Z80 processor.

 

OK. I can check that out. Any particular pin to probe on the Z80 just to see how it is doing?

Hmm. This was part of a box of "broken" items I obtained. I have been using my bench MK-2103 to test it, yet there appears to be a 1602 in the box. I wonder if the person plugged a Model 1 PS into a Model 2.

Thank you all for your replies.

 

Black screen has been ~4/4 times for me the cartridge slot - 3 fixed by cleaning it, and 1 had a broken trace between the cart slot and a nearby IC. Maybe your issue is more severe, but definitely give the slot a really good clean first imo

 

Hey, fluxcore. Thanks for the feedback.

Yeah. Did a lot of cleaning right off the bat. Cart is clean and works in other consoles. Nice, solid fit in this one. Inserted and removed cart, cleaned it again, and repeated the test. It feels like it really should just be a clean it up situation - a #1 problem and #1 easiest fix. I may have additionally reflowed some of the cart pins, but I can't remember. This one has been in the pile of repairs for awhile now - I just haven't given it top priority.

 

Odds are someone has put wrong polarity into it.