The manufacturer seems to have web site, but I infer that's not an attractive path?
Any date markings? The Dallas chip suggests it's not a new instrument. Again, I think you need a scope to poke around, and ideally a friend with some experience.
P.S.
Added thoughts: You might poke around with your voltmeter at the keypad pins to see if you can see any activity. A meter is a very slow tool, but maybe you'll see something. The idea is to get some encouragement that the processor and software isn't frozen. You're in rough territory. Good luck!
Any date markings? The Dallas chip suggests it's not a new instrument. Again, I think you need a scope to poke around, and ideally a friend with some experience.
P.S.
Added thoughts: You might poke around with your voltmeter at the keypad pins to see if you can see any activity. A meter is a very slow tool, but maybe you'll see something. The idea is to get some encouragement that the processor and software isn't frozen. You're in rough territory. Good luck!
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The rubber pads (Black thingies) should be conductive.
Each of the comb tracks to connector also.
Conductive means less than 10 ohms max.
When the pad touches the comb like tracks, it connects the matrix, row and column, and the IC takes it from there.
For this work, a continuity tester, meter set on beep, those are handy.
Analog meter too, sometimes digital is slow.
Each of the comb tracks to connector also.
Conductive means less than 10 ohms max.
When the pad touches the comb like tracks, it connects the matrix, row and column, and the IC takes it from there.
For this work, a continuity tester, meter set on beep, those are handy.
Analog meter too, sometimes digital is slow.
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So the device doesn't start up at all. The way you describe it it hangs in POST, so naturally the buttons don't respond.
I would first clean out all the dust and then check if the IC's make good contact in their sockets. When in doubt carefully remove them, clean all the contacts and refit them.
If that doesn't work, check if all the voltages of the PSU are present. I suspect you'd need to see +5V and perhaps +12V at least.