Removing battery on Frenzy ZPU-1001

jcellegood

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I am in the process of cleaning up battery damage on my Frenzy's ZPU-1001 board. It had very moderate battery corrosion so I have removed the battery and cleaned up the corrosion. I used a vinegar solution, toothbrush and some elbow grease then followed up with an alcohol rinse. (see pics) From what I can tell, there is still continuity between the pads and the immediate elements in the circuit (R30 and GND, respectively) so I think it was caught in time before any real damage was done.

Needless to say when I put the board back in it did not work but instead showed a garbage screen (it worked before, but did not save high scores). No test beeps and the red led stays on solid. The manual says one of the possible causes is the power on reset circuit is now failing. Do I need to put a new battery back in the circuit (say a CR battery holder off the board) in order for this circuit to work? Is that likely what is preventing the board from completing it's tests?

I realize this might be an obvious/dumb question but it's been about 20 years since that one electronics course I took in college and this is my first real board repair. I want to ask before I donkey things up more than they are. :)

Thanks in advance for your help.
 

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If I add a CR2032 battery to this (3v), will that be enough voltage (the original battery was rated at 3.6v) to keep the high scores?
 
I had my wife pick up a fiberglass pen. That is really neat. I cleaned up the black traces to make sure there wasn't any corrosion left.

So then I went back and very methodically tested all the continuity in the circuit. It all seems alright. Then I tested all the diodes. It appears that a diode, CR46, is busted and has 1.6v on one side and .6v on the reverse (for some reason I can't upload the diagram I highlighted).

So we'll be stopping at the shack tomorrow and who knows, perhaps we'll be playing Frenzy tomorrow night. In any case, we'll be closer. As always thanks, you guys make it possible for me to have confidence to do this.
 
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The Replacements

jcellegood said:
Then I tested all the diodes. It appears that a diode, CR46, is busted and has 1.6v on one side and .6v on the reverse..... nope, that's not it!

Well, a week later and some parts orders arriving in the middle of the week yields some lessons. Turns out diodes, etc. measure differently than out of circuit (which I vaguely remember). So I've done some replacing (couple of diodes, transistors and a resistor) but have not yet found the culprit. I am reading a bit and learning how to use my multimeter / logic probe though :) which was part of starting this hobby in the first place.

Next weekend, we'll begin the hunt anew!
 
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