How do you power cycle?
Turning the game off and on, off and on quickly and sometimes you can "fool" it into thinking there's batteries installed.
However, here's how to check if you got battery power to your 5101 RAM chip which, in mine, I had the same issue as you. I replaced it and the game booted. With the game off, using your DMM put it in DC voltage, ground the black wire, put the red on the right side of the diode directly above the 5101 chip. Should be getting somewhere around 4.3 volts. Now test the left side. Should be a drop off to around 3.9 volts. Now check the top all the way left pin of the 5101 chip. Should be getting the 3.9 or so volts you got at the left side of the diode above. That means the chip is getting the battery power. Remember, voltages are appx. depending on how good the batteries are. If you don't get the drop off in voltage that diode is probably bad but the RAM is more than likely your issue.
Also, if you battery holder is shot or there's a cracked trace somewhere between them and the diode, that could cause the same issue. Nonetheless, if you're getting 3.9 or so volts at the top all the way left pin of the 5101 chip than, the chip is probably shot. Order new one from Great Plains or Marco's.
Note, DO NOT install your new one like I did. Socket it. I was impatient and soldered it to the board. Not very well I might add. I was inexperienced with chip removal as I had never done it before. I have improved dramatically since then and will deal with the new 5101 if it ever becomes an issue.
Be careful with desoldering the legs. It's easy to damage the plated through holes, especially on the front of the board which should be avoided with the iron as much as possible. Keep your iron's temp as low as necessary.
When installing the new chip, notch will be towards the left.
I've added some photos to help.
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