Battle zone has loud transformer hum and is not playing

JordanT

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Battle zone has loud transformer hum and is not playing

Bought a battle zone caberet

when plugged in the start light led stays on solid nothing is on the monitor and the main transformer is humming loudly

disconnecting the pcbs (pcb power leds on) it appears to be a problem with the regulator/audio 2 board a035435

when that board is disconnected the transformer is humming normally

iv already replaced the main voltage regulator on it fixed nothing
cap kit is on it's way r29 resistor is a bit burned but it's valu is fine

the caps are original

any idea whats blown or shorting?
 
Check and/or replace the big blue capacitor on the power brick first.

Measure the AC ripple voltage on the 10.3V lines coming out of the brick, without the AR connected. If its more than 0.3V, replace the big blue.

If the big blue is ok, connect the AR, with no game boards or monitor connected, and measure the 5V, 12V, and -5V on the AR (5V is measured at the +SENSE test point). Measure the DC values, as well as the AC values on each. Report them here.
 
Did you test all the voltages on the ARII before you plugged the boards in? You should at least be sure that your +5V is OK before everything else.
 
Thanks for the help

already ordered all new caps for it including the big blue
yes i wasted no time disconnecting the pcbs don't want them to fry

interesting hearing the big blue theory have you had a big blue cause something like this before?
 
interesting hearing the big blue theory have you had a big blue cause something like this before?



Yes, I've had a couple of bad ones, which I've been able to confirm with a cap meter. (They didn't read a dead short, but showed a very low capacitance.) Just had one last week actually, which was why this looked familiar.

They aren't that common, but they do happen, and can cause the behavior you're describing. (Though they're not the only things that can cause that.)
 
Thanks for the help

already ordered all new caps for it including the big blue
yes i wasted no time disconnecting the pcbs don't want them to fry

interesting hearing the big blue theory have you had a big blue cause something like this before?

Ive seen them make the machine hum or make the monitor look outta whack when
they go bad or defective.
 
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