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Power supply problem on Orion DVCR2002 VCR/DVD combo

The unit doesn't have power. I found two diodes (in parallel) on the power supply board seem got burnt (burn mark on the PCB). Took the diodes off the board, one is dead (zero resistance). The other one seems to work. I replaced the dead one with a light emitting diode (that's the one have handy, ok :-)). Plug the unit in and it has power to show display on panel and disc tray works. I put a disc in and closed the tray, after spinning for a few seconds, the other diods (not the one I put in) over heat and burnt (smoke). The PCB close to the diodes is a kind of separated from the board, looks like from overheating.

One other thing. The largest capacitor has some whitish stuff sticks to it (it is dry though). I wonder if it came from the capacitor, or it was put there on purpose. The cap of the capacitor looks flat and good.

I don't have much electronics repair experiences and hope to get some guidance here. What should I look for? How to test if the capacitor is good or bad (I only have a multimeter).

Thanks a lot in advance!

Reply to
allabouturns
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The white stuff on thte cap is probably glue. You need to test all of the components in the power supply, and replace them with equivalent parts, not just what you have handy. You will need an ESR meter to test the capacitors. Once you replace all the bad components in the power supply, the unit should power on again, but if you miss just one bad part, it could cause a cascade failure of many parts, including any you may have changed.

Reply to
Jumpster Jiver

Diode OK til motor spins, probably a bad spindle motor (shorted). Pretty common problem.

Mark Z.

Reply to
Mark D. Zacharias

Do your professionals test all components :-)? I was hoping this is an easier fix. Do you have a more specific suggestion?

Thanks.

Reply to
blueking

The motor did spin. Will that still be a spin motor problem? One fact is that the diodes got hot even when the motor doesn't spin. Any other suggestions? Thanks a lot.

Reply to
blueking

Are you really saying that you replaced a power supply diode with an LED?!?

...that's amazing.

Reply to
Mr. Land

Why is it so amazing? Isn't the LED a diode that emits light? It only took a genius like me to figure that out :-).

Seriously, it worked, well briefly. But it looks like the overheat of the diodes were caused by some other problems because the LED is also pretty hot (without motor spinning).

Please keep suggestions coming in. I hope this is not too complicated problem.

Thanks again to all the pros!

Reply to
blueking

What often happens is that the motor is shorted through 1/2 it's rotation. This means the motor spins weakly, and draws LOTS of current. If the motor happens to be stopped on the shorted phase, and if it's really short-shorted, meaning 0 ohms instead of 1 or 2 ohms maybe, then the motor won't go until you "help' it along.

Mark Z.

Reply to
Mark D. Zacharias

Thanks Mark.

I tried to unplug the power to the disc loader. The LED still got hot. So, I think there is something else that's not working right. How should I take the next step?

By the way, if something is short, shouldn't the fuse break instead of the diodes? The fuse is fine.

Thanks again.

Reply to
blueking

It's amazing because a power supply diode is usually designed to handle a lot of current (like 2, 3 or more amps), while an LED is usually designed in just the opposite way, that is, to operate with a minimal amount of current passing through it. (like 10 mA). You stated that there was heat discoloration on the PCB near the diodes - that indicates that they ran hot, which usually means they carry a lot of current during the normal operation of the circuit (are are likely designed that way).

The fact, then, that you were able to replace one of these devices with an LED, apply power, and not have the LED instantly explode is...well...amazing.

Reply to
Mr. Land

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