JVC HM-DH30000U power issues?
 

hello I recently purchased a JVC DVHS and I'm having issues with the power supply.
when I got it I plugged it in and the fan spun really slowly and then would shut down. no other signs of life. I opened the power supply up and 2 caps had leaked out the top so I swapped all the ones that I had in stock.

there was a 50v and a 100v cap I don't have to swap with. now the fan spins faster and 2 green light turn on and then turn off but I have no screen or power.

I'm getting about -24v on the -29v line but I have -12 on the dc+ and dc- rails. and I'm pretty sure that's supposed to be 3.5v

i have the service manual for it but power supply's confuse me a bit.

Check the power regulators, they tend to go bad if the associated caps leak and short out.

ill check them. I suppose the output pin should be its listed voltage.

im not seeing a regulator listed on the DC+ pin on the schematic so I'm a bit confused how that voltage is being generated.


is this the correct replacement power supply?
https://www.ued.net/ued/viewItemActi...CLPA10118-02B1

Always start from the transformer and walk your way to the outputs to the main chassis board, whereever the voltage is not reading correctly go back and check the component up stream, It does require some circuit diagram knowledge, The service manual does not show you how to troublshoot, it just gives you standard check procedures to help you identify the problem assuming that you know what to look for.

i checked my voltages and all the regulators are outputting there voltage as long as the fan is running. the power supply seems to shutdown after a few seconds. my -29 is only -21 and at the display it drops to -12. it drops after d7011. dc+ and dc- still have -12volts on them but im not sure how that is generated it doesnt seem to be connected to any regulators as far as i can see on the schematic.

I'm starting to think the transformer may be bad? the dc+ and dc- end up coming from pins 10 and 11 off the transformer.

at this point i have -12v on both pins.

the rest of the power supply seems to be outputting the correct voltage but it seems to be shutting down i have no screen no power and no loader movement. but the fan will spin at full speed for a few seconds. sometimes longer.

The transformer itself outputs are AC not DC you shouldn't get any (-) if you are using the meter in AC mode.

I was using an oscilloscope. All other pins had a high frequency waveform except pins 10 and 11 just a flat -10-12 volts