Sony SLV-E780 Power Supply Issue – Clicking Sound, Need Help Identifying Faulty Component

[Akuanka]

Hi everyone,

I'm troubleshooting a power supply issue with a Sony SLV-E780 VCR. The device clicks repeatedly but doesn't power up completely. I've already replaced five capacitors, but the problem persists.

Here's a video link https://photos.app.goo.gl/3Xki6yvCLn67gLX78 showcasing the sound. Based on your experience, could this be due to a transformer, diode, or another component? Any guidance on what to test or replace next would be greatly appreciated.

Thanks in advance for your help!

[R_J]

Check the secondary voltages, are you getting any voltage at all on any of the secondary diodes? You should have +6vdc on PS202 fuse, if not, check for a shorted diode in the secondary.

You replaced 5 capacitors? I guess you did not replace the bad ones, which ones did you replace? there are location numbers beside each capacitor ie Cxxx , also try replacing C154, C153 & C261, if that doesn't help, replace C253, C202.

[R_J]

Check the secondary voltages, are you getting any voltage at all on any of the secondary diodes? You should have +6vdc on PS202 fuse, if not, check for a shorted diode in the secondary.

You replaced 5 capacitors? I guess you did not replace the bad ones, which ones did you replace? there are location numbers beside each capacitor ie Cxxx , also try replacing C154, C153 & C261, if that doesn't help, replace C253, C202.

[Akuanka]

Check the secondary voltages, are you getting any voltage at all on any of the secondary diodes? You should have +6vdc on PS202 fuse, if not, check for a shorted diode in the secondary.

You replaced 5 capacitors? I guess you did not replace the bad ones, which ones did you replace? there are location numbers beside each capacitor ie Cxxx , also try replacing C154, C153 & C261, if that doesn't help, replace C253, C202.

Hi R-J, thanks for quick reply. I have checked or replaced all electrolithic capacitors, still same issue with tickling sound. Now I wanted to check voltage on secondary but where to check it? I do not see any 2nd fuse, just for 220v. I am attaching photo. thanks in advance. Is that possible to check diodes when they are still soldered to the plate? Sorry, I am beginner in this matter but learn quickly.

Just checked and there is no ac 220v voltage on the primary fuse which I do not understand why as well as no voltage on secondary. I found 2 contacts showing 6v on the back of pcb

[Akuanka]

Here are more photos

[R_J]

Check for 220v right at the plug going to the board, maybe your a/c cord is bad? Get the service manual so you can look at the schematic of the power supply.
The only secondary voltage you will see at CN201 is the D6v standby; to check the other voltages you need to have the power supply connected to the vcr or check the other voltages on the cathode of D251, D252 and D263, on D254 Anode, you can check for negative -12v

[Akuanka]

no, cable is OK since I hear tickling sound. There was also smoke coming from the board last time I connected it to 220vAC. I have taken it out of VCR. So the only way to check diodes is to power it up? Is there a way to check disconnected from AC and in the board or I need to solder them out one by one?

[R_J]

You can check the diodes with power disconnected using your meter in diode test mode. What smoked? I would find out what smoked and repair that before continuing.
The ticking sound you hear is likely the power supply trying to start but is seeing a short in the secondary and shuts down and retries

[Akuanka]

Now I tried to power it again and there is no smoke any longer but still ticking. So is it definitely secondary? PS is one bigger board and on top of that there is smaller board. Is this smaller board secondary circuit?

[R_J]

Whatever component smoked, likely a resistor that is now open circuit. Just because it is no longer smoking does not mean it fixed itself.

[Akuanka]

thanks. Primary or secondary circuit? is secondary on the small board or main PS board? The name of PS is mitsumi sr825

[R_J]

There was also smoke coming from the board last time I connected it to 220vAC

What did you do to cause the smoke to come out? did you short something? install a capacitor backwards? power supplies do not smoke for no reason

check these diodes

[Akuanka]

Hi, you were righ. I installed C208 wrongly and C201 is missing completely. By the way do you know the type of C201 in terms of uF and V?

[R_J]

Here is the service manual C201 is 220µf/16v
C208 is off the Power Cont1 pin, having it in backwards should not cause the problem you are having.

[Akuanka]

I remember C208 was 470 uF 10V and I dont have such cap so can I put 470 uF 16v instead?