Sanyo VTC-5150 Power Supply Problem

[Burhan_Noob]

Hey guys! I am trying to repair this Betacord VCR. I bought it on ebay and it worked for 20 minutes before it made a clicking sound and shut off, not coming back on again. So i poped the cover off to look at the PSU. And the fuse burned out. So i bought a box of new fuses. They were T 315mA 250V just like the original one. And every time i plug the mains plug in the wall, it blows the fuse instantly. I tried it 2 times. Any troubleshooting ideas? I uploaded some pictures of the board. Thanks for any suggestions



Edit: So i tried bridging the fuse and the VCR worked normally. Everything worked just fine for the 20 seconds i plugged it in. I also tried soldering 2 315ma 250v fuses together in parallel and the VCR worked fine also. I checked every board and nothing was getting warm or hot and it didn't smell burned.

 

[Bud_J]

I wonder if the wrong fuse was in there in the first place?

Either way, I'd take my VOM and measure the current going thru the fuse. I'd be curious. If it's just a *little* out of spec, it could be weary diodes or transistors maybe drawing a bit more than originally designed for. Maybe add some heat sink if so.

If you decide to run it as is, maybe put in a slow-blow fuse 10% higher than what it's actually drawing at the moment. That way, if a transistor or diode shorts out, or if something else starts pulling even more current, then the fuse will save you from having to replace too many parts.

Keep us posted!

Peace,
Bud

 

[Burhan_Noob]

Hi! Sorry for the late Reply. I found the service manual online and replaced 2 capacitors. Now the VCR works with just a singe fuse. But i still have the problem that it won't go in to the ON mode, it's stuck in standby. It's not giving me a test picture on the RF out when i flip the switch on the back. And if i insert a cassette (i finally got 2 big boxes full of beta cassettes yesterday) nothing happens even if i push the buttons. I forgot to say that that the transistor on picture 2 was getting REALLY hot! That can't be normal if the VCR isn't doing anything. Any ideas on that? Here is the link to the service manual: https://www.dropbox.com/s/wkhbrbrzmsoemcb/sanyo_vtc5000_sm.pdf?dl=0