Hi all,
First post on the forum, so hope I get it all right - I'm trying to repair a Sony DAVS-800 home theatre system which went dead a while ago (12 months or so).
How it happened - stopped all of a sudden, no power, no power lamp, nothing works. There was no smoke or sound, just didn't power on at some point. I checked the fuse (presumably AC, the usual see-through small glass cylinder one), it was OK (don't know if it has another (DC) fuse or not), so I left it for a while.
Looking at fixing it today, so I checked a few things:
- The unit still shows no sign of life when plugged in and powered on, except:
- A small/short high pitch noise comes from it for the first few seconds after power button is pressed
- AC current does get to the fuse, power switch is OK (AC voltmeter shows 223V)
- Last thing I checked - one of the two DC power outputs shows a current (29V) so PSU is not entirely dead (this was my first thought, something in the PSU)
- A large 400v capacitor on the power board has a very slight bulge in it, but did produce a big spark when I shorted it, isn't shorted when measured for resistance, and if Ohm-meter is held to it the resistance increases, making me think it's not the (obvious) cause
Apart from this, I've managed to find a service manual for it (can't attach it due to size but will email it if anyone wants to/has the time to have a look), and took a few pics which might help (these are attached, will take more if needed).
Would anyone know what I should look into next? (I have checked a few capacitors and diodes on the PS board and most seem OK, except for one diode and one capacitor which seemed to be shorted - but it was an on-circuit test so no idea if they are really faulty or not (both are OK visually).
This sort of thing was a hobby of mine in early teenage years, so am quite happy to fiddle with it, can solder etc, but don't have many thoughts on what exactly to check next
All help much appreciated,
Best regards,
Petar
First post on the forum, so hope I get it all right - I'm trying to repair a Sony DAVS-800 home theatre system which went dead a while ago (12 months or so).
How it happened - stopped all of a sudden, no power, no power lamp, nothing works. There was no smoke or sound, just didn't power on at some point. I checked the fuse (presumably AC, the usual see-through small glass cylinder one), it was OK (don't know if it has another (DC) fuse or not), so I left it for a while.
Looking at fixing it today, so I checked a few things:
- The unit still shows no sign of life when plugged in and powered on, except:
- A small/short high pitch noise comes from it for the first few seconds after power button is pressed
- AC current does get to the fuse, power switch is OK (AC voltmeter shows 223V)
- Last thing I checked - one of the two DC power outputs shows a current (29V) so PSU is not entirely dead (this was my first thought, something in the PSU)
- A large 400v capacitor on the power board has a very slight bulge in it, but did produce a big spark when I shorted it, isn't shorted when measured for resistance, and if Ohm-meter is held to it the resistance increases, making me think it's not the (obvious) cause
Apart from this, I've managed to find a service manual for it (can't attach it due to size but will email it if anyone wants to/has the time to have a look), and took a few pics which might help (these are attached, will take more if needed).
Would anyone know what I should look into next? (I have checked a few capacitors and diodes on the PS board and most seem OK, except for one diode and one capacitor which seemed to be shorted - but it was an on-circuit test so no idea if they are really faulty or not (both are OK visually).
This sort of thing was a hobby of mine in early teenage years, so am quite happy to fiddle with it, can solder etc, but don't have many thoughts on what exactly to check next
All help much appreciated,
Best regards,
Petar
Attachments
Last edited:
