Hello All,
First time poster, long time lurker. I recently bought a Pioneer SX-828 for $100 from a lady moving out of her home. She didn't know anything about it as it was her husbands and it was working "good" right up till she packed it for moving a week earlier. It was packed in the original box and had all the original documents included including the wiring diagram and cleaning cloth. I picked it up and didn't make her prove it to me or anything like that as it was clearly not her gig.
View media item 16418
Anyway, I got it home, hooked it up and powered it on. Lamps were flickering and would completely dim out after about a minute. Toggling the brightness button on and off would restore the lights but they would gradually dim after a minute to the point where the unit appeared to be off.
This is where I should have stopped but I'm a noob.
I turned the FM mode on. I could barely hear the radio station out of the Horn of my Realistic Mach One.
Once again, should have stopped here.
I flipped the Loudness lever to on. No more sound, no more lamps on even with toggling the dimmer button.
Here's what the current power sequence sounds/looks like:
1. Power on Speaker A.
2. Red STEREO lamp briefly Illuminates
3. Audible "Click", Red lamp shuts off.
4. No more functionality.
I did check the outer fuse is fine and "seated".
I opened the unit up and gave it a vacuum and took off the cover and bottom plate.
I went to the power supply board and measured the voltages on the pins as described in the wiring diagram. Here they are
Pin 2 - Actual 12.1V, Expected 12.0V
Pin 4 - Actual 4.1V, Expected 4.5V
Pin 5 - Actual 31.6V, Expected 32V
Pin 6 - Actual 31.4V, Expected 31V
Pin 7 - Actual 35.6V, Expected 35V
Pin 14 - Actual 43.5V, Expected 44V
Pin 15 - Actual -43.5, Expected -44V
None of these values seem terribly out of line to me but I'd be interested to hear other opinions.
While inside I checked connectivity of all the internal fuses and they were all ok. The one thing I did notice was one of the diodes on the board (right near the center) had 'grown' two very fine hairs, that when the unit was upside down were standing straight up, but I imagine this is a cracked diode? Could this be a problem? I have included pictures and you can see one of the hairs as a very fine black line over some white wire insulation.
Anyway, my question for the experts, where should I troubleshoot next? My background is in computer engineering and I'm pretty handy with the soldering iron and diagnostic tools so you can talk techie to me.
Thanks in advance!
First time poster, long time lurker. I recently bought a Pioneer SX-828 for $100 from a lady moving out of her home. She didn't know anything about it as it was her husbands and it was working "good" right up till she packed it for moving a week earlier. It was packed in the original box and had all the original documents included including the wiring diagram and cleaning cloth. I picked it up and didn't make her prove it to me or anything like that as it was clearly not her gig.
View media item 16418
Anyway, I got it home, hooked it up and powered it on. Lamps were flickering and would completely dim out after about a minute. Toggling the brightness button on and off would restore the lights but they would gradually dim after a minute to the point where the unit appeared to be off.
This is where I should have stopped but I'm a noob.
I turned the FM mode on. I could barely hear the radio station out of the Horn of my Realistic Mach One.
Once again, should have stopped here.
I flipped the Loudness lever to on. No more sound, no more lamps on even with toggling the dimmer button.
Here's what the current power sequence sounds/looks like:
1. Power on Speaker A.
2. Red STEREO lamp briefly Illuminates
3. Audible "Click", Red lamp shuts off.
4. No more functionality.
I did check the outer fuse is fine and "seated".
I opened the unit up and gave it a vacuum and took off the cover and bottom plate.
I went to the power supply board and measured the voltages on the pins as described in the wiring diagram. Here they are
Pin 2 - Actual 12.1V, Expected 12.0V
Pin 4 - Actual 4.1V, Expected 4.5V
Pin 5 - Actual 31.6V, Expected 32V
Pin 6 - Actual 31.4V, Expected 31V
Pin 7 - Actual 35.6V, Expected 35V
Pin 14 - Actual 43.5V, Expected 44V
Pin 15 - Actual -43.5, Expected -44V
None of these values seem terribly out of line to me but I'd be interested to hear other opinions.
While inside I checked connectivity of all the internal fuses and they were all ok. The one thing I did notice was one of the diodes on the board (right near the center) had 'grown' two very fine hairs, that when the unit was upside down were standing straight up, but I imagine this is a cracked diode? Could this be a problem? I have included pictures and you can see one of the hairs as a very fine black line over some white wire insulation.
Anyway, my question for the experts, where should I troubleshoot next? My background is in computer engineering and I'm pretty handy with the soldering iron and diagnostic tools so you can talk techie to me.
Thanks in advance!