Hi All,
I bought this old Pioneer a while ago to learn about fixing amps and practice soldering on. It had constant crackling and popping through both left/right channels and both A and B speaker outputs and one dead channel. Cleaning the balance pot sorted the dead channel simple enough. I replaced all of the easily identifiable caps bit by bit and the crackling got better and worse and went away and got worse and got better as i went...kept at it, running out of time/money and then coming back every couple of months.It is pretty good now but still crackles a bit mostly before it warms up. I really just want to get it finished. There are four pale blue caps, two of which buzz and crackle when touched and I suspect if I could replace them it would make all the difference but they don't have farad or volt ratings on the jackets.
If there is anyone out there who has recapped one of these units or who recognises these caps I would be very grateful for your help. A schematic would be great, I can't read them but I plan to learn that too so what better time?
These are the blue caps they are Sanyo and the jacket reads M509 on one side and 1/25 on the other
Also these clear plastic caps with pink jacket that reads 6800J WV.50
I promised myself that I would not do anymore work on the aesthetics until I got the thing sounding better but for those who are interested I have sanded back and rusted up the cover and all the knobs were missing so I have corks on the front for now. I will eventually make some nice nobs out of a red wood and switches out of cow bone and stencil controls over the front. The corks look pretty daggy (that's Oztralian for not real good) so I won't post pics just yet...
I bought this old Pioneer a while ago to learn about fixing amps and practice soldering on. It had constant crackling and popping through both left/right channels and both A and B speaker outputs and one dead channel. Cleaning the balance pot sorted the dead channel simple enough. I replaced all of the easily identifiable caps bit by bit and the crackling got better and worse and went away and got worse and got better as i went...kept at it, running out of time/money and then coming back every couple of months.It is pretty good now but still crackles a bit mostly before it warms up. I really just want to get it finished. There are four pale blue caps, two of which buzz and crackle when touched and I suspect if I could replace them it would make all the difference but they don't have farad or volt ratings on the jackets.
If there is anyone out there who has recapped one of these units or who recognises these caps I would be very grateful for your help. A schematic would be great, I can't read them but I plan to learn that too so what better time?
These are the blue caps they are Sanyo and the jacket reads M509 on one side and 1/25 on the other
Also these clear plastic caps with pink jacket that reads 6800J WV.50
I promised myself that I would not do anymore work on the aesthetics until I got the thing sounding better but for those who are interested I have sanded back and rusted up the cover and all the knobs were missing so I have corks on the front for now. I will eventually make some nice nobs out of a red wood and switches out of cow bone and stencil controls over the front. The corks look pretty daggy (that's Oztralian for not real good) so I won't post pics just yet...
the blue one is an electrolytic and changing it will probably help ...that will be 1mf/25 volt .... then dont second think about it .... all electrolytics in old machines need to be replaced ...
the other capacitor is 6800pf and its a mica solid state part doesnt need to be replaced
some more info can be found here http://www.diyaudio.com/forums/solid-state/136261-vintage-amplifier-repair-upgrade-manual.html
regards sakis
the other capacitor is 6800pf and its a mica solid state part doesnt need to be replaced
some more info can be found here http://www.diyaudio.com/forums/solid-state/136261-vintage-amplifier-repair-upgrade-manual.html
regards sakis
I'd also recommend that you try and clean the dust off the board. Dust is hygroscopic (attracts water) and if you live an area with high humidity you may just find that suddenly on a "wet" day that all your replacing of those electrolytic caps and more have gone up in a flash due to a flash-over between two components.
Don't ask how I know about this. Computer PSU's are notorious for doing just that "poof" at switch-on and that stench...
Don't ask how I know about this. Computer PSU's are notorious for doing just that "poof" at switch-on and that stench...
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