I own an old Pioneer amplifier that still works perfectly,until now! Plugged my set top box in accidentally while box was on high vol,now only left channel speaker works.Both speakers still work ok.Amp is old but trusty "SA-410".The fuse inside is intact,but no sound from r-side at all.Is there anything inside that is easily (or not so easily) replaceable? If not is it ok to connect both speakers to one channel as a last resort? (1970's old)
I had an SA 7800 until a couple of years ago; I could have cried when it finally bit the dust. That whole series was second to none. Pioneer sure was the top of the heap in those days; my how the mighty have fallen ... but I'm told that pioneer is redeeming itself with new products. I hope that's true. I hope you get your unit running again; those were/are real beauties.
Chances are you have blown in this order.. The speaker coupling fuse (usually 5 amp). The coupling capacitor..big and blue, one of a pair near the speaker socket and fuse. The amplifier 12v rail fuse..may be a black diode looking thing between the power supply ans d the output IC or the main poweramp chip (it depends on exact model..some of the very early versions used discrete components and will have 2 large transistors on a heatsink or the back of the case... If you have blown the main output chip it's most likely you can buy another full amp for less than the cost of a chip! Schematics for this amplifier are not available free.. Don't waste your money buying one, as there were at least 5 different variants of this amplifier. A good picture of the innards will help me point out some likely suspects to check, but usually a full volume blast takes out the power amp chip or transistors. Pioneer amps like trio of this vintage were not very reliable when subjected to even small transient overload.
The variable capacitor i.e vol control,is starting to get that crackling sound when it is adjusted (forget the term).So probably worth replacing anyway.Amazingly everything in that Pioneer system was good quality build-wise.The tape deck "CT-200"still reproduces a better sound for recoring to tape than most new stuff I've tried.
That "crackling" sound in the volume pot can probably be fixed without replacing it ... just get a can of "contact cleaner" from radio shack or a similar store. Just be sure to follow the directions and you can't go wrong. In fact, I'd use it on your balance and selector knobs as well. The contacts get dirty over the years .. even moreso on older units like that which put out quite a lot of heat. Janrocks seems to know her stuff; I'm sure she could explain better than me.
Was hoping either poster would reply, as other forums I have had similar tech issues posted with,replies have usually come back sounding informed but no answer in their contents.I have a can of Selleys ezyglide which is an alternative to wd-40.It's clear based & claims to be non oily & doesn't attract dirt.Can has no contents description but sounds like the properties you have mentioned.! ?
Sorry for late response...work things... :-( Whatever you do don't spray that in the volume control.. You need Super Servisol (the magic spray) which is conductive, http://www.arcticcorsair.f9.co.uk/audio/kit/superservisol.html and also contains a dry lubricant (teflon based I think). The other option is to carefully disasemble the control and run a soft pencil 4B or softer around the black resistance tracks. Check that the prongs on the rotating part are clean and not too badly worn. If they are broken it's better to replace the full control. The final check are the two contact rings which connect to the centre tags. They should be cleaned (if possible) on the contact surfaces with brasso or similar, and then given a very light smear of Lithium conductive electronic grease...All in all, it's probably easier and cheaper for one component to replace it if both channels are now working. Somewhere else you might find useful http://www.repairfaq.org/REPAIR/F_audiofaqa.html In my past I have been a professional sound and lighting engineer.. At one point running a business that could set up, run and pull down a sound rig of 60.000 watts weighing in at close to 28 tons in one day!
The ezyglide spray "is" a dry lubricant,but wont apply it if u know the product I described wont be suitable.Otherwise I have a bottle of fine graphite I can use as the whole system is still in new condition.
Yup..looked it up and ezyglide is most certainly not suitable for this job.. servisol is the stuff.. A can will last years, and it's great for skateboard bearings and all that kind of thing. The pencil method dates back to my cheapskate tube amp repairing days on the road with rock bands. Graphite powder probably won't get where you need it and could make matters worse.
