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How to fix short in older stereo?

PLEASE help me fix this problem....

I have a 70s Marantz 2225 receiver. Lately the right side speakers keeps shorting out. I have to touch/jiggle the "push-in" buttons to make it work again. (For example the buttons on left side..like the Dolby, Tape 1, Mono, Hi Filter) When the right side comes back on..it will short out again quickly. "Seems" to happen more often when the volume is louder...but not sure. It doesn't seem like one button is causing the problem as it seems to work when I jiggle most buttons...even the "push-in" buttons on the right side. No short happens when I jiggle the whole stereo or touch different connections on the back of the stereo.

So it as simple as opening it up an cleaning around the buttons or is it a situation where I need to fix/change/replace something? If it should be as simple as cleaning...how do I do that...spray, oil, brush...do I need to take the plugs out or just clean then without removing too many pieces? Is there an online video somewhere to show me how to clean them...if that is the problem.

I am a very novice guy with electrical stuff. :(


How to fix short in older stereo?

The problem is actually caused by an "open" connection. The contact closures within many of the switches become oxidized over time, and either only make a limited connection, highly resistive, or no connection at all. The switches that cause the most problems are the tape monitor switches, Mono, Dolby, Tone, and even filter switches. These switches are usually multi contact, multi pole slide switches. Some have a very small access hole on top in one or more locations, others may have an opening on the rear, others have side access holes such as in pioneers.
Most can be cleaned and deoxed using Caig products such as D-100. The can is small, gives a metered output, and comes with a thin nozzle. While the nozzle is not small enough to fit in the small access holes, you can position the nozzle directly over the hole press the trigger, and get the solution in there. Immediately after spraying, you need to rapidly exercise the switch to clean the contacts. Usually this works, but I have had to at times, remove the switch from the board, dismantle the switch, clean and polish the individual contacts, apply deox solution and reassemble for some stubborn switches. Only do this as a last resort, as it is very easy to break the metal tabs on the switch preventing reassembly.
Volume, balance and tone rotary controls should also be cleaned as they get dirty as well. I use Caig D-100, or D5 to clean these potentiometers. They at time have access holes on top, and always have holes on the bottom in between the contacts.
Last but not least, many units such as the Marantz have a speaker relay where the contacts get dirty as well. Usual symptoms are low or no volume on one side or the other, that comes on normal when you tap the relay, or power the unit off and on. This needs to have contact cleaned as well.

How to fix short in older stereo?

GREAT Feedback!!! THANKS!!!

I will get the contact cleaner before and dive in to try and fix. I hope the holes are large enough and self explanatory where they are.

I just found a good video on how to clean the relay as well.


Appreciate your time.


How to fix short in older stereo?

Remember that "less is better" You don't want to get this spray and its associated oil all over the boards. This is why I recommend caig D100 because it only releases a very small controlled amount when you press the button. Caig also makes "D5, and "D6, but these are not metered like the D100, and if you are not experienced, it is easy to spray way too much when applying.

How to fix short in older stereo?

Thanks for all your feedback. I have fixed the problem. I went out to find Deoxit as it seemed to be the holy grail on most blogs. I probably did spray too much :) I sprayed all the potmeters and push buttons while clicking and turning them. However I couldn't get the cover off the speaker relay without potentially breaking something "I" couldn't fix. So I had my fingers crossed when I put it all together. Voila...it works great. And I feel better hoping/knowing that using something as good as Deoxit versus WD40 will keep the unite working better longer. Too bad Deoxit costs over $20 in Vancouver Canada...and I won't use it often.

How to fix short in older stereo?

If you ever take a trip to NY, Deoxit cost $15 or less is some of the manhattan high end camera supply stores.
But good thing you didn't use WD40, as the petrolium chemicals in it would have destroyed your controls and switches. It is very bad on plastic.

The best way to clean the speaker relay is to desolder it, remove it, and spread the sides from the bottom by the 2 tabs, using a pair of very small screwdrivers. But as long as everything is working, leave it alone.