Problems with 1968 vintage receiver

Sound Advice

By Don Lindich

Week 6, 2007

Q: I hav a Pioneer SX 700 receiver that I purchased new in 1968. Recently the left channel has become weak on all functions (phono,AM-FM, tape, etc.) To have both channels equal I have to adjust the balance to the left and I lose much fidelity. Do you have any ideas how to fix this or where I could take it in the Twin Cities to have it repaired?

-Jim Moore, Minneapolis, MN

A: I receive a lot of questions about repairing older audio gear, televisions, VCRs, etc. Before you consider repairs, you have to consider if the item is worth repairing. Most digital electronics such as surround-sound receivers, CD players and DVD players are not worth investing funds repairing unless you have a top-quality model that cost $500 or more new. Like computers, newer equipment is often (but not always) cheaper and better. A classic piece of gear such as yours is a different story though.

A potential culptit with older equipment such as yours is dust inside the receiver. Fine particles of dust work their way into the contacts of switches and volume adjustments, which can result in weakness in a channel, scratching sounds when you change volume or adjust tone, or signal drop-off in general. It sounds like yours may be in the balance control, but the culprint could be almost anywhere.

The best way to correct this is a professional cleaning at an electronics repair shop that specializes in audio. I am unfamiliar with repair centers in your home town, but you may want to check with a local specialty shop as they usually have a repair person in-house or an outside vendor they work with.

If you are willing to ship it out for repair, I have been recommending Atlas Audio Repair at for about two years and my readers using them have reported back with universal praise. They will provide a free estimate if you send equipment to them, which helps offset the shipping cost.

Before you send it out, you may want to try cleaning it yourself. All you need is some electrical contact cleaner, which comes in an aerosol can with a long thin tube that attaches to the nozzle. Unplug the receiver overnight and the next day, take the top and front cover off. (Be sure to arrange the screws as you remove them so you know where they go when you put it back together!) Use the tube to spray contact cleaner into the switches and rotary dials, then work them back and forth quickly. Do this several times for each switch. After you are finished, put the covers back on and test the receiver. If everything sounds perfect, congratulations- you fixed it! If you still hear problems but the sound is louder and clearer, you are on the right track but need to either clean it more thoroughly or have it cleaned professionally. If there is no change, then the problem lies elsewhere and you will have to have it repaired.

For the small expense of a little bit of your time and a $5 can of contact cleaner, you may want to give it a try before getting a repair or cleaning estimate. Good luck.

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