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Pioneer sx 550..issues..

Posted: 12 Feb 2019 16:05
by Iloveali
Found a sx 550 for 20 bucks, cosmetically it's pretty good, the knob for power is broken off and half the shaft. Seller says when he turns it on the lights flicker but that's it.. that's all I know, i was thinking maybe it's a fuse issue? Anybody know where I might look for the fusses for a sx 550? And also what fuses am I looking for. Be sweet to get the thing running. It should I just pass on it? Already have a good sx 780, thought it might be a neat project. Anybody like the 550's

Re: Pioneer sx 550..issues..

Posted: 12 Feb 2019 20:04
by musicmn
Hi, I'm running and SX 550 in one of my set ups it a very nice 25 watt pre channel or so receiver. The one I own had very distorted sound on both channels above the number two volume setting. It turned out that the entire receiver needed to be rebuilt. All the caps were bad even the main filter caps. Also a bunch of resistors and some transistors were bad and needed replacing. The tech I take my equipment to is a very good friend so I trust his knowledge on these things. One thing he told me that is a very common issue with these receivers are the on/off switch. The contacts used in these switches where you go from ON to speaker A or speaker B or speaker AB burn very badly over time. These contacts cannot be cleaned the entire switch needs to be replaced but it sounds like that's something you will need to do anyway. My tech was able to find a NOS switch on Ebay and installed it on my receiver. He put some type of transistor in line with the switch that takes the load of the power coming into the switch so the contacts will never burn again. He told me he read about this online because these type of power switches were used in a lot of different models by various makers and they all seem to have this problem. If you want I can ask him what type of transistor he used or the article where he found the info the next time I talk to him. I want to add that one symptom of the power switch being bad is that the lamps flicker on and off that's what he told me. I hope this helps.