Hi everyone, I purchased a CF-580 locally in the twin cities that was in really rough condition. Here’s a YouTube video I made: I cleaned it up, and deoxited all of the switches, sliders, and pots. Unfortunately, it seems like I have a problem with the amplifier section. Both channels distorted, and left channel is low volume. I tried FM as well as auxiliary in. Same audio issues on both. I’ve done mild to moderate restorations on Walkmans and solid state / tube HiFi for a number of years. After opening this unit up, I’m questioning whether I really want to embark on this. My fundamental challenge is components are so tight that I’m struggling following signal path from the schematic. Back side traces a bit hard to follow as well. Neither impossible, just not as easy as an old receiver. I have both a signal generator and an old (restored and working) Eico 147A signal tracer so theoretically can put a signal in the aux in but tracing component to component seems daunting. I don’t generally like giving up before I even start, so wondering if anyone has advice on a quick scope or signal trace excercise? There are a TON of caps, which I can shotgun replace but that seems both harsh and overwhelming. I attached a couple of pics of inside to add to the YouTube video. Any thoughts greatly appreciated! Mark
I have the smaller CF-550 and had to replace every single electrolytic capacitor in the entire machine. Hard work? Yes. A labor of love. Maybe you have already seen my thread on the subject. There was also a transistor causing crackle on the left channel. Ordered some modern equivalents and ended up replaced 16. Yes the board is packed. Yes it is tough. But by working on the board on it's side and still wired in... one can see both sides of the board... and find the pins to the capacitor or transistor. By feel and intuition eventually. Precision tinned "wet" soldering tip... one pin at a time melt and carefully wiggle free. Clean everything including the solder tip. Put in the new part. New solder applied and flowing onto the pad. Clean again. Check correct polarity for the 10th time. Move on to the next one. Brutal. But I was a mad man driven with such an obsession I somehow overcame it CrAzY, I don't know what got into me, not doing that again anytime soon! These old Sony boxes are so well built and so heavy... and they cost such a lot of $$$ back in the 70's. $400 for the CF-580 in 1976 adjusts to well over $2000 today. And the style is just awesome If you love the looks and incredible build quality... bit by bit... little by little... replace those capacitors with good Nichicon audio caps.
Definitely a very nice radio. A good score for the price! Cleaning the outside of this one is quite easy. You can remove all the exterior panels and then wash it in the bathtub with plenty of soap. It's definitely worth repairing. Sending a signal into it and then tracing it with the scope to see where the problem lies seems like the best first step. I have two of these, and both still work fine with the original capacitors. So replacing everything at once isn't always necessary with this model. It is extremely labor intensive! The service manual for this model is also available, so checking the voltages is also possible. But I would start with tracing. It would be nice to see pictures when it's finished
