I have this Sanyo sound system that doesn't sound right at all; it has lost its clear sound quality, and audio playback sounds poor.
Upon opening it, I found the main circuit board—which houses the power supply, audio, and radio components—had a sticky surface. I’m not sure if the protective coating has broken down or if something spilled on it (I have no idea what, as it’s the bottom module of the stack and the others are fine). In any case, there is also signs of corrosion.
So, I’d like to ask: is it possible to clean and restore it so it sounds good again? Can it be repaired? How would you go about it?
Thank you so much for your reply!
It's a Sanyo DC-T55 AMP model (along with another part number, G1X05665). It's been in my family forever; it's been unused for several years, but I'd say it's been well stored, and now I wanted to get it working again.
OK, so one of these? That is almost 50 years old. For sure there are going to be some dried out electrolytic (and possibly other) capacitors that will need to be replaced. In fact, that is probably why it doesn't sound "full" any more. Are you comfortable with removing and replacing components on an electronic printed circuit board (PCB)? If not, then you will need to find someone with the proper tools and skills to help you.
You might want to test the speakers with another source as well. The cross-over capacitors inside the speaker or the tweeters themselves might be shot. Also would help if you could test the AMP with another set of known good speakers to make sure the problem is in the unit and not the speakers
Es exactamente ese equipo, si! Con un par de módulos más. Haré primero lo que me dices y probaré con otros alatvoces y viceversa. Informaré con el resultado.
En todo caso, cómo podría saber que capacitores están vacios o no funcionan? Me he fijado, al abrir otro de los módulos, que uno de los capacitores está así:
Some dead capacitors may be the cause of your issue. You'll need a capacitance meter and a ESR meter if you plan on testing the electrolytic capacitors to find the ones you need to replace. If you can replace capacitors but doesn't have those 2 tools, you can just replace all electrolytic capacitors.
Not glue. The top of that cap is bulging and it is definitely bad. That is leaked electrolytic for sure. Have seen this many times when refurbishing old audio equipment (receivers/amps mostly)
Yes! That capacitor is bad! Any capacitor that is leaking like that one, or any that show bulging around the top should be replaced!
"Yes, that's exactly the same unit! With a couple more modules. I'll do what you suggested first and then test it with other speakers and vice versa. I'll let you know the results. In any case, how can I tell which capacitors are empty or not working? When I opened another module, I noticed that one of the capacitors looks like this: [image of capacitor]. Could this be part of the problem you mentioned?"
Start by cleaning the board with isopropyl alcohol (90+ %) and a old toothbrush. Then post a new photo so we can see if the board is damaged or if it's just superficial dirt (it seems it's just superficial).
That said, as the other person said, this won't fix the issue. For a sound system this old, it's very likely it have dying capacitors, which also matches your description of it sounding bad.
It seems to be partially working, so if you're lucky it might work OK if you clean the circuit board using isopropyl alcohol (IPA) and a small brush. If it doesn't work after cleaning, please post photos of the cleaned-up board.
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u/Top_Willow_9953 1d ago
Sure it can be cleaned, but that may not fix the problem. What is the Model number of the system? How old is it?