Yamaha A-25 / A-500 caps diagnostic

[see_what_ha]

Hello audio people. I'm a total newb in audio equipment. But the winter is long and I need to fiddle with something cool. I bought Yamaha A-25 / A-500 depending on the market amplifier at the garage sale for 15$. It is a solid state amp. Whatever that means))) there are no lamps.
Looking for some threading wisdom and advise on doing this fix the right way.
Symptoms:
1. when I got it, it was missing few screws from the top cover - someone was messing with it.
2. It powers on.
3. When I hooked up my turntable to it, it had no output whatsoever. After I pushed source selector a few times it started to play. All controls started to work afterwards. And plenty of power on output, was afraid neighbors would start to complain. Could it be that the source selector is "clogged" ? Also, I attache the image of push source selector assembly. Each selector has a little hole on top, is it for Deox to clean it?

4. From visual inspection it appears that two "main" gigantic caps are leaking. Goo at the bottom. Also see the picture attached. The amp was made in early 80's, but I'm not sure if the caps where replaced later on. Question: Is there an easy way to diagnose a cap? Is it even worth the time? Should I just replace it?

5. If I just go ahead and replace it? Any suggestions for the product to replace it (something with good quality/value balance) See picture for brand and info on caps.
6. Is it worth replacing smaller caps? None of them appear to be bloated or leaking.

Any advice or link to the info is greatly appreciated.

 

[ivandezande]

Solid states means it's transistors not tubes.

The goo is glue.

Yes clean all the controls, the relay might also be at fault and need to be replaced.

I had one and recapped it, it sure wouldn't hurt although it is newer than much of the gear discussed on this forum.

 

[ic-racer]

Welcome to dangerous levels of electricity. First off, don't believe everything you see on the internet.
Your unit is from 1982 and some might believe that is older than a lot of gear discussed on these forums. The glue holding the capacitors to the PC board is corrosive and should be removed before it causes any damage, see example picture (Yamaha A-1000).

 

[avionic]

The glue holding the capacitors to the PC board is corrosive and should be removed before it causes any damage,

Chances are more than good, That the damage has already ran its course in the past 25-30 years. If the glue was ever in contact with metallic surfaces it will cause corrosion with the right environment. ie humidity..

 

[avionic]

Welcome to AK BTW.

 

[see_what_ha]

Thanks everyone, for the responses. I will try to remove the glue. Most likely that It will not do any more damage than it already did. But why not just do it, if the unit is already gutted on the table.
On the subject of pot cleaner compound. From what I could gather online DeoxIt D5 is THE product to use. Is it worth buying a can for a single amp that I have?

 

[ivandezande]

Thanks everyone, for the responses. I will try to remove the glue. Most likely that It will not do any more damage than it already did. But why not just do it, if the unit is already gutted on the table.
On the subject of pot cleaner compound. From what I could gather online DeoxIt D5 is THE product to use. Is it worth buying a can for a single amp that I have?

Yup. D5 for switches, Faberlube for pots.

 

[avionic]

Is it worth buying a can for a single amp that I have?

Do you want to enjoy your Yamaha? Besides, next time you will have it on hand.

 

[see_what_ha]

Do you want to enjoy your Yamaha? Besides, next time you will have it on hand.

This is exactly the reason why I signed up for this forum. Good point.

 

[Binkman]

imo deoxit5 is handy anyway.. has adjustable low med high spray valve... plastic safe so if ya need a little quick shot of lube somewhere..