Yamaha R-5 Receiver

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Hi.

I have a problem with an Yamaha R-5 Receiver. The sound disappears sometimes. When looking at the capacitors in the power supply, i notice a lot of electrolyte have leaked out and ruined some shorts and resistors in the nearby area.

Every now and then the relay RY101 clicks. The owner tells me the sound comes and goes and i guess this whenever the relay switches on/off.

Does anyone have a service manual / schematic for this receiver or can point me in the correct direction? 🙂

Thanks in advance.

Sham.-
 
You need to measure the voltage from each power amplifier. If the voltage is more than a fraction of a Volt with no signal, you need to adjust the offset. Yes you need a manual to do it properly. Excessive offset results in the protection circuitry opening the speaker circuit by deenergizing the relay.
 
So you think the offset is the main problem? DC on the output? I will check this as soon as i can find a schematic. 🙂

However, the main capacitors (2x6800uF) have leaked and ruined the components around them. Some of the resistors barely have any copper legs left. 🙂

Sham.-
 
Sorry for double-posting, but for some odd reason i can't find any way to edit my previous post.

Some solderings of the legs of the relay had broke, and so had several others in the amplifier as well. Not only is this an old amplifier, but it have been moved around a lot as well. After re-soldering the relay, the amplififer switched successfully on after exactly 5 seconds each time and didn't fail for about an hour or so testing. About 50-70 soldering points later, i was satisfied. I have ordered replacements of the main capacitors for the rectifier cirquit, and i have the resistors already so i'm replacing the components that show sign of damage to be sure.

The amplifier belongs to a friend of mine and is considered a family clenodium so i want to make sure it's in good condition when i return it. 🙂

Thanks for the reply anyways, any reply is appreciated. 🙂

Sham.-
 
Sounds like you are on the right track. Once you replace the PSU caps you should be OK, since it seems to work a bit after an initial delay. Let us know if there are still problems after replacing the main caps.

Another thing to consider is replacing the other electrolytic caps. They don't get the stresses that the main filter caps, but may have degraded over time.

The relay s probably the speaker protection circuit, tripping when DC offset gets too high due to the rails being off because of bad main caps.
 
I am new here and since I found this thread on the Yamaha R-5 already going, I am posting my question here for help. I acquired recently this receiver R-5 in very good shape, everything works fine except it will not keep the stations set to memory. After I turn it off for a couple off hours, the memory gets erased. For short periods of being turned off, the memory is still there just fine. I wonder if there is some sort of battery that needs replacing or what. Any help will be appreciated.
 
Thanks for this thread. I had the same problem with an R5, and the cause was also leaky/degraded caps, and corroded jumpers. Replacing the 3 large caps and the jumpers did the trick. Looks like I'm good for another 30 years.
 
It should actually be the old fixing glue that's the problem. You may have noticed it's discolored. That stuff absorbs moisture and becomes acidic and hence corrosive, a well-known issue in Yamaha's power amps from the time (along with a lot of bad solder joints). You need to remove all of it to be safe.
 
Yes, the corrosion did seem to be associated with the dark red glue. The smaller of the three cap was leaking out the top too. It looks like the corrosion created an open circuit, but the cap was going to fail soon too.
 
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