Rotel RA-11

[HRmeteohub]

Hi!

This Rotel RA-11 integrated amp is really young for my standards, but it developed a nasty problem with potentiometer. No matter how you handle it, the volume was changing erratically. So, a hefty dose of compressed air, brush, some Kontakt spray and other tools were needed to get the amp back in order again. Easy fix, cleansing took an hour and repair of the encoder (potentiometer is digital - yuck) took about 20 minutes.

Here are the pics and videos.
Before:

 

[HRmeteohub]

... more images...


THIS solder marks were cleansed before it was put back!



Finally, how it worked - before

and after

So, there it is. Quick fix.

 

[fyj2972]

Good job, I have seen those type encoder issues , Some times You can find them used in Tuner. Dirty one will cause tuning frequency changing erectly.

 

[fyj2972]

You still can find some type rotary encoder from Digikey, Mouser, newark etc.
https://www.newark.com/c/sensors-transducers/encoders/rotary-encoders#

I like grayhill stuff.

 

[HRmeteohub]

Thanx.
These encoders tend to collect fine dust. This amp was used in city that has huge amount of very fine dust from diesel cars. Plus, the owner smokes. Over eight years, the fine particles of smoke glue to the tracks and combine with the moisture from the air, making inter-track gaps conductive (and lubricating oils usually slowly oxidize). At least, that is how they explained it to me. Probably that is why I prefer optical encoders.

Bottom line is, I'll rather open the amp every 8 years rather than buying the new encoder. I guess I am cheap? thrifty?

I have to say, Rotel RA-11 is a fine amp. Not high end, but nice one. It has got a lot of inputs (optical, coaxial, usb, RCA connectors, phono pre-amp, disabling tone controls, etc). Plus, as you can see, they used quality components in all parts of this amp. I have seen many good capacitors, quality op-amp, resistors, and finally good craftsmanship. Not something you see every day. I could not find a service manual, but luckily did not need one for this repair.

My only objection is that the power amp is a bit too simple and perhaps old-fashioned. Perhaps that is the reason that it did not go very well in testing.

Finally (off-topic), don't use this kind of de-soldering wick. It is dry and too stiff. I am going to use this one as a grounding conductor.