Yamaha R-50

[audiotemp]

I have seen this STK listed for sale. Is there a specific source I should use or are they all pretty much the same?

Almost all the STKs available online are "fake". The original maker stopped making them long ago. Some are reported by people here (and elsewhere) to work OK but some are just junk.

An original part, if you can find one, will likely be $50+ but it is also possible to pay that much and still get a fake. It's just a gamble.

 

[Hamm]

Is this what your speaker connections look like? (This is from thr R-50 user manual.)

Do you see where it says speakers should be 8 to 16 Ohms?

Who told you the R-50 could drive 4 Ohm speakers?

You didn't include a pic. While researching the R-50 I read, somewhere, that it was good for low impedance loads. I have no idea where I saw that. I'll look at the back of my unit tomorrow. I have used it with those Control 1s for years.

PS: I just googled up an R 50 owners manual and it says speakers anywhere from 4 to 16 ohms for one pair.

PPS: I just looked up Control 1 speaks on the JBL site and it says they are 8 ohms. Panic averted.

 

[Hamm]

Almost all the STKs available online are "fake". The original maker stopped making them long ago. Some are reported by people here (and elsewhere) to work OK but some are just junk.

An original part, if you can find one, will likely be $50+ but it is also possible to pay that much and still get a fake. It's just a gamble.

How would I go about finding a real one? EBAY?
PS: I see them on EBAY, marked as: "New Original SANYO". Are they lying?

 

[mbz]

I see them on EBAY, marked as: "New Original SANYO". Are they lying?

Are they shipping from China?
Not that a good indication, some people buy hundreds from China for a dollar each and onsell from US or EU for a nice margin.
Best to find a AK thread with a satisfied ebay STK purchase. Do your homework. Look for a parts unit? Or get something better, plenty of options.

 

[Hamm]

Are they shipping from China?

First one on the list ships from New Jersey. It's $12.45. Seller has a 99.7% positive review.
Seems like it's worth taking a chance on. I should have those replacement capacitors by maybe tomorrow.

 

[audiotemp]

I have used it with those Control 1s for years.

PS: I just googled up an R 50 owners manual and it says speakers anywhere from 4 to 16 ohms for one pair.

PPS: I just looked up Control 1 speaks on the JBL site and it says they are 8 ohms. Panic averted.

Well, you're right about the OM:

I find that JBL's website says the Control 1 is 4 Ohms but apparently you have something that says 8 Ohms? You have an older version, maybe?

It all falls into the category of mysteries of the universe, I guess.

 

[audiotemp]

You need to do some checking of external components before replacing the STK. You presumably have 75 volts across R333+R335 which means one or both are getting pretty hot and/or have changed value. C257 is probably being subjected to reverse polarity voltage, as is C243. R337 probably was heated momentarily before the protection kicked in.

 

[Hamm]

I find that JBL's website says the Control 1 is 4 Ohms but apparently you have something that says 8 Ohms? You have an older version, maybe?

Now I see that there are two versions of the Control 1s. One is called "pro" and IS listed as 4 ohms. Not sure which I have. I'll look into it.

 

[Hamm]

You need to do some checking of external components before replacing the STK. You presumably have 75 volts across R333+R335 which means one or both are getting pretty hot and/or have changed value. C257 is probably being subjected to reverse polarity voltage, as is C243. R337 probably was heated momentarily before the protection kicked in.

Will do cap'n. To the best of my meager ability, that is...

 

[Hamm]

I'm getting ready to make an Amazon order. Is there any kind of reasonably-priced testing device I should have beyond just my little primitive multi-meter?

 

[Hamm]

I have discovered that my old Radio Shack multimeter is not able to test capacitors. I guess I'm going to order a new one. Any suggestions?

 

[Hamm]

I have been tied up with other projects, and have not quite finished choosing what new multimeter to order. Sooo many choices! I do have one question for now. I did receive my new capacitors. The old ones seem to be still very tightly clued to the board. The glue looks brownish. Is there any solvent I might try to loosen that glue that won't damage the board?

 

[avionic]

The glue looks brownish. Is there any solvent I might try to loosen that glue that won't damage the board?

I just unsolder the old cap. Then wiggle the old cap back and forth. The glue will break away in big chunks.. But, that's me.. To answer your question. Acetone will break down the glue residue. Just keep the acetone away from styrene/styrol film caps. Acetone dissolves polystyrene on contact.

 

[Hamm]

I just unsolder the old cap. Then wiggle the old cap back and forth. The glue will break away in big chunks.. But, that's me.. To answer your question. Acetone will break down the glue residue. Just keep the acetone away from styrene/styrol film caps. Acetone dissolves polystyrene on contact.

Will try that. What adhesive should I use, if any, when installing the new caps?

 

[avionic]

Will try that. What adhesive should I use, if any, when installing the new caps?

Not required for most caps .. The only adhesive I use is for holding heatsinks in place. If they are not screwed down.

Permatex Ultra Black...

 

[Hamm]

Alright... finally back to this project. I got my new meter. It's sort of a mid-range one - EXTECH EX330 - around $55 on Amazon. I should have those new caps installed by tonight and then will review the recommendations for what to test.

 

[Hamm]

Change of plans. I have to travel for my work for a couple of weeks. I'll have to get my tuner working sometime later. Sigh...