Yamaha stereo amp

hI GUYS, i HAVE A Yammie Stereo Amp which is about 20 years old. Its been relegated to my shed along with a couple of JAMO 8 ohm speakers. The speakers a re very good and in excellent nick. However, every now and then one of them dies. I wasn't sure whether it was the speaker with a loose connection or the amp so I swapped the speakers around. After a while the other speaker died so it was the amp. I took the amp into a bloke who repairs such things and he told me the mode selector pot was di8ckie but they weren't available anymore. That was about 4 years ago. Setting up my new digs (and having left all my really good sound gear in the house I'm giving the ex), I want to try and fix the injured pot. Can someone give me an idea. Is it possible that I can take the pot out of the amp and have a fiddle with it my self oris there some after-market replacement i can fit. I've never taken the lid off. There's 2 things i know about electronics....(1) I don't understand and (2) I still don't understand.....Don't care how fugly it looks.
Thanks

By mode selector, I assume you mean the switch that selects the input (CD/Aux/Tuner/etc). If that is the case then first thing to do probably is to open up the case and take a photo of the switch and post it here. Also, if there are any markings on the switch then they might be useful too. If the switch concerned is not available then a close approximation may be - or there may be another way of achieving the same result. I assume they tried to clean it with contact cleaner or something similar (I have used Inox before with good result)

Peter

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Originally Posted by petersemple

By mode selector, I assume you mean the switch that selects the input (CD/Aux/Tuner/etc). If that is the case then first thing to do probably is to open up the case and take a photo of the switch and post it here. Also, if there are any markings on the switch then they might be useful too. If the switch concerned is not available then a close approximation may be - or there may be another way of achieving the same result. I assume they tried to clean it with contact cleaner or something similar (I have used Inox before with good result)

Peter

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That was quick. Thanks Peter. I have some RP7, is that the same as Inox?
I'll take a pic of the pot (yes, as you rightly assume, its the input selector) and have a squiz for some numbers. I'll be going up to the new digs next Monday so will hopefully get a pic then.
Cheers
and thanks again.
Mike

Odd, if its a regular type selector switch it'll be easily (finicky but easy) to replace. Strange the repair bloke wouldn't just use a stock Jaycar/Altronics/Dick Smith etc part. Unless it's relays or something.

The switch may be fine, just a dodgy solder joint. A little new solder on each connection may do the trick.

If you don't switch sources then you can just bypass the selector to the volume pot.

If it's a dickie wire connection on an input pin then hook your CD player/tuner/whatever to another input on the back of the amp (CD, tuner or aux will work), flip the switch to that input and see if it still buggers up.

It's all moot without seeing it :)

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Originally Posted by Shedhand

That was quick. Thanks Peter. I have some RP7, is that the same as Inox?
I'll take a pic of the pot (yes, as you rightly assume, its the input selector) and have a squiz for some numbers. I'll be going up to the new digs next Monday so will hopefully get a pic then.
Cheers
and thanks again.
Mike

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ARRRRRGH:oo:..... not RP7, WD40, or Inox or amything similar.

What you need is an electronic contact cleaner and lubricant.

The othr stuff may seem to do something, but the long term effects are not good and they don't help as much as a proper contact cleaner.

you can also get contact cleaners without the lubricant, but you realy don't want that either, because it will wash out all the grease or oil or whatever and leave nothing behind.

But I assume ( hmm) that the tech you took it to tried that.

one the subject of dry joints arround the switch or fractured PCB tracks arround the switch, that would be a very likly thing to look for.

But you need good eyes, a steady hand and a decent soldering iron.

As for replacing with a generic swith from jaycar......it is most likly that the switch is a custom and PCB mounted.
In fact you may have bucklies of getting into it to clean it....lots of the newer stuff is completely sealed to allow for modern manufacturing processes.

Anyway, open it up and lets see a pic.

cheers

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Originally Posted by soundman

ARRRRRGH:oo:..... not RP7, WD40, or Inox or amything similar.

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Yeah dont do it
RP& and WD40 will shag it forever

I would (and do) use this
http://www.crcind.com.au/catalogue.n...r?openDocument

I didn't know that you're also an electronic wiz Nev, you must truly be a man of many talents.

First mistake: You did not list the model number.
Second mistake (potential): Squirt the switch with something, some guy you've never met, has suggested.

I'm a guy you've never met. I also happen to be an audio repair professional with 40 years experience. Some of the old Yamaha mode switches are bad news. They sometimes respond to cleaning. Sometimes, not. Whatever you do, use the best quality cleaning stuff you can get your hands on. I use Electrolube™ for such items.

It's a motorised switch, right? They were the most troublesome.

Ow, the guy who suggested Inox to me as a contact cleaner isn't a repairer, but is an audio engineer who has been responsible for maintenance and minor repair of a fair bit of expensive gear. I hate to think what destruction he may have left in his wake if it's as bad as that. Glad there are knowledgable people on here.

Peter

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Originally Posted by Zaphod

First mistake: You did not list the model number.
Second mistake (potential): Squirt the switch with something, some guy you've never met, has suggested.

I'm a guy you've never met. I also happen to be an audio repair professional with 40 years experience. Some of the old Yamaha mode switches are bad news. They sometimes respond to cleaning. Sometimes, not. Whatever you do, use the best quality cleaning stuff you can get your hands on. I use Electrolube™ for such items.

It's a motorised switch, right? They were the most troublesome.

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My memory fails me at times like this. I'm going over to the new digs in the next couiple days and will get the model number and the numbers of the switch. Is Electrolube available at an electrical trade shop?

No not motorised. Its the manual input selector (i.e. CD/tuner/Tape/DAT/Accessories or whatever labels they use.

The amp is one I bought about 1996/7.

Anyway thanks for the helpful comments as I know less than nothing about the guts of these things. I'll be back with info and photos for the boffins to looks at.
Cheers
Mike

The best contact cleaners I have found are made by Caig Laboratories in th U.S.
This is an oil based lubricant that won't leave the controls and switches feeling like they had a handful of sand thrown in like silicon based cleaner does to a lot of pots.
http://store.caig.com/s.nl/sc.2/category.188/.f

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Originally Posted by Shedhand

I took the amp into a bloke who repairs such things and he told me the mode selector pot was di8ckie but they weren't available anymore. That was about 4 years ago.

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Originally Posted by Shedhand

No not motorised. Its the manual input selector (i.e. CD/tuner/Tape/DAT/Accessories or whatever labels they use.

The amp is one I bought about 1996/7.

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Hi Mike

Are you sure you and the techy are referring to the same switch?

I have a Yamaha CR1000 amp, 1979 vintage, and the five gang mode selector switch selects the mode of output to the speakers - mono, stereo or reverse stereo. When I had problems about the same time as you the techy said he might be able to get a replacement switch ($$$$s), could replace it with toggle switches or bypass it altogether - did I ever want to switch between mono or reverse stereo? In the end he found a dry connection and the old switch is still in use.

Cheers

Graeme

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Originally Posted by GraemeCook

Hi Mike

Are you sure you and the techy are referring to the same switch?

I have a Yamaha CR1000 amp, 1979 vintage, and the five gang mode selector switch selects the mode of output to the speakers - mono, stereo or reverse stereo. When I had problems about the same time as you the techy said he might be able to get a replacement switch ($$$), could replace it with toggle switches or bypass it altogether - did I ever want to switch between mono or reverse stereo? In the end he found a dry connection and the old switch is still in use.

Cheers

Graeme

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G'day Graeme. I finally unpacked the Amp on the weekend. I'll take some pics, track down the part number and post some more info about it.
Cheers
Mike

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Originally Posted by petersemple

Ow, the guy who suggested Inox to me as a contact cleaner isn't a repairer, but is an audio engineer who has been responsible for maintenance and minor repair of a fair bit of expensive gear.

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Don't worry, Inox is nothing like RP7 or WD40. It is absolutely fine to use on electronic gear. Unlike the others it was unfairly grouped with above Inox has no silicon or kero solvents and is anti-static. It's also completely inert i.e., non-conductive so make sure you're using it in the correct context.

Having said that the Caig Labs stuff is very good for faders and such.

A good cleaner and cheap is methylated spirits.Make sure to dry it completely before adding power ,wait 24 hours .It will clean greasy muck with the aid of a cotton bud.If the problem is corroded metals then inox is the better choice.I use a hairdryer to speed things up.I have also used $2 degreaser on tv boards but you have to do a second clean to remove the degreaser slick.I hose the board off with cold water and the hairdryer will dry it in minutes.These are cheap remedies but for critical equipment use the proper trade solvents.