Yamaha M-35 troubles

nguyendot

So I have a pair of M-35 stereo amps that I love. They're low powered and I plan on using them to bi-amp a pair of speakers someday. The problem is one of them has no/scratchy output on the left channel. It cuts in and out by itself and sounds scratchy when it happens.

I really want to have it repaired. What should i look for inside if I can maybe fix it myself? If not, where can I take it that wont cost an arm and a leg?

AudioGenics

just checking to see if your did the channel swap L-R and R-L
to confirm it is the amp and not in the speakers or source.

Systems

The cutting in and out might indicate a wonky relay.

nguyendot

I did swap, it is definitely the amp. If i switch it into 4 channel mode, only the pair on that side work as well.

What can I do about a wonky relay?

Systems

nguyendot wrote: »

What can I do about a wonky relay?

Keep in mind that is only one possibility,it could be somthing else entirely.If it is the relay it would need to be replaced, but you could try resoldering the pins to the PC board as it might be just a cold solder joint.

nguyendot

I will definitely look into that. I may look at the solder points on this amp and see if i can fix it. Can a bad or rusty pot cause this too? It has 2 volume controls and if i mess with that channels volume controls I can sometimes get it to come back, but only at full volume.

Systems

nguyendot wrote: »

Can a bad or rusty pot cause this too? It has 2 volume controls and if i mess with that channels volume controls I can sometimes get it to come back, but only at full volume.

Yes if thats the case then I would take a closer look at that pot.Try bypassing it and see what happens.

nguyendot

excuse my ignorance, how do i do that?

Systems

nguyendot wrote: »

excuse my ignorance, how do i do that?

Desolder the signal input and output pins of the pot or (remove entirely) and replace with a wire jumper.If you can post a pic of the pot and how it is mounted I might be able to give you further guidance.

nguyendot

Will do when I get time this weekend. Headed out of town right after work today. But I definitely want to get this fixed. I love having a matched pair of amps.

I understand exactly how this troubleshooting (logically) works, but not how to go about it.

Let you know as soon as i can.

shadowofnight

nguyendot wrote: »

Can a bad or rusty pot cause this too? It has 2 volume controls and if i mess with that channels volume controls I can sometimes get it to come back, but only at full volume.

It's the volume control pot....same exact problem with the one I had . Since the amp only had spring type speaker connections in the rear, I gave it away to a friend.....he fixed it by replacing the pot.

AudioGenics

just another thought

did you try the special spray cleaning and lubricating the volume pot

I forgot what another post suggest DeTox Gold
I'll search for the name.

AudioGenics

plain DeOxit and DeOxit Gold.

The first cleans the second conditions the contacts.

nguyendot

Where can I get it from?

Also, why is his power LED blue/white? I'd love to change mine to that color.

Also, if I were ambitious, could i change out the speaker connectors for 5 ways?

AudioGenics

I have not used this product but similiar cleaner/lubricant product

here is the url that I found regarding DeOxit $9.99

http://www.radioshack.com/product/index.jsp?productId=2104746

AudioGenics

appears to be out of stock online
check local stores...

nguyendot

THanks, will try that when i get home saturday

nguyendot

I tried deoxit and it did nothing, the channel is still dead. It doesn't even scratch anymore, it just doesnt have any output whatsoever. I have no idea what to do, i'm not that into the circuits and stuff.