RM10 mkI: One channel is no longer working

0 Members and 1 Guest are viewing this topic. Read 1631 times.

sdk

  • Jr. Member
  • Posts: 60
RM10 mkI: One channel is no longer working
« on: 21 Jan 2012, 07:08 pm »
The right channel of my RM10 mkI has died.  I'm currently trying to trouble-shoot the problem.  This is what I have done so far:

- Switched R and L channel output tubes.  Resulted in no difference.  Right channel still dead.
- Checked bias of output tubes.  Both sets hold their bias at 30mA.
- Replaced driver tubes.  Made no difference. 
- Checked fuses.  They look OK.
- Opened the amp up.  I didn't notice anything peculair.  I haven't looked under the hood with the amp  powered up yet as I'm not sure what to look for.

Any suggestions before I send the amp to Roger?  I have ordered new output tubes as the current ones are pretty old so we'll see what that does. 

steve f

  • Full Member
  • Posts: 682
Re: RM10 mkI: One channel is no longer working
« Reply #1 on: 21 Jan 2012, 08:32 pm »
Is one channel completely dead, or just not playing?

sdk

  • Jr. Member
  • Posts: 60
Re: RM10 mkI: One channel is no longer working
« Reply #2 on: 21 Jan 2012, 09:36 pm »
It started out at a reduced volume with high distortion in one channel and then it was dead the next time I tried it. 

I also checked the ceramic fuses in a weird sort of way.   The continuity function on my multimeter is broken but I did check the continuity by attaching each fuse to a flashlight bulb and a 9V battery and the bulb lit-up with both fuses.  So they appear OK I guess.

banquo446

Re: RM10 mkI: One channel is no longer working
« Reply #3 on: 25 Jan 2012, 10:09 pm »
Since you have tubes on order already, just have Roger throw in some fuses as well. Even if that's not it, you'll have back ups ready to go. I know when my fuses blew, I wished I had some ready to hand.

mystabg

  • Jr. Member
  • Posts: 23
Re: RM10 mkI: One channel is no longer working
« Reply #4 on: 26 Jan 2012, 06:59 pm »
Have you tried switching the interconects from your pre to the amp to rule out problems upstream of the amp?

sdk

  • Jr. Member
  • Posts: 60
Re: RM10 mkI: One channel is no longer working
« Reply #5 on: 28 Jan 2012, 01:44 am »
Checked both fuses with the continuity checker on my multimeter.  All fuses test out fine.  It's probably a blown resistor.  Sending it back to Roger for repair.