The Boogie Board

Discussion Forum for Mesa Boogie Products
It is currently Tue Jun 27, 2017 12:20 am

All times are UTC - 6 hours [ DST ]




Post new topic Reply to topic  [ 5 posts ] 
Author Message
PostPosted: Mon Sep 28, 2015 5:26 am 
Offline
Mark I

Joined: Fri Mar 20, 2009 7:50 pm
Posts: 25
Location: Melbourne Australia
Hi All

A while ago I noticed that the foot switch would stop switching between channels or only go between clean and red modes. When I jiggle the cable the channels will switch back and forth, and then it will work for a while. In trying to work out what the issue was, I started to use the rear FSW jack. This worked fine for a while but at rehearsal last weekend, it started doing the same thing. I removed the foot switch cable from the amp and tried changing the channels manually and things went from bad to worse ...

All of a sudden, stuck on red mode - no sound was coming from the amp.
The Clean and Blue modes were still working fine (manual switching)

I then switched the attenuator off and all of a sudden the red channel works again. I tried this a few times with the same result. So, it is now

Attenuator on = no red channel
Attenuator off = all channels work - but bloody loud ;-)
Still no foot switching

So, I think I now have two problems and am not sure how to attack them.

For the foot switch issue, I wondered if the cable could be part of the issue so I will get another stereo cable and try it out
For the "no red channel" in Attenuator mode, I have no idea where to even start.

Has anyone seen this before
Any ideas of what to look at ?

I think it might be tome for a warrantee repair job ...

Any suggestions appreciated, thanks.

_________________
[size=85]

Mess Boogie RA-100
2 x 1936 Cab
Mesa Boogie Express 5:25
MM Like II
MM Luke III
'78 Fender Stratocaster
Pedals, Pedals, Pedals ...


Top
 Profile  
 
PostPosted: Mon Sep 28, 2015 11:59 am 
Offline
Donating Member
User avatar

Joined: Thu Oct 15, 2009 1:30 pm
Posts: 2530
Location: San Francisco Bay Area, CA
Haven't heard of this, but one thing you might look for is that the attenuator makes it a lot hotter in the chassis. When the attenuator is on, the extra heat may make an intermittent connection totally open or shorted due to the metal expanding.

_________________
Electra Dyne Head
JP-2C WICKER, Baby!
Mini Rectifier blue LED
Recto 2x12 Horizontal
2x Recto 2x12 Vertical


Top
 Profile  
 
PostPosted: Mon Sep 28, 2015 3:37 pm 
Offline
Mark I

Joined: Fri Mar 20, 2009 7:50 pm
Posts: 25
Location: Melbourne Australia
elvis wrote:
Haven't heard of this, but one thing you might look for is that the attenuator makes it a lot hotter in the chassis. When the attenuator is on, the extra heat may make an intermittent connection totally open or shorted due to the metal expanding.



Hi Elvis - thanks for the info. I do run the multi-soak all of the time. I also run the fan on hi just to be sure. In Melbourne Australia - it is early spring so temperatures are pretty mild. Sunday arvo when it happened it was a nice 21 degrees so I suspect this is not the culprit. I will however run it up next weekend when I am back from a business trip.

cheers.

_________________
[size=85]

Mess Boogie RA-100
2 x 1936 Cab
Mesa Boogie Express 5:25
MM Like II
MM Luke III
'78 Fender Stratocaster
Pedals, Pedals, Pedals ...


Top
 Profile  
 
PostPosted: Tue Oct 13, 2015 6:35 pm 
Offline
Dual Recto

Joined: Fri Feb 22, 2013 7:31 am
Posts: 2101
Location: North Carolina
If there is nothing wrong with the cable, there may be a loose connection somewhere in the amp. I believe this one also has the ribbon cables like all of the other packed amps. You could reseat the ribbon cable that connects to the PCB. Use caution as there may still be high voltages stored in the power supply capacitors. It has been a while since I removed the RA100 Chassis from the shell. Tubes are so easy to access there has not been any need to do this.

_________________
TC-50 HD
JP-2C HD
MARK V C
ROADSTER HD
RA100 HD
RA100 C


Top
 Profile  
 
PostPosted: Mon Oct 26, 2015 2:59 am 
Offline
Mark I

Joined: Fri Mar 20, 2009 7:50 pm
Posts: 25
Location: Melbourne Australia
Thanks for your replies. The amp has been off at the authorised repairer for a few weeks now. Haven't heard anything back yet so I guess it wasn't straight forward. I will let you all know what it turned out being - just in case others on the forum have similar issues.

_________________
[size=85]

Mess Boogie RA-100
2 x 1936 Cab
Mesa Boogie Express 5:25
MM Like II
MM Luke III
'78 Fender Stratocaster
Pedals, Pedals, Pedals ...


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC - 6 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group