Author Topic: Mesa Boogie Walkabout problem. (Read 419 times)

jazzyvee · « **on:** February 10, 2013, 12:52:33 PM »

I have just encountered a problem with my mesa boogie head.
I did a gig with it on Friday and it was fine no problems. Today i was just starting my practice session and initially the playing volume was fine, then all of a sudden it dropped to about 50% volume, started crackling and giving a distorted sound then a few seconds later it was back up to normal sound.

At first I thought there was a problem with my DS-5 again, so I took out the plug and used a standard jack and the sound was just the same. Just to be sure I tried a different bass which I know has fresh batteries and the same thing happened after a few seconds of playing. So I'm pretty sure it's something to do with the amp.

I've never had a problem with it before and it's the amp i use on most gigs.

Any ideas?

Jazzyvee

edwin · « **Reply #1 on:** February 10, 2013, 01:27:14 PM »

Are there tubes? If so, check those. Also, if there are send/return loop jacks, exercise those. They can have switches which get dirty and cause the symptoms you describe.

tncaveman · « **Reply #2 on:** February 10, 2013, 05:46:38 PM »

I've had that happen on numerous amps/guitars/basses and it always seems to be a plug/jack issue or a pot that needs to be exercised. The contact cleaners help too.

Stephen

pace · « **Reply #3 on:** February 10, 2013, 06:32:40 PM »

Cables?!? Are any of your patches of the solderless George L / Lava variety?

If you've deduced that it is occurring within the Mesa, then check the board for any cracked solder joints, especially if the jacks are surface mount. Also check the filter caps' connection to the board, sometimes the solder joints crack, if so, after resoldering, you can use a glue gun to reinforce the caps on the board.

alembic76407 · « **Reply #4 on:** February 11, 2013, 01:09:43 PM »

Preamp tubes would be my guess
same thing is going on with my Boogie 400+

David T

xlrogue6 · « **Reply #5 on:** February 12, 2013, 09:29:49 AM »

If you've got one of the earlier Walkabouts (2 inputs instead of one with a switch) it may be your FX loop, which lacked a bypass switch in that era. If yours is of that era, try jumpering the loop jacks with a short cable. If that's not it, there have been a couple of circuit updates to the Walkabout that apply to serial numbers under 2001.

jacko · « **Reply #6 on:** February 13, 2013, 05:32:07 AM »

I had an identical problem years ago on a trace elliot. Turned out to be dry joints on the PCB. Thumping the top of the amp hard would usually 'fix' it for a short while.

Graeme

jazzyvee · « **Reply #7 on:** February 13, 2013, 11:48:40 AM »

Strangely enough as I've been playing it this week it hasn't repeated the effect it had on Sunday so it's probably gonna be one of those dreaded intermittent problems. I'm gonna try the Jumper cable and if that doesn't solve it I will take the back off and check the joints etc.

Jazzyvee

keith_h · « **Reply #8 on:** February 13, 2013, 07:11:56 PM »

J-V, Most of the heads and preamps that have any type of effects or insert loops use switches on the 1/4 jacks. These will oxidize over time when not exercised and cause distortion. I suggest you get some Caig's DeOxit and spray the connectors and then exercise them by inserting a plug in and out a few times. If you wish to be more thorough open the unit up and use the DeOxit and a business card to burnish the contacts, if they are not enclosed in a housing. A relay contact burnisher would be better but this is not something most folks would have lying around.

Keith

jazzyvee · « **Reply #9 on:** February 15, 2013, 03:40:54 AM »

I tried the jumper cable between send and return jacks and the volume and quality of the sound jumped up incredibly so it must have been deteriorating for a while. In actual fact I had wondered a while ago if I had blown one of the the speakers or tweeter because of the intermittent scratchy sound but now I doubt that is the case.
This weekend I'm gonna spend some time checking my gear out as I have a couple of important showcase gigs for festival promoters comming up next month. Maybe i will get time to take the back off and have a clean up inside.
Jazzyvee

rustyg61 · « **Reply #10 on:** February 15, 2013, 07:33:34 AM »

That must be an inherrant problem with Mesa, our guitar player has a small Mesa Boogie amp that has cut out on him on several gigs & after that last time he said he jupered the effects loop & it went away too.

jacko · « **Reply #11 on:** February 15, 2013, 07:44:32 AM »

What if you want to use the effects loop?

graeme

rustyg61 · « **Reply #12 on:** February 15, 2013, 07:47:52 AM »

I don't know, our guitar player just bought a new amp while he's trying to figure out the Boogie problem.

keith_h · « **Reply #13 on:** February 15, 2013, 09:47:46 AM »

When you jumper the effects loop you bypass the bypass switches built into the connector. These switches allow the signal to pass through when you aren't using the jacks. The fact that the jumper resolves it indicates to me that oxidation on the contacts is what is causing the problem. I run into the same thing on my Navigator. Since the connectors never get used they don't open and close to keep the contacts clean. A little DeOxit on the contacts and exercising to allow the contacts to wipe and I'm good to go for another couple of years.

Note: I am not an endorser for DeOxit but it is easy to find at your local Radio Shack and works well.

Keith

cozmik_cowboy · « **Reply #14 on:** February 15, 2013, 07:20:55 PM »

I'm jealous, Keith; went looking a couple days ago, and my local Cell-Phone-Plan Shack had never heard of it (got a can of CRC QD Eletronic Cleaner at the hardware - anyone know anything I should know before I spray in any pots?)
Sorry for the highjack; glad the problem's figured)

Peter