Mark IV Problems....popping/crackling and static

[ThatDamnSG]

Recently my Mark IV has started making popping/crackling and static noises right after powering up. After about a minute or so it'll subside but its still worrisome. Last time an amp did this (My Marshall JCM 800) it turned out to be a bad preamp tube. So knowing my tubes were a little old I changed them all out...power tubes and pre amp. Oddly enough, this quieted the problem slightly but its still there. The static noises sound just like if you have scratchy pot and your turning it...only that's not the case. All the pots are clean and it does it when I'm not touching the amp controls. It does regardless if a guitar is plugged in or not, no matter what cabinet its plugged into. I'm at a loss. Any advice, suggestions on what the problem could be.

 

[stephen sawall]

Did you clean your input and speaker jack. How old is it. Maybe the caps are going ?

 

[ThatDamnSG]

Did you clean your input and speaker jack. How old is it. Maybe the caps are going ?

Mr Sawall, you're always the first to answer my questions....thanks!
Yep, cleaned all the jacks, pots, tube sockets. Visually the caps look alright, but I know that doesn't mean anything. Its a 1993 that hasn't seen a lot of heavy use. One thing I have noticed....it doesn't do it in Class A mode at all...completely quiet in Class A. The second I switch out of Class A into Simul Class the noise starts up.

 

[Monsta-Tone]

I just had a similar problem on one of our custom amps. Turned out to be a bad ground connection.
You might look at the Simul-Class A switch (after unplugging the amp and discharging the caps). There should be a wire going to ground from the switch.

I also had the same problem on an old DC-3 that I had several years ago. No matter what I tried, I could not get it to go away. Some of the tube sockets (especially the power tube sockets) were tarnished. I couldn't seem to get them clean enough.

Finally, I replaced all of the tube sockets and the noise magically disappeared.

If it turns out to be something different, please let me know. I'm always interested in what causes things to not work right.

 

[stephen sawall]

Well that's about it without looking at it myself. Even then I have a feeling it would be going to the shop. Good luck with it.

I think I am the only one that hits "View unanswered posts". I hate to see someone take a amp in if they can fix it themselves. ..... And Mr is to formal for me. I am not big on titles and being formal. "Hey you" works just fine with me.

 

[Monsta-Tone]

Where are you located?

 

[ThatDamnSG]

Where are you located?

Me? I'm in Maryland.

 

[Monsta-Tone]

Look on Mesa's website. They have a link to their service centers.

If you can't find one near you, I would be happy to look at it. Lots of guys from the BB send me their amps.

 

[ThatDamnSG]

I turned the Mark IV over to a tech today to have it looked at. I've done everything I'm capable of doing. The scary part is that after I'd cleaned all the pots, tube sockets, and switches the problem actually got worse! Its time to let a pro handle it.

This week I picked up a Studio .22 combo that absolutely smokes! I think its clean tone is better than my Mark IV's. The local shop where I bought it said it had come in used on trade and was pretty neglected when they got it. They gave it to the amp tech they contract all their repairs out to and he went over it, did a new cap job on it, cleaned it up. It sounds killer! So that's who's hands I've trusted the Mark IV to. Have to wait and see what he finds with it.

 

[ThatDamnSG]

Picked the amp up today from the shop that had it...Pro Audio in Beltsville MD. Everyone raved to me about what a great tube amp guru they had there. Got it home, plugged in...SAME problem still happening. Popping/crackling, sounds like frying bacon. They told me they'd found a bad master volume pot and a ground or shielding issue with the V1 preamp tube socket. Two and half weeks of waiting and 85 bucks later its not fixed worth a crap. I am SOOOOOOO pissed off right now. :evil: :x :evil: :x

 

[Monsta-Tone]

That sucks!!!

Is there anybody else to take it to that is near you?

Also, have you tried it in another room, another place, etc.? Maybe the power is dirty or something.

I had this problem in an old DC-3. Couldn't find it for the life of me.
It ended up that I finally got pissed off and replaced all of the tube sockets. The problem went away.

 

[Restless Rocks]

+1 on Monsta's last post. Check the AC wall socket you're plugging it into. If the duplex socket is physically loose it can deffinatly makes pops and crackling sounds come from your amp. Even if socket is good the wire may be loose connecting to it. Also certain high draw appliances in your house can dirty up the AC. Try the amp at a different location to be sure.

 

[Monsta-Tone]

Yeah, I've seen lots of funky wiring issues.
My day job is being an electrical contractor. I get to see lots of stuff!

I'm slowly going through my house and replacing all of the wiring. It originally had 4 glass fuses that were upgraded to 8 breakers in the 70's.
It now has 4 panels and gobs of breakers. Each plug in my music room and workshop is a dedicated 20 amp circuit. I still get pops and clicks occasionally though!


I'm not saying that this is your problem, but it might be a really good idea to take it back to them and try it in their store. Peacefully!
I've had amps go out my door, that came back with the same or different issues. The guy is human, and it's easy to make a mistake. All this being said though, if it makes those noises at his place he **** well better make it right with you!

 

[ThatDamnSG]

I had tried different power outlets, cords, etc. The problem is the caps and a few resistors.

I just got home from taking it to another tech. I'm really kicking myself for not checking the Mesa site first. They were on their listing for authorized repair shops and only 20 mins from my house. I should have just checked there in the first place. Instead I listened to some guys at a guitar shop I usually trust who raved about Pro Audio Services.

Anyway...I took it to Amps And More, the guy diagnosed it as soon as he heard it, bad caps. He opened it up and sure enough some were bumped out on the ends and leaking. He went over everything while I was there and found a few bad resistors as well. He replaced the resistors right in front of me, showed me the problems with a meter and oscilloscope, tightened up the power tube sockets, cleaned all the sockets and pots. The new caps are being ordered directly from Mesa so I'll probably have it back in a week. All for 125 bucks. The other joker had my amp for 2 and half weeks, changed one volume pot which he said was the problem, and charged me 85 dollars. The really screwed up thing is the pot that he changed isn't even brand new....its so obvious it was salvaged off some other piece of equipment. Its old, dirty, and had some funky green plastic housing. I was told "I replaced your master push pull volume with a new high quality US made one" I'm calling my credit card company and Better Business Bureau on their asses first thing Monday. Don't let their so-called "tube amp guru" Drew touch your Mesa, this guy completely screwed me...had my amp for way too long, charged me a stupid amount to basically do a whole lot of nothing. Go to someone listed on Mesa's site.

 

[Monsta-Tone]

Right on! Glad you got it to a good tech!
That does suck about the other guy though. Hopefully you can reverse the charges!

 

[ThatDamnSG]

Yeah, I'm much more at ease now after dealing with this new place. He knows his stuff. He really seemed to love Mesa's too. I don't know what the deal with that first tech is but he was so highly recommended by people I normally trust completely. The guy came off like a total flake in the end. I'm going to have to have a little chat about it with those guys who sent me to him.

 

[stephen sawall]

I can not believe he did not check the caps ? That is one of the first things to check.

 

[ThatDamnSG]

I can not believe he did not check the caps ? That is one of the first things to check.

Yep...I would think that would be "tube amp guru 101" Instead I got a lesson in Complete BS 101.

 

[ThatDamnSG]

After a full month I finally have my Mark IV back After the first fisasco (which I'm still trying to get a refund for) I took the amp to a guy I found on Mesa's site listing for authorized techs. If you're in the Maryland/Baltimore area the place is called Amps And More in Westminster MD. He replaced the caps, a bad resistor, completely cleaned and tightened all tube sockets, pots, and jacks. The amps sounds so much better and isn't popping and frizzling. He really likes Mesa amps especially the Mark series and said he actually really enjoys working them because of how nicely they're built. For some reason, and he didn't seem to want to go into much specific detail, he strongly dislikes dealing with Tremoverbs and Stilettos. If he gets them in he usually ends up sending them back to Mesa for service. I pressed him a little about what he didn't like about them but he wasn't very forthcoming, just shrugged and said "Well...they're not built like that Mark IV, that's a nice amp to have to work on" Good to have the Mark IV back home.

 

[Monsta-Tone]

Right on! Glad to hear it!

I can understand the T-Verb issue a little. I just did a cap job, and replaced some LDR's and some other components that are in a Service Bulletin. I repaired the Reverb too. Did a full tune-up, clean everything and re-tension tube sockets.

The guy gets it back and now the Reverb is acting up again! I ran it for over 6 hours with 0 issues. I'm still scratching my head over it! They are built well, but not like the Marks and DC's and Heartbreakers are.