What the...? (Tube Sockets)

[Leng]

I've had my '92 DR for over a year now, just went to change powertubes for the first time today and found this:

I have no idea what it is or how to clean it. Do you think it's oxidation or the previous owner's Dr. Pepper?

I'm trying to clean my DR using Elpelotero's guide, but he asks for duct tape to be put over all the holes... and as you can see in the mirror reflection, there's a little crap going down into the hole.

Thank you guys so much for any advice you may have!

 

[Leng]

My dad says it's oxidation, and to leave it alone.

Still curious to see if anyone agrees.

 

[Elpelotero]

Never seen stuff that bad...I'd try either denatured alcohol or wiping DE-OXIT on it with a Qtip. It may be worth calling Mesa today before they close shop Friday.

 

[nwoforlif]

These sockets are made from ceramic material. At least it looks that way on my DR and they are ceramic on my probe testers. It looks like electrical arcing burns to me, mixed with a very little dried up liquid (the cause of the arcing). Ceramic sockets do not oxidize or rot. Why do you think tiles are made out of them and dishes (because it does not corrode).

NWOFORLIF

My dad says it's oxidation, and to leave it alone.

Still curious to see if anyone agrees.

 

[Leng]

<Repeat post>

 

[Leng]

Thanks a ton, guys.

Mesa wasn't sure how to clean it, so I'm very open to advice right now. They said they might call me back.

I'll try denatured alcohol while I wait.

 

[tetsubin]

Replacing them would probably take a tech 10 minutes. That's what I vote for.

 

[Leng]

Tetsubin: I just got an estimate @ 90 - 160 minutes to replace the 4 power tube sockets.

Do you really think I should, considering there's none of this material (oxidation or otherwise) anywhere in any of the pin holes? They all look clean in the pin holes, just that weird stuff on the top and in the center hole on 1. The amp works beautifully.

The denatured alcohol might work - I don't have time to test it further before work. Will probably take a long time. Any other advice, especially if anyone's ever cleaned these would be MOST appreciated.

Anything other than q-tips anyone can think of? I'm worried about cotton particles getting in the pin holes.

Thanks guys.

 

[Elpelotero]

toothbrush? toothpick with something wrapped around?

 

[tetsubin]

90 minutes? Perhaps I'm wrong, but aren't the power tube sockets of the DR chassis-mounted? I think that's true for every Mesa amp. (See a pic of a DC-5 in this thread: http://forum.grailtone.com/viewtopic.php?t=29448)
If they are then I'd make a rough guess:
1. unscrewing 4 power tube sockets = 2 minutes; if you're experienced in screwing = 1 minute; if you're experienced in screwing up = 10 minutes
2. desoldering the connections to them = 8 mins
3. putting new tube sockets in = see 1.
4. soldering the connections to them = 15 mins

So 10 minutes was too low, I didn't think of 4 sockets, just 2. But 30 minutes, 40 max., should do it.

Changing the sockets is the "cleanest" solution. Of course, just getting rid of the junk might work just as well - but I like to keep my amps in the best possible shape. The tech could also have a look at the circuit board to see if it's damaged.

 

[6L6C]

Since you are putting new tubes in there anyway go to Radio Shack or some electronic store and pick up a can of “Contact cleaner”, and try cleaning those sockets with that . I think it will be a little more aggressive than denatured alcohol. If that works out good while putting in your new tubes take a tube it can be one of the old ones, spray the pins and run the sockets a few times repeat on all sockets, might be some crap in there also, and it’s just good practice when replacing tubes.

When trying to clean those sockets don’t spray the contact cleaner on them. Just spray into a Q-tip or paper towel and work it that way.

 

[Leng]

Thanks, guys... all much appreciated. I'll get some contact cleaner also, the denatured alcohol is kinda weak.

And tetsubin, I agree... My local mesa repair is freaking ridiculous how pricey the estimates they've given me on anything like this I want done to my amp. I wish I lived somewhere with an experienced tech. :roll:

 

[212Mavguy]

Definitely not necessary to replace the sockets, just clean them. A proxibrush with contact cleaner in the bristles works great to clean out the contact holes. Use eye protection and work with contact cleaner outside or in a very well ventilated area. Wear rubber gloves. I use Jiffy Bath contact cleaner. Good idea to put a wad of kleenex on back side of socket to catch any drippings if there is room to do so. Craig Deoxit is also excellent. There are less poisonous and flammable contact cleaners out there, but I am not familiar with the brand(s). Some leave a lubricant behind, that is not a bad thing.

 

[Leng]

Thanks Mavguy and 6L6C!

A proxabrush is exactly what I was looking for. Hopefully I can find Jiffy Bath, if not, RS does have contact cleaner.

 

[Don]

Don't replace the sockets.

Any good contact cleaner will be fine.

Don't use a cleaner with lubricant in it!

 

[Leng]

Some leave a lubricant behind, that is not a bad thing.

Don't use a cleaner with lubricant in it!

Anyone care to elaborate? I'm very curious, 'cause I don't want to hurt my baby. :!:

Does this mean I shouldn't use the Jiffy Bath?

EDIT: Got her clean and pretty again, using RadioShack Precision Electronics Cleaner. They had contact cleaner with lubricant, decided to play it safe and get this stuff because it evaporates completely and Don said not to use lube...

 

[212Mavguy]

Have had zero problems after cleaning sockets with a cleaner (Jiffy Bath) that had a lube residue. Depends on how electrically conductive that residue is. I did try my best to remove excess after doing the job. Was a point to point turret board chassis. Recently cleaned 13 pots on a buddy's Hughes & Kettner Attax 120, circuit board design, he is a luthier, used Craig Deoxit and he claimed the lube residue was non conductive. The amp worked great, and after subbing a GE longplate 12ax7 for an old Sovtek in the preamp he was floored at the tonal improvement.

 

[trey85stang]

couple days old... I just picked up a mark 3 a few weeks ago and mine has the same thing. My first thought was to replace the sockets.. and I was going to do that until I pulled the chassis and noticed everything was fine on the inside and the pins were sturdy nothing looked burnt on the inside.

I saw no reason the replace them. It was probably a tube that blew and arced that caused that. As for the middle hole.. there is noth electronic there anyways so no need to worry or clean it imo as once you put the tube in you will never know its there.

 

[Leng]

Aye, trey - I'm sure I'd be fine if I didn't clean any of it, 'cause the burns were only on the one big hole and on the outer surfaces of the sockets - not in the pinholes themselves where the tubes slide. Just did it 'cause I love her.

Funny you said that, 'cause I actually did clean everything but the burns in that hole. It'd be hard to clean without getting little bits of whatever into the chassis. I'm not going to clean everything possible, I like the grungy look of the plate metal in contrast to the surgical-white sockets rising with clean, sharp looking tubes projecting from them. Everything else just needs to be dusted now and again. :wink: