Need help with VC508

[vladamiraaron]

My VC508's power transformer is kicking the bucket. Do any of you folks know where I could pick up a replacement without sending the thing in to SLM or a LMS (The 2 local music shops near me wanted nearly as much as the amp was new in labor and then adding parts on top of that)?

It's a plug and play 5 minute kinda replacement and I'm not gonna pay any amp tech to remove two screws, unplug the transformer and then plug and screw the new one in for that kind of cash. Thankyou for any suggestions or insight!

[sumgai]

vlad,

Hi, and welcome to the NutzHouse! ;D

First, I'd be suspicious of anything that could be plugged and played, particularly if it were a heavy part like a transformer (should be).

Second, if it truly is nothing more than a socket interface, then have you removed it, cleaned the pins (both sides) and then tried the unit again?

Third, how do you know it's the transformer itself, and not some other component? IOW, who did the troubleshooting here.......?

Fourth, this is the dirty little secret of today's world (and has been for the last couple of decades) - the cost of an assembled unit is far, far below the cost of the individual parts, purchased one-by-one. Coupled with labor costs, that makes any repair job subject to anaysis of the price/benefit ratio. Which in turn gives rise to this, our modern "throw away" society. Somewhere along the line, we took a turn for the worse, IMHO.

Chances are excellent that if SLM won't send you a transformer (at a decent price), then you're gonna be installing a substitute unit. And most likely with a soldering iron. How's your eye-to-hand coordination these days?

HTH



sumgai


p.s. Bear in mind that I am taking your word for it about how the transformer is constructed and mounted, I've yet to have one of these come into the shop. There may be more here than meets the eye, that's all I'm saying.

[vladamiraaron]

sumgai said:

vlad,

Hi, and welcome to the NutzHouse! ;D

First, I'd be suspicious of anything that could be plugged and played, particularly if it were a heavy part like a transformer (should be).

Second, if it truly is nothing more than a socket interface, then have you removed it, cleaned the pins (both sides) and then tried the unit again?

Third, how do you know it's the transformer itself, and not some other component? IOW, who did the troubleshooting here.......?

Fourth, this is the dirty little secret of today's world (and has been for the last couple of decades) - the cost of an assembled unit is far, far below the cost of the individual parts, purchased one-by-one. Coupled with labor costs, that makes any repair job subject to anaysis of the price/benefit ratio. Which in turn gives rise to this, our modern "throw away" society. Somewhere along the line, we took a turn for the worse, IMHO.

Chances are excellent that if SLM won't send you a transformer (at a decent price), then you're gonna be installing a substitute unit. And most likely with a soldering iron. How's your eye-to-hand coordination these days?

HTH



sumgai


p.s. Bear in mind that I am taking your word for it about how the transformer is constructed and mounted, I've yet to have one of these come into the shop. There may be more here than meets the eye, that's all I'm saying.

I've taken it to both of my local music shops to have it looked at and estimates on repair given. The diagnosis was the same both times. Both have their own "world renown" tube amp guru repair tech. I do think they probably know what they are talking about but as with all areas that I am not an expert, I have to go with the expert opinion. Who knows, perhaps I've got two wrong diagnosis? I was little leary of the first one when one of techs remarked that he first figured it out by smacking the transformer with a small mallet whenever the amp went haywire and it would begin functioning properly. I then took it in for a second opinion. I didn't mention the first diagnosis and simply told the second shop that I didn't know what was wrong with it but it wasn't functioning properly and described the symptoms.

The Transformer is attatched to the chasis via two screws and it terminates into its own female multi-pin plug...which then plugs into the board ;D. I'm pretty adept at soldering if it comes down to it but it would be nice to not solder on the board if I don't have to.

It really is plug and play as it stnds right now though.

Thanks for talking about it with me.

[sumgai]

vlad,

OK, so it's a Molex connector of some sort, that's a start. And if other, allegedly trained, individuals came up with the diagnosis, then so be it. Although I gotta tell ya, whenever I perform percussive maintenance, it's almost always an indicator of a bad solder joint, or in the rare instance, a bad cap. It's not necessarily true that the problem is physically located exactly where the percussion took place, lots of looking around will likely be the case. (Sometimes when I suspect a bad solder joint somewhere, and I can't see anything wrong, I'll just shotgun the whole thing - re-heat every last ever-loving joint. That usually fixes it! )

Transformers are not in the habit of burning a wire in the middle of the winding, and then letting that broken point pass current for awhile, then not passing it at other times. Usually, a burnt spot will smell, well, burned-like, and that smell will last for a long time, like months, or longer. If you've been reading some of the past postings here, you've probably noted that ChrisK's favorite saying is "Clues are".

Also, the wiring at the connector itself (the crimped pins within the housing) may be bad - I'd vote for that almost as soon as a bad solder joint.

Bottom line - you've likely done this, you sound pretty thorough, but I suggest that you look around the innerweb, and see if anyone else has had a similar problem. Is there a history of these things having transformer problems? If you can't find anything, then yeah, it'd be time to discuss it with one or both of those technicians. If they haven't picked up a soldering iron by the business end for quite some time, then they should know that either a large batch of transformers were all bad (which would be common knowledge by now), or else the first guy's conclusions were derived too quickly. Of all the components in a circuit, a transformer has just about the least likely chance of going bad without being forced to do so, and in my experience, the reasons for such are always plainly detectable from the outside.

Keep in mind that I may also come to the same conclusion, if I were to see this particular unit, there's just no way to be sure of a long-distance diagnosis like this. However, the neat thing here is, there's a plug/socket for this thing - how handy is that? Simply disconnect the suspect part, and jury-rig an acceptable substitute into that connector. Play until you are satisified that either the rest of the amp is OK, or that the tranformer is exhonerated from culpability. No un-soldering necessary at this point, which begs the question, did either of the other two techs do this? (I kind of doubt it, if they didn't charge you for the diagnostic. If they did charge you, then they should have done this little test.)

OK, that's it for now..... PUNT! The ball's back in your court.


sumgai

[pollyshero]

I ordered a reverb transformer from here www.crateamps.com/support/index.php The "Crate Parts Professionals" link will take you Loud Technologies (Mackie) who supply the Crate replacement parts.

I inquired as to availability. A week went by & I received an email stating that the part was in stock, but I'd have to call the 800 number to order. I called, spent 20 or so minutes on hold and ordered my part. Waited a month & received an email that the part was on back-order. 2 weeks later I got the part.

Maybe you'll have better luck...