R.I.P. Engl Invader 150?

[Randyisgod15]

Alright, so here's my story/predicament. I bought an Engl Invader 150 off craigslist for $1400 at the beginning of the year. I had it for about 4 months, thing sounded beast, worked great as far as I knew. Then one day I was shredding a lick and POP! That was the end of that. The only faint flicker of life comes from a dimly lit power switch. No tubes, lights, nothin'.

So instead of bothering to open it up and do some self inspection (being at the time I had little self-confidence in my technical abilities) I brought it to my local shop I've been going to for a decade, who have done good by me thus far. Long story short, after being dicked around for over 3 months with every excuse in the book, the "diagnosis" was a busted power transformer, with a repair cost of almost $600. I declined the repair, and finally have it back here.

Now I'm not the most tech-savy person, but until I can confirm this myself, I'm not gonna roll over and let this amp die on me. After being shafted by the shop I really can't take their word for it because.....who wouldn't wanna make $600 heh. I'm gonna crack this baby open on my day off tomorrow and do some investigating with my father, and see what the deal is.

What do you guys think of this? Does it sound like a dead power transformer? Could it be something much less serious tripping up the whole amp?
What should I be looking for specifically when I open it up that would be a tell-tale indicator?

The lesson I am taking out of all of this is to learn to be more self reliant when it comes to self-educating myself about the gear and technology I buy. I've been doing some research the past few months, but not having the amp here at the time didn't help. Thanks in advance for taking the time to actually read through this and any help/advice you can offer would be much appreciated.

 

[TheWinterSnow]

EDIT: I saw you said the lights (LED) are out too, may be the PT, check the main fuse first, if its fine its most likely the PT but you can follow my instructions below although they should't be of any help most likely. I don't have a schematic of the amp so I have no clue how its wired, but the power switch lighting up makes me think something is working unless that light is main voltage (120v) neon bulb placed between hot and neutral after the power switch which I think is the case. Even if it is the OT you should be able to get a replacement in the $200-300 range and if you can do it yourself or have someone do it cheap you save a lot, $600 is fucking crazy.

The first thing you can do is be sure that the heater filaments on the tubes are glowing, if they are the PT could either be ok or partially fried. The next thing you can do to check if the PT is fried is to locate two leads where the PT hooks up to the mainboard, where there are 4 diodes, large filter capacitors and generally some sort of lead connecting that circuit to the standby switch. This is the HT rail that powers the anodes of every tube in the amp, if it has no voltage then you have a fried PT, if you have a large voltage ~500v, then the PT is fine. If you do have a voltage the first thing I would look at are the fuses, if they are fine, check to see if the anodes of any of the tubes are getting power.

Do that and report back in. And do be careful about where you put your hands and use the one hand in your pocket when probing around in there if you want to live when the amp is live.

 

[Sloan]

If your amp under any type of warranty go through that process first and get a replacement or repair.

The only faint flicker of life comes from a dimly lit power switch.

If this means that the power switch lights up, then I would not suspect a power transformer. The only power transformer I've had to replace was on an Epiphone Valve Jr. some dude had modded himself, he got a new pcb board that added a tube and needed a more powerful than stock transformer. Transformers going out are rare and I have a hard time believing that in something like an ENGL they wouldn't have protection via fuse etc...

As far as I know, regular shop rates are about $50 an hour with a flat rate $50 bench fee just to look at it. I'm guessing it would take at most 4hrs to remove and replace the power trans ($200). That leaves $350 for parts cost. Now, if both your power and output transformers blew, then that leaves about $175 per transformer, which sounds about right. On the Mercury Magnetics page, the only ENGL transformer I found was $195.

Call/Email ENGL and see if they will price the transformers for you and also email you a schematic. This will help you determine if the shop is cutting you a good rate or not.

 

[Empathy]

As said above, sounds like blown fuses, not a dead tranny. Check/replace fuses, and check them power toobz.

 

[Randyisgod15]

So long story short, my neighbor who has been dealing with tubes and electronics his whole life came over to investigate and there's not a damn thing coming off the power transformer. He's just baffled as to why the fuses are all good and the transformer is toasted. I'm trying to get the schematics from ENGL, but no response as of yet. Oddly there was a burnt out looking part of the board, and there were a series of leads unsoldered from the board as well. Until I get the schematic, he didn't want to go too far and start pulling the whole board out and whatnot until he knew what was going to be behind it. One of the EL34s was cracked, which is definitely not how I gave it to the shop, but I'll just get another one and that's that.

So that's where I'm at. Waiting for the schematic, and trying to find a replacement transformer. No luck as of yet, and Sloan I saw the Steve Morse transformer you were talking about. Not sure if it's the one I need or not. Where should I be looking for a replacement transformer. This is my first "real" tube amp and I'm new to this whole universe of electronics (you know, actually becoming knowledgeable and not just tossing everything off to someone else to fix.)

While I'm at it: What are some good resources to start some quality self-education on tube amps and electronics? I know hands-on experience is best, but something not so mind-blowing and over-the-top that I can digest and get a firm mental footing on the subject.

 

[TravisW]

Check out www.ax84.com. Their theory document alone is very worthwhile, even if you don't build any of the kits.

 

[lolzgreg]

Power transformers are amp specific; output transformers are GENERALLY not; they are wattage and tube specific for the most part. Getting replacement parts from Engl SUCKS; they are overpriced as shit.

 

[Sloan]

Look at the markings on the transformer and go from there.

 

[MarcusGHedwig]

Wow dude, so this is still going on, my sympathies and best wishes! A busted power transformer, fuck, how does that even happen? (I thought it was the output transformers that were more likely to get fried from such abuses as running the amp fully-on AKA off of standby without a cab or other load connected). But yeah, shit's gay

 

[no.mop]

One of the EL34s was cracked, which is definitely not how I gave it to the shop, but I'll just get another one and that's that.

I'm sure you know, but you need to get a matched pair; you can't just buy a single EL34 and pop it in.

 

[kaomao]

check the fuses on the main board as well, on my peavey and mesa there are fuses over there, not just the ones on the back