How hard is repairing a 5150iii?

ners

ners

Well-known member
Saw a busted one on FBM and considering it being my first attempt at amp repair. I'm mediocre at using a soldering iron and have been glancing at random schematics lately. Doubt I could actually design/improve anything but the repair estimate calls out some basic cap and resister replacement which I'm assuming I can simply desolder/resolder?
3258.jpg



Tube/fuse is simple and I've done before, but this would be my first amp solder...good starting point? If this estimate requires any additional troubleshooting I'd probably be screwed.
 
Which caps and which resistors need changing? You’ll probably need troubleshooting skills to determine which ones.
 
Which caps and which resistors need changing? You’ll probably need troubleshooting skills to determine which ones.
Filter caps (3 of them) and the screen grid resistors (4 of them), according to the footnote in the estimate the owner sent me.
 
Filter caps (3 of them) and the screen grid resistors (4 of them), according to the footnote in the estimate the owner sent me.
Ah I didn’t read that far!

Potentially could be some solder pad or trace damage with burned resistors.

My experience with large radial caps is they can be hard to get off sometimes, can be tricky to suck all the solder out of though-plated holes, especially if they’re glued down. You’ll need the lead spacing of caps so you can buy the right size.

Could also be other things wrong but you won’t know until the power amp is fixed.
 
Ah I didn’t read that far!

Potentially could be some solder pad or trace damage with burned resistors.

My experience with large radial caps is they can be hard to get off sometimes, can be tricky to suck all the solder out of though-plated holes, especially if they’re glued down. You’ll need the lead spacing of caps so you can buy the right size.

Could also be other things wrong but you won’t know until the power amp is fixed.
Yeah that's the gamble given my lack of experience. He has it listed for $500 but I was thinking if I could talk him down my worst case scenario would be doing all those repairs and then maybe bringing to a tech to finish troubleshooting (with the hope it's not a crazy fix).

From googling it seems screen grid resistors failure is common with failed tubes? And presumably the caps leaking is age? Not that the EVH 5150iiis are that old...
 
Honestly, the biggest pain out of all of this is getting the damn board out of the chassis. From what I remember, if they are the 3 axial caps on the main preamp board, it's huge and it's a pain because a lot needs to be disassembled to even get to underneath the pads to remove them cleanly. Next, you'll need to be very thorough with your solder removal as I believe they used lead free solder on those models - unless you're already using lead free solder. In which case, you'll want to be very careful with your heat to not blow any traces. None of it is necessarily "hard" work, but it's just tedious.

My main question would be - are you sure that estimate covers everything that's wrong with it and will solve the issue? Or is that just the first attempt at resolving any issues with the amp, and you'll need to debug further from there? The 100w is a lot easier to work in compared to the 50w, so it's not necessarily a bad project to start with. Take lots of pics, go slow, but also realize what you might be getting into. Worth noting the labor estimate you posted is definitely fair if that's the work that needs to go into it. Most of the cost is just the tubes themselves, and you can possibly get them cheaper at Eurotubes to help reduce costs.
 
Not a terrible price but, not a tough repair either.

Which amp is it? Is it worth putting $600 into?
 
@Code001
Not sure, but was estimated by a reputable shop by me which eases some of my concerns; but obviously always the risk they missed something. Yeah it's the 100w so I assume more space to work with.

@Geo
EVH 5150iii 100w 6L6. No resonance pot on front or back, so I assume an older (not sure what year they started adding that). Reverb shows a few of them going for $850ish every other month, so between his $500 cost and $600 repair estimate he's probably asking for mid to high range.

Despite the 5150 being the amp of my 90s childhood, I've got enough high gain Marshall's that I don't lust for this amp...but for a cheap price and starting a new hobby it seems it might be worth it.
 
@Geo
EVH 5150iii 100w 6L6. No resonance pot on front or back, so I assume an older (not sure what year they started adding that). Reverb shows a few of them going for $850ish every other month, so between his $500 cost and $600 repair estimate he's probably asking for mid to high range.

Despite the 5150 being the amp of my 90s childhood, I've got enough high gain Marshall's that I don't lust for this amp...but for a cheap price and starting a new hobby it seems it might be worth it.
I would say try putting the tubes and caps in yourself or buy a new one.
 
$850 for a 100w EVH? That's a crazy good deal for that amp. I normally see them closer to $1200, and I would use that as my "baseline".
 
Wow, that repair quote is actually a great deal. If that dude is only charging 1 hr labour to change out the filter caps and screen resistors, I'd grab the amp and run down there before he changes his mind.
I've worked on a few of these and I don't think I could do that job in an hour.
The other thing to consider is when you buy a used amp, you should always assume that you're gonna have to re-tube it, so when you subtract the cost of the tubes, the actual repair is chump change.
 
$850 for a 100w EVH? That's a crazy good deal for that amp. I normally see them closer to $1200, and I would use that as my "baseline".
Yeah, I was gonna coment on pricing for these:
I'm up in Ontario, Canada, and I can't find a used 100watt og 5153 for less than 2k, which is about $1300Usd.
$850usd would be a great deal.
 
Yeah $850 is on the low end, so I think everyone else's valuation is probably closer to the average.
3266.png

I've been good lately about negotiating low balls, every few months getting something for 10% below the lowest Reverb price in the last 6 months.

It's sounding like if I can negotiate a good price this is worth it regardless if I do the work or not.
 
  • Like
Reactions: Geo
Back
Top