Egnater Tweaker 15 repair and schematic request

[Steelwitch]

Hi y’all,

I have an egnater tweaker 15 on the bench that’s blowing the 1.6a mains fuse at very low voltages.. something like 50vac will fry it. I have a feeling it’s in the power supply. I can’t find a schematic that includes a power supply. Does anyone here have one? There’s a lot of threads about PT’s with open windings on these. The problem persists with all tubes removed. The layout of this amp is pretty dizzying especially with a schematic of only input and output stages. How would y’all approach a repair like this? What tests can be done passively without going through and testing everything in the power section. Or at least determining if it’s a transformer or not. I understand there might not be shortcuts, but let me know what y’all think especially if you’ve worked on these before. Thanks!

[Steelwitch]

It occurred to me also that it could be the output transformer, only because before switching anything around, I observed that the impedance switch was set to 8ohm when the stock speaker in these is 16ohms. So, who knows how long the customer ran it like that. Kind of a weird detail

[xtian]

Disconnect all PT secondaries from the circuit. Still blows fuses? Then obviously PT is shorted.

[The Dude]

https://el34world.com/charts/Schemat...tweaker_15.pdf

[J M Fahey]

To test transformer on its own clip/unsolder/unplug and safely tape all secondaries so none is connected to any load, plug amp into a lamp bulb limiter (search it here) with a 40 to 75W bulb and turn it on.

If lamp glows as bright as straight to the mains,transformer is shorted dead; if not, then problem may be downstream.

[SoulFetish]

To test transformer on its own clip/unsolder/unplug and safely tape all secondaries so none is connected to any load, plug amp into a lamp bulb limiter (search it here) with a 40 to 75W bulb and turn it on.

If lamp glows as bright as straight to the mains,transformer is shorted dead; if not, then problem may be downstream.

Just a heads up, there was an entire production run of these which are know to have faulty power transformers. Do what JM Fahey suggests regarding testing the power transformer. If you don't have an incandescent bulb limiter, monitor the mains current while bringing up the variac. I find it's best to use a moving vain panel meter for this as it is a better visual indicator of what's happening. The response is faster than digital read-outs for this kind of testing because digital meters will lag due to processing time from constantly recalculating under fast changing conditions.
*Making sure all the secondary leads are open and there is no secondary load at all–If the meter indicates an increase in current (measuring in amps) at about the same rate as you increase the variac voltage to 5, 10, 20V, then the transformer is shorted.
If the transformer test okay, then a shorted rectifier would be the next thing I would check.
If the transformer is faulty, then check back we can talk about what you, or the customer might want to do at that point. I just went through this on a Tweaker 15W head a couple of months ago. Good luck

[Steelwitch]

I disconnected all secondaries and the fuse still blew! Looks like it’s a bad PT— that’s a shame!

[Steelwitch]

It might be a dead amp forever, the customer can’t really afford a replacement plus labor. RIP

Does anyone know if there’s any kind of active recall for these? It looks like this problem is really common, it’s hard to believe egnater let a line of amps out there with faulty transformers

[xtian]

Just call Egnater on Monday and ask.

[glebert]

I replaced a PT on an Egnater Renegade. Since it was out of warranty (and I was not original owner) I had to buy it for a price that I found pretty high considering they had sent out crappy hardware in the first place. Ordering was a pain as well (had to fax credit card number or use Paypal and pay an extra 3% IIRC). I got the amp for $50 as a fixer so I still did OK on it, but was not super impressed by their customer service.

[Jazz P Bass]

"Does anyone know if there’s any kind of active recall for these"

No.

Bruce is in denial.

[SoulFetish]

When I replaced the PT on a Tweaker 15 head a few months back, I had to speak to Bruce directly to get his distributor to respond to my request for a quote on the cost of a new PT and shipping.
Bruce was quick to respond and accommodating, but the distributor... (I forget the name of the top of my head at the moment), pretty much sucked to try and deal with.
Plus, when the distributor finally got back to me with a price for the available Chinese PT replacement, it was way overpriced. Bruce was nice enough to provide the specs to have a custom transformer wound, as I thought it was a better value ultimately and probably cheaper. But, our shop is a Mercury dealer and turns out, they were the cheapest option (go figure).

[Steelwitch]

Yeah! They tried to charge me $190 for a PT and they kind of acted like I didn’t know what I was talking about when I told them a mercury magnetics replacement is $170. Idk, after dealing with customer service I don’t think I could recommend egnater to anyone, and after seeing how they’re built it’s definitely not something I would buy, but to Bruce’s credit I can understand it’s tough to manage these things when your business grows bigger than a shop

[alexradium]

get a local transformer professional rewinder and he will make you a new one for less money and much better quality,just give him the specs for each winding.

[SoulFetish]

You may find this helpful.

TWK15_PT_and_Schematic.pdf.zip