Tweaker 15 head blows main fuse

M

Mullet

New member
As soon as I turn the amp on, the fuse blows. Same thing happens also after removing the secondary fuses and disconnecting the filament voltage. I understand this indicates the power transformer is broken. I have also understood this somewhat common. Anyone here with the same experience? What did you do? What PT can I use to replace the broken one? Or is it possible to get one from Egnater? I have read about Mercury magnetics PT, but it is a little pricy.

Thanks
Thomas
 
Mullet":1s5bfrsg said:
As soon as I turn the amp on, the fuse blows. Same thing happens also after removing the secondary fuses and disconnecting the filament voltage. I understand this indicates the power transformer is broken. I have also understood this somewhat common. Anyone here with the same experience? What did you do? What PT can I use to replace the broken one? Or is it possible to get one from Egnater? I have read about Mercury magnetics PT, but it is a little pricy.

Thanks
Thomas
Click to expand...

Did you remove the tubes and power it on. Could just be a shorted output tube.
Contact Egnater before buying a transformer. Maybe it's under warranty.
As far as power transformers, you may want to contact Classic Tone and see if that have a transformer that will work for you. Mercury Magnetics makes a nice transformer, but are IMO seriously overpriced.
 
No, I did not remove the actual tubes, only the fuses. I'll try to remove the tubes and see what happens.

Thanks.
 
Hi
I have helped Mullet with this Tweaker 15 amp.
I have measured resistance in the secondary high voltage windings and one of the windings has half the resistance of the other. It is internally shortcircuit ..
I have also sent a question to Egnater about the spec on the Power Transformer to be able to find a replacement here in Sweden or Europe.
The freight cost, import duty and sales tax for a transformer from US to Europe is nearly 100 USD ...
The only "standard" transformers available in Europe and Sweden is Hammond.
They have a PT for Fender Deluxe Reverb (6x12AX7 & 2x6V6) that might be possible to use = 290 BEX.
Kalle Sandberg (also an owner of Tweaker 15)
 
Hi Guys
After many failed attempts to get in contact with Egnater or Bruce himself about where to buy an originial PT, I searched the web for a replacement PT and found this Toroid PT for a 18W amp.
http://www.tube-town.net/ttstore/Transf ... :3840.html
It has all the neccesary windings and right voltages.
Today we installed it in the amp and it worked like a charm.
B+ just a little bit higher than normal (390VDC compared to 375 VDC)
We also changed the cathode resistor R29 from 220 ohm to 510 ohm(value in the latest version of tweaker 15).
And the installation looks like this
Tweaker%2015%20with%20Toroid%20PT4.jpg

Tweaker%2015%20with%20Toroid%20PT3.jpg

/Kalle
 
I might add that this PT only allows 220, 230 or 240 V. Hence the backside switch for 100, 117 or 230V is not possible to use anymore, it is now a fixed value of 230V. Not a problem for me since I live in Sweden, and if I all of a sudden have to tour in US I might treat myself to a new amp ;)
 
Here is information on the original Egnater Tweaker 15 PT

Primary windings
1; Brown - Black (113 VAC)
2; Black-Blue (17 VAC)
3; Blue - White (100 VAC)

For 230 VAC use :
Brown and White cables connected to 230 VAC
For 117 VAC use :
Black and White cables connected to 117 VAC
For 100 VAC use :
Blue and White cables connected to 100 VAC

Secondary windings
1; Red-Black-Red ( 290 VAC - Center Tap - 290 VAC)
Connections on circuit board = QC8 -- QC10 -- QC9
2; Green-Black-Green ( 3.15 VAC - Center Tap - 3.15 VAC) Heater
Connections on circuit board = QC23 -- QC3 -- QC20

Dimensions:
Height = 83 mm
Width (X) = 88 mm
Depth (Y) = 96 mm

Mounting holes : = 6x10 mm (X-direction)
X-direction = center-center = 60 mm
Y-direction = center-center = 80 mm
 
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