Fender Blues Jr. doesn`t turn on

[greggar]

Hello,

I'm using my MIM Blues Jr. in Spain (cream board, 60th anniversary edition) . Till now I've been using a stepdown transformer, but last week after sound check i went to the bathroom and when I returned the amp was dead.

I'm guessing there was a tension issue that fried the PT... but just to be sure: any measures to follow to confirm this? Both fuses seem to be ok (mains and heater).

I'm about to buy a replacement PT, OT and choke from Mercury Magnetics (itīs the only one I've found available here in Europe) but it's rather expensive... so if anyone can shine a light on a better option, please be my guest.

Thanks in advance,

Greg

[Jazz P Bass]

Maybe you could start at the step down transformer.
Is it supplying the 120Vac to the amp?
If it is, I would suggest removing the output tubes and actually checking the transformer secondary voltages.
The B+ & the heaters.
If all is good, & putting back the output tubes does not drag anything down, then you need to track down where the failure is in the signal path.

[greggar]

Well, I checked the stepdown I was using... The reading's 142 (On the 120 side). Maybe too high? I would think that's still tolerable... Is it? I'm guessing it may be a sign that it's not working appropriately and maybe allowing higher peaks at given moments.

I'll open up the amp tonight and make the other readings. What should it be on B+ and the heater?

Gracias!

[52 Bill]

The first test I would suggest is to take an ohm meter reading across the Hot and Neutral side of the ac plug. When the switch is turned on you should see the relatively low ohm reading of the transformer's primary winding.

If you don't get this reading, check the ac switch and the fuse holder for continuity. Then test the transformer itself.

[big_teee]

The first test I would suggest is to take an ohm meter reading across the Hot and Neutral side of the ac plug. When the switch is turned on you should see the relatively low ohm reading of the transformer's primary winding.

If you don't get this reading, check the ac switch and the fuse holder for continuity. Then test the transformer itself.

You might **Caution to make sure it's not plugged in when you do this!
There are different levels of Safety and knowledge base on this Forum!
T

[52 Bill]

Maybe I should have been clearer on this, but I meant to take the readings at the plug end of the ac cord, which would make it hard to do when it's plugged into a wall socket. This will also check the ac plug and wire for continuity as well.

Thanks for the warning, anyway.