cant seem to figure out the pt wiring for my express

[72fetter]

its from a jtm45 style
i cant seem to figure out the power switch wiring cuz it sparks right when i plug it in

[72fetter]

let me clarify lol....I am an amateur builder and cant seem to figure out what goes where

[Structo]

First of all, where are you located and what is your wall voltage?

[72fetter]

In the us
120v

[mcrracer]

That is one of the better tranny wiring diagrams. This is scary. Are you following a schematic for a particular build? How have you wired it in? Pictures? Is it a solid state or tube rectifier? Makes a difference.

[72fetter]

I currently ran the input for the pt to one side of the power transformer and the positive power side of the mains to the other.
its a solid state rectifier

[72fetter]

here is the layout i am going off of.
the power switch is just a two pole like the one shown for the standby switch

[72fetter]

ok looking at my pt digram
i am assuming my pt primary is the orange input wire and the black wire is my 120 v wire?

[paulster]

Your mains input should go to orange and red wires on the primary side. The white/pink, brown, blue and violet wires on this side should all be capped off safely.

On the secondary side you want to cap off the two white wires since you aren't using a tube rectifier.

Yellow and green/black go to chassis ground.

The two blue ones are your HT supply and the two green ones are your heater supply.

Note that this is a 385-0-385V transformer whereas the Express is designed around a 300-0-300V transformer, so you'll have massively high voltages.

[mcrracer]

I currently ran the input for the pt to one side of the power transformer and the positive power side of the mains to the other.
its a solid state rectifier

The input of the PT to one side of the power transformer??? This does not make sense to me. busy layouts hurt my eye. I am partially blind but can see well enough to build tube amps very well. Can you trace the hot side of the AC from the AC cord thru the fuse to the power switch then to the input of the PT red ( 120V) The white wire goes to (orange was it) Your high voltage then goes to your rectifier. You will have to google up a diagram or look at the schematic. That is why I use schematics...they are the road map for the amp. Have you built any amps before? Just trying to ascertain your skill level. I don't want to assume you know something that you may not know. Safety first.

[72fetter]

sorry i meant switch
.I have built a couple of amps that all worked fine but i am only familiar with layouts unfortunately

[72fetter]

ok so heres the update.
-when plugged in with no power tubes but preamp tubes in it powers on no prob and the pre tubes warm up.
-when i plug in the power tubes and connect it to a cab-it sparks and the power tubes light up.
-these are new power tubes

[72fetter]

btw it only does this when switching from standby

[paulster]

What sparks?

You need to resist the temptation to power this on again until you've established what's actually wrong as you risk the power transformer, blowing up filter caps, or even your life.

How about posting some detailed, high resolution photos so that we can take a look at this and try to get to the bottom of it without any damage.

[Structo]

Did you know that anytime you power up an amp with power tubes installed that you must have a speaker load connected or you can lose your output transformer and or your power tubes?