Voltage selector with 120v lamp, blowing mains fuse

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b0b138
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Posts: 2
Joined: Thu Sep 27, 2018 9:04 pm
Just the numbers in order: 13492

Voltage selector with 120v lamp, blowing mains fuse

Post by b0b138 » Sat Oct 20, 2018 3:13 am

yes... I am in over my head :lol:

So I get to the second step of testing, turn main to on, blow mains fuse.

I am not 100 percent sure I’ve wired the voltage selector right as I never found a diagram with a 120v indicator lamp.

I’ll post a pic but explain what’s what in case it’s not clear. These are metro spec PT and OT

I’ve got the brown orange yellow wires going to the selector. The common (orange) is to the power switch.

The black from the PT goes to the lamp, then a black wire to the mains fuse.

There’s a brown wire from the 120v/brown of the selector to the other side of the lamp.

After looking and looking but not seeing something wrong, I pulled the brown wire from the lamp, assuming this should remove it from the circuit. And :champ: I could take some voltages. So from step C of testing...
I got 3.37 on v1 2 and 3 pins 4 and 5 (I’ve realized afterwards there are several other pins to check also but didn’t...I got excited lol).
From step D there’s -26 to -40
And from step E, 312

I stopped here cause I want to get the indicator working before going further.

So it seems that from what I have checked, voltages are within range. AFAIK anyways.

I tried switching the wires on the lamp as one side was marked with a + and I’m not sure if it matters but that blew another fuse.

Thanks in advance for any help.

https://share.icloud.com/photos/0MVA5GB ... bjPeguSAJg

b0b138
New Member
Posts: 2
Joined: Thu Sep 27, 2018 9:04 pm
Just the numbers in order: 13492

Re: Voltage selector with 120v lamp, blowing mains fuse

Post by b0b138 » Sat Oct 20, 2018 11:27 am

Oh, and it’s not a Marshall style lamp. It’s s fender one.

https://www.tubesandmore.com/products/l ... relampable

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