JTM 45 build

[MikeT]

I just finished a JTM 45 kit from Mojo and there are issues. The b+ is near 500VDC at all b+ points with just the GZ34 in. Granted, the pre and power tubes draw current, but isn't this a bit high? When I put the pre's and power tubes in I got smoke from the middle of the board. I had them in before and got no smoke but very high b+ readings in the preamp. like 300 +. But this time when I got smoke I immediately shut it down and checked continuity fro the board to the tubes and the board to the pots. All were fine. I just don't know what to do next....Any ideas? Thanks guys....

[big_teee]

Some gut shot pictures would help.
Also Metro has an instruction manual you can download, that has a power up section.
TubeDepot has one too.
They show voltages with and without tubes.
Here are the links to the manuals.
http://metroamp.com/wiki/index.php/J...t_instructions
http://metroamp.com/wiki/index.php/5...t_Instructions
http://site.tubedepot.com/pdf/jtm45plus_v4a.pdf
http://site.tubedepot.com/pdf/jtm45plus_v4b.pdf

[MikeT]

Some gut shot pictures would help.
Also Metro has an instruction manual you can download, that has a power up section.
TubeDepot has one too.
They show voltages with and without tubes.
Here are the links to the manuals.
Jtm 45 kit instructions - MetroAmp Wiki
50 Watt Kit Instructions - MetroAmp Wiki
http://site.tubedepot.com/pdf/jtm45plus_v4a.pdf
http://site.tubedepot.com/pdf/jtm45plus_v4b.pdf

I've got those manuals, but thanks anyway. I have a couple pics but I can't get this bb to upload them. I click on "Insert Image", navigate to the image, and it just hangs.......

[big_teee]

So are your voltages similar to the Instruction charts?
Maybe that will show you where your problem or wiring error might be?
T

[MikeT]

Terry,

I can't check the voltages with the tubes in because the board starts smoking...not good! I have a feeling it is a problem underneath the board, because there was continuity to the chassis where there shouldn't be.

Mike

[big_teee]

Terry,

I can't check the voltages with the tubes in because the board starts smoking...not good! I have a feeling it is a problem underneath the board, because there was continuity to the chassis where there shouldn't be.

Mike

Roger that Houston!
May be a good time to build that Dim Bulb tester.
They are great for what I call Poor Boy Power up!
dim bulb tester - Google Search
Good Luck,
T