Please help with my first build 5F1 with no sound

[tubeswell]

0.542V Or do I need to plug it in and turn it on ?
oh its now 0....

It should be 6.3VAC. The heater can't be working. In the pic of your wiring to the lamp holder, the way you have them wired suggests that there's no connection between the 2 lugs on either side of the lamp holder. Try soldering a bit of wire between those two outside lugs (with the lamp removed of course). (Don't change anything about the end lug at this stage)

The other thing is, have you grounded the PTs' heater winding centre tap? (does the heater winding even have a centre tap?)

[icy_wind500]

It should be 6.3VAC. The heater can't be working. In the pic of your wiring to the lamp holder, the way you have them wired suggests that there's no connection between the 2 lugs on either side of the lamp holder. Try soldering a bit of wire between those two outside lugs (with the lamp removed of course). (Don't change anything about the end lug at this stage)

nono I didnt turn on the amp before
now that its on, its now 6.82

[tubeswell]

Well then maybe its still gotta be something not right on the back of the board.

Is there any sound out of the speaker with the amp on (a faint hiss or hum?)

[icy_wind500]

Well then maybe its still gotta be something not right on the back of the board.

Is there any sound out of the speaker with the amp on (a faint hiss or hum?)

not really .... in that case.... I'll pull the board out again....
I'm just worried its the transformers
So what do I do after I pulled it out?

[telenut62]

Well then maybe its still gotta be something not right on the back of the board.

Is there any sound out of the speaker with the amp on (a faint hiss or hum?)

This was an earlier pic, I think he's reflowed since then....

http://a6.sphotos.ak.fbcdn.net/hphot...79728901_n.jpg

It's poss there's a wire been trapped and shorting? but it would have shown up by now, all I can think is there's a component fault somewhere.

[icy_wind500]

This was an earlier pic, I think he's reflowed since then....

http://a6.sphotos.ak.fbcdn.net/hphot...79728901_n.jpg

It's poss there's a wire been trapped and shorting? but it would have shown up by now, all I can think is there's a component fault somewhere.

yes I've reflown all the joints at the back and insulated with a piece of cardboard from the box the kit came in

[tubeswell]

Checking the PT is simple. If the PT is making ~6.3 VAC or so between each end of the heater winding, and ~650VAC or so between each end of the high tension winding, and 5VAC or so between each end of the rectifier winding, it'll be fine.

To check the OT, you need to unhook the OT primary and secondary windings completely from the rest of the circuit (with the amp off and unplugged), and hook each side of the secondary directly up to one side each of PT's 5VAC winding, and then (making sure the now-unconnected OT primary wires are not touching anything else) switch the amp back on and carefully measure the VAC across the OT primary. Make sure the OT secondary and the PT primary are not contacting/shorting to any part of the chassis or the amp's circuit when you do this. Its best to use insulated gator clips to hook the VAC meter up to the OT primary, and its best to use mains-rated insulated screw connectors to hook the Ot secondary to the PT 5V winding. The VAC between each end of the OT primary winding should be 160VAC or so (assuming it is an 8k:8R OT) with about 5VAC applied to the secondary winding. (Make sure your meter is on the 'hundreds of volts AC' setting to measure this)

The point of taking the board out is to check the wiring on the back of it throughly, and also to make sure the back of the board is properly insulated/separated from the chassis.

[icy_wind500]

Checking the PT is simple. If the PT is making 6.3 VAC between each end of the heater winding, and 650VAC between each end of the high tension winding, and 5VAC between each end of the rectifier winding, it'll be fine.

To check the OT, you need to unhook the OT primary and secondary windings completely from the rest of the circuit (with the amp off and unplugged), and hook each side of the secondary directly up to one side each of PT's 5VAC winding, and then (making sure the now-unconnected OT primary wires are not touching anything else) switch the amp back on and carefully measure the VAC across the OT primary. Make sure the OT secondary and the PT primary are not contacting/shorting to any part of the chassis of the amps circuit when you do this. Its best to use insulated gator clips to hook teh VAC meter up to the OT primary, and its best to use mains-rated insulated screw connectors to hook the Ot secondary to eth PT 5V winding. The VAC on the primary should be 160VAC or so (assuming it is an 8k:8R OT)

Checking PT, between heaters (green) is 6.83V AC, (yellow) is 5.07V, (red and white) is 579V

[tubeswell]

Checking PT, between heaters (green) is 6.83V AC, (yellow) is 5.07V, (red and white) is 579V

I thought on the other forum that you said the high tension winding measured 670? Was that another PT? ~580VAC centre tapped is 290-0-290VAC, which will get you about 320VDC B+ with a 5Y5GT rectifier.

650VAC (which is 325-0-325VAC with the center tap) will get you around 360VDC B+ with a 5Y3GT rectifier.

[icy_wind500]

I thought on teh other forum that you said the high tension winding measured 670? Was that another PT?

That multimeter was bad so all the voltages were wrong

[telenut62]

It's the lower 550V secondary on the Classictone PT

[tubeswell]

Is there a higher secondary on that PT?

[telenut62]

........630V

[icy_wind500]

the red one I think

[tubeswell]

I'd use the 630 winding

(Its getting late here guys and I've got work in the morning - I'll catch up with you tomorrow)

Pete