HELP!! Tubes 1-5 wont heat up.

[mjunkieguitar]

I completed a build on a Metro 100 watt kit about a week ago. It sounded fine when I fired it up but after about an hour of play it started to get some intermittent scratchy and poppy sounds through it, especially when playing lower notes. I shut her down and took out the tubes to see if there was any residue in the pins. I put the tubes back but NO SOUND!! I then noticed that all 3 pre's and the first 2 output tubes were not heating up. Tubes 6 and 7 do. I took them all out and went back to checking my voltage. Fuses are good.

With only the power on:

Tubes 4-7, pin 2 & 7 showed 3.5 VAC
Tubes 1-3, pin 4,5&9 showed 3.5 VAC

With standby on

Tubes 4-8, pin 3 and 1k resistor showed 508 DCV.

These are a little high, but in the ballpark I think. I threw new tubes in and still nothing despite getting the above voltage readings. What would cause this?

[Twist]

I would check for poor soldering joints on all your filament wires. They may look good but I would reflow the joints again.

[mjunkieguitar]

Got home from work and stuck my nose in the chassis. I started checking voltages again and prodding around the heater wires with a chopstick. I noticed the pre's lit up so I threw in the EL34's. They went out again and came back and stayed. I think the solder joint from tube 5 to 6 was bad so I am going to re-do them. Also poked around the board and there was some static. Does this also indicate a bad joint on that particular cap/resistor? Voltages seemed closer to normal except V1 pin 1 just over 200. Any ideas?

[Alex R]

Components in early stages will be a little microphonic if you tap them. Bad joints tend to make big crackles and maybe overall changes in the sound as you move a component to and fro.

Preamp plate voltages may read 200, but it's high. Unless there's no tube in there when you measure?