5F1 - Low Sound output

[nesma02]

Hi,

I am on my first build - I fixed one issue caused by some bad documentation but now I am getting next to nil sound output. I have been reading some other posts that point to the voltage leading to the answers. I measured the following in DC:

rectifier pin 8: 380
power pin 3: 365
power pin 4: 342
power pin 8: 21.5
preamp pin 1: 308
preamp pin 6: 297
preamp pin 3: 3.38
preamp pin 8: 3.18

Based on what I have read in other posts, it seems like the preamp tube is 2x what it should be - any idea why?

Thanks,

[loudthud]

With the power off and the caps discharged, measure the resistance to ground on pins 3 and 8 of the 12AX7. It should not be higher than about 1500 ohms. Also with no plug inserted into the input jacks, the resistance to ground on the first triode should be 34K and on the 2nd side a variable resistance changed by the Volume control.

[nesma02]

With the power off and the caps discharged, measure the resistance to ground on pins 3 and 8 of the 12AX7. It should not be higher than about 1500 ohms. Also with no plug inserted into the input jacks, the resistance to ground on the first triode should be 34K and on the 2nd side a variable resistance changed by the Volume control.

ok - I clipped the black to the chassis, set the Ohms to 20k and got 9.00 on the 8 pin and 15.64 on the 3 pin.

You lost me on the second part - not sure what you are referring to with the 'first triode' and '2nd side' on the jacks.

[loudthud]

The Fender schematics don't typically have pin numbers on the tubes so I don't know which side of the 12AX7 is connected to the input jacks and which side is connected to the volume control. By first side, I ment the side connected to the input jacks since that is the first tube that the signal goes through. The next tube the signal goes through is after the volume control just before it goes to the 6V6.

15K tells me you used the wrong resistor. It should be 1.5K, brown, green, red, (silver or gold) not brown, green, orange (silver or gold). Sometimes it hard to tell red from orange on old resistors, if you are unsure, a quick check with an ohm meter before you solder the part in will save time in the end.

[nesma02]

The Fender schematics don't typically have pin numbers on the tubes so I don't know which side of the 12AX7 is connected to the input jacks and which side is connected to the volume control. By first side, I ment the side connected to the input jacks since that is the first tube that the signal goes through. The next tube the signal goes through is after the volume control just before it goes to the 6V6.

15K tells me you used the wrong resistor. It should be 1.5K, brown, green, red, (silver or gold) not brown, green, orange (silver or gold). Sometimes it hard to tell red from orange on old resistors, if you are unsure, a quick check with an ohm meter before you solder the part in will save time in the end.

I swapped one resistor so far and the sound has already gone up considerably. still not there yet but definitely on the right track. I am going to swap out the other two that seem to be off the spec sheet and hopefully I am all done. I appreciate the assistance in getting me looking at the right spot. The kit came with the resistors bagged & labelled individually - definitely a learning experience not to take anything for granted.

[Meaux]

I swapped one resistor so far and the sound has already gone up considerably. still not there yet but definitely on the right track. I am going to swap out the other two that seem to be off the spec sheet and hopefully I am all done. I appreciate the assistance in getting me looking at the right spot. The kit came with the resistors bagged & labelled individually - definitely a learning experience not to take anything for granted.

You can say that again...

[nesma02]

.... So it was two 1.5k resistors that were shipped with the kit that were actually 15k resistors - Orange stripe instead of Red. I swapped those two out and I have a Champ. Many thanks for the advice and on to the next one.