5e3 problem - low output!

[ben85]

you were all right,it must have been a bad joint.so,i measured again and the results are

V1:
PIN:
1: 172v, no click
2: 0v, no click
3: 1v, no click
6: 164v, click
7: 0v, no click
8: 1v, no click

V2:
PIN:
1: 160v, click and slightly noise
2: 0v, no click
3: 1v, no click
6: 198v, click
7: 17v, click
8: 45v, click

V3:
PIN:
1: 0v of course
3: 339v, click
4: 313, louder click
5: 0v, no click
6: 0v, no click
8: 19v, no click

V4:
PIN:
3: 339v, no click
4: 313, louder click
5: 0v, no click
6: 0v, no click
8: 19v, no click

A: 344v, quiet click
B: 313v, click
C: 243v, click

so, what is your diagnosis guys??it seems to me a bit strange not having voltage at pins 5,6 at 6V6s,isn't it?

[ben85]

Also, i found out that every of the four 0.1 μF capacitors they have 0v on the one side,even they have much voltage on their other side.is it reasonable??

[paddy]

V1 pins 3 and 8 should have the same voltage as they are tied to the
same cathode resistor.
The .01 caps are o.k. They should have high volts on one side and 0 volts
on the other. Find out why V1 pin 8 is 0V. Maybe bad joint/miswired.

Cheers,
Paddy

[ben85]

ok,sorry,this was a typo,i'll fix it now

[martin manning]

All of those voltages look good now. That says that you have got the current flowing through the tubes as it should be. If you still have no sound the signal is getting dropped somewhere. This would be a good point to try tracing a signal through from the input .

[ben85]

could you tell me how to do this martin, please?

[martin manning]

Basically there are two ways to go about it.

One is to put an AC signal in at the input, which can be a steady tone or the output of a music player, and then using a probe made from a capacitor and a cable plugged into another amp, probe the circiut to listen for the signal, moving from the input jack tip lug to the V1a grid, to the V1a plate, etc. until you find a place where the signal is lost. Then you know where to look for a bad connection or wiring error.

The other way is to use the same type of probe, this time connected to the signal source, to inject an AC signal at various points and listen for it at the speaker output. For this you would begin at the power tube grids and move back toward the input until you find a place where the injected signal stops appearing at the speaker. This is basically what you are doing when you listen for the pop or click when you apply your multimeter probe to measure a voltage.

Good info here (earlier in this thread): https://tubeamparchive.com/viewtopic.ph ... 700#240700

[ben85]

thank you very much,i'm gonna try to do this!

[martin manning]

The signal probe can be simple, like this, and the capacitor value is not critical, 0.02uF-0.1uF.

[Reeltarded]

The clip makes it so much more simple to eat rice with as well.

[ben85]

haha,well double-purpose tool,it worthed troubleshooting,i learn many different things!haha

thank you!

[ben85]

so,the resistors are not necessary for this tool?only a cap?

[alvarezh]

"The signal probe can be simple, like this, and the capacitor value is not critical, 0.02uF-0.1uF."

Yes…..But it's voltage rating is. Ben, follow the instructions that states 600 volts dc rating on the capacitor.

Martin, I have noticed before that the OP sometimes has problems understanding instructions (and basic electronics). He's going to be probing on high voltage points, it's important we keep him safe!

All the best.

[ben85]

yeah,but i'm talking about the resistors showed in this link:

http://www.musicfromouterspace.com/anal ... racer.html

what about them?thanks for concerning anyway!

[martin manning]

Yes, good point Horacio.

One other caution is that if this probe is placed on a tube plate (like pin 3 or pin 8 of a preamp tube), a high AC voltage can appear on the cable, high enough to deliver a painful shock or damage the input of a solid state amp. The design linked above has a 10:1 divider built in, which would make it safer, and yes you can use a cap with a lower voltage rating.