Eden wt 400 issues

[ibanez7]

Hi To all,
I'm having some problems with my eden wt400,the voltage readings on the tube are wrong,i get -7v on the heater which is wrong according to eden,I've checked almost everything I could think of,tried different tubes etc.any help would be greatly appreciated.
Thank You
Roger

[J M Fahey]

Hi Roger.
Ok, but, what *does* it do?
What made you open it?

[ibanez7]

Eden WT400

I'm getting no audio from input jack,but you can hear the audio on the speakers,I've tried different tubes,resoldered the preamp,power supply board,an amp board,I've got the schematic,if you would like to tak a look at it.

[J M Fahey]

I'm getting no audio from input jack,but you can hear the audio on the speakers

I'm very sorry but that phrase is contradictory.
Input jacks are to get sound in, not out.
And you say you hear your sound through the speakers. How does it get there ????
Please clarify.
I have the schematic open on another screen.

[ibanez7]

wt 400

well what i actually meant,was I pluged in a guitar cable on the input of the amplifier,to test,but its not working however I can hear the audio on the speakers if i raise the master volume etc,but just can get any sound from the inoput of the amp via guitar cable

[Enzo]

What DC voltage is across C35, the 1000uf cap? Now what AC voltage is across that cap?

What DC voltage is across the 12v zener D13?

[ibanez7]

wt 400

Hi there,do you mean with the meter black lead to ground and the positive lead on the cap?

[ibanez7]

wt 400

Hi there,do you mean with the meter black lead to ground and the positive lead on the cap?

[J M Fahey]

Hi ibanez.
Since the schematic is incomplete, we don't *really* know how this heater power supply is grounded, so Enzo suggests a failproof measurement: "across" means black to negative, red to positive, on the cap legs/pads themselves.
Same with the zener.

[ibanez7]

wt400

Hi there the voltage across d13 is -9.2mv,for c35 its -18v and 3.8vAC

[Enzo]

Yes, across means end to end, like how far is it across that bridge?

SO you have very low voltage across that 12v zener. SO either the zener has collapsed, or D12 above it has failed, possibly C39 has failed.

The voltage across C35 sounds reasonable.

[ibanez7]

wt 400

Hi enzo thanks for the advise,I've replaced that c39,checked the zener diodes,they all check out ok out of circuit.

[Jazz P Bass]

http://music-electronics-forum.com/t16561/
Check the fuse holder position!

[ibanez7]

wt 400

tried that initially,its installed in the correct position set for 110v

[J M Fahey]

,I've replaced that c39,checked the zener diodes,they all check out ok out of circuit.

OK, ok, fine, but what are the voltages now?
Specifically: this is a 12V DC negative supply feeding your 12AX7 filament.
Parts are right? Good, it does not mean it works.
Please check the following voltages, 20V DC scale, negative probe to ground:
> "-" leg of C35
> "-" leg of C39
> legs 4/9/5 of 12AX7 with and without tube in the socket.
> Emitter/base/collector of Q12 (Tip 32)
I am not only testing "parts" but cracked tracks or solder or lack/failure of voltage feeding this regulator or defective 12AX7 socket.
Thanks.