diyAudio

diyAudio (http://www.diyaudio.com/forums/)
-   Pass Labs (http://www.diyaudio.com/forums/pass-labs/)
-   -   FET10e Channel Noise (http://www.diyaudio.com/forums/pass-labs/175250-fet10e-channel-noise.html)

sparky54481 12th October 2010 05:03 PM

FET10e Channel Noise
 
Hello all! New user looking for assistance troubleshooting a fet10e. Recently right channel began "making noise". Narrowed down with O-scope to sinusiodal inputs resulting in 1/2 wave rectified output. Further checking, it appears the output transistors Q8, Q9 are not biased on (comp1 voltage is ~0.4v, while on good channel it is around 0.88v). I suspect component hfe drift, possbily requiring adjustment of pot or component replacement.

Anyone have any suggestions? Thx.

Zen Mod 12th October 2010 06:54 PM

1 Attachment(s)
Q8 and Q9 ?

on which schematic ?

this one ?

sparky54481 12th October 2010 10:23 PM

FET10e Channel Noise
 
Yes, thats the one! S5541098.

Zen Mod 12th October 2010 10:48 PM

can you use that pic and write measured voltages in few critical places

the more the merrier

sparky54481 13th October 2010 11:32 PM

Troubleshoot FET10e
 
1 Attachment(s)
OK, much easier for me to make a little spreadsheet. See if you see what I am thinking - Q7...


All times are GMT. The time now is 06:36 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio


Content Relevant URLs by vBSEO 3.3.2