Here's the Q voltages for my Whisker.

Started by JimRayden, August 30, 2005, 08:54:47 AM

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JimRayden

Q1
E - 0.02
B - 0.6
C - 3.65

Q2
E - 0
B - 0.6
C - 1.5

Q3
E - 0.02
B - 0.6
C - 3.6

first I plug it in - seems to work nice. Just after a few seconds of working, it fades out and makes almost no sound.

Also, my Q2 is actually two 2N5088's.

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Jimbo

JimRayden

Correction for the Darlington voltages:

Q2:
E - 0V
B - 0.06V
C - bananaz

My 2x2N5088 Darlington seems to be misfunctioning. it's kinda impossible to measure the collector since it's running from 8.8 to 3.4 to 1.5 back and forth.

Oh, and the schemo is here. :)
http://www.runoffgroove.com/whisker.html

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Jimbo

JimRayden

Here's a bump for those who don't read the second page. :)

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Jimbo

petemoore

Ya hook a screwdriver to your thumb and touch 'out'
 If the pots up at all you should hear humbuzz through the amp
 Turn the pot up to where its up where it don't hurt
 touch toward SP and circuit on the other potlug,Try the Collector/outcap if the last stage is biased at ll  youull hear buzz there too, same as at "out'
Try the Collector/outcap, if the buzz made it this far try the Base of last stage, the buzz should be a little louder/distorted since it's a biased BMP gain stage. Loss of signal from C to B in a gain stage indicates mostly misbias.
 You could audio probe from the input, I find it's pretty fast finding with the thumbuzz technique, I don't have an AP. Dont try this technique with HV in amps or anything.
Convention creates following, following creates convention.

petemoore

Scratch all that for now, it looks like all the transistors are misbiased.
 The diode replaces a large resistor from C/B type biasing for that one, not sure what the voltages should really be there.
 Pretty sure all three stages are gain stages with headroom enough to substantially gain, this would mean the emitters are a small R Value and hence, small voltage from ground [right around .9 'something or less], base one diode drop above that .6v or so, and the collector around what..4.5v?
 There's something like miswire, extra connection or...you Are putting 100's in and not 100k's..I've done that plenty of times.
 you socket?. pull the Q's and measure over the 10k's in the circuit....no socket's measure 'em anyway....do same for the 100k's and the 100's
 470k color codes to YPY, might as well measure them too.
Convention creates following, following creates convention.

JimRayden

All the resistors seem to be intact. I'm thinking that it's caused by a cap because the voltage is changing slowly, like 0.1V per sec. Could that be the case?


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Jimbo