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Transistor with broken leg\lead

Started by dthurstan, August 05, 2013, 03:43:03 PM

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dthurstan

August 05, 2013, 03:43:03 PM
Hey

I snapped the leg of off 1 of my AC128s the other day that I'm using in a Mk II.   :'(

I did a quick search to see if there was any advice, general consensus was it's dead or to use it as a diode...

But I didn't give up, I soldered the leg back on as quick as I could, stuck it in the frezzer for a few seconds and it worked!!!

:icon_biggrin: :icon_biggrin: :icon_biggrin:



Soldering isn't great but it should hold. Measurements sometime before hfe 47, leakage 107mA. After hfe 51, leakage 118mA. I think I was very lucky that I didn't burn it, but I thought it was worth a try.

GibsonGM

#1
August 05, 2013, 06:39:16 PM
Nice!!
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tubegeek

#2
August 05, 2013, 07:24:13 PM
Quote from: dthurstan on August 05, 2013, 03:43:03 PM
But I didn't give up....

/cue stirring music

Way to go!
"The first four times, we figured it was an isolated incident." - Angry Pete

"(Chassis is not a magic garbage dump.)" - PRR

Thecomedian

#3
August 06, 2013, 12:20:15 AM
it's interesting to see how much leakage change also changed the hFE reading. Do you think the leakage/hFE ratio is constant? Might be a new way to calculate out leakage when determining true hFE.
If I can solve the problem for someone else, I've learned valuable skill and information that pays me back for helping someone else.

mistahead

#4
August 06, 2013, 12:24:54 AM
Need more data, but interesting, I think there is a third measurement still required...

I like data...

CodeMonk

#5
August 06, 2013, 01:40:47 AM
I've had to do that a time or three.
Here is an RCA 2N270 I got at an electronics surplus place.
Got them for a uhm...I forgot :) (Masetro FZ1?).
One of these days though.....


You did a nice job though.

dthurstan

#6
August 06, 2013, 01:38:06 PM
Quote from: Thecomedian on August 06, 2013, 12:20:15 AM
it's interesting to see how much leakage change also changed the hFE reading. Do you think the leakage/hFE ratio is constant? Might be a new way to calculate out leakage when determining true hFE.

I think the hfe and leakage values are really only a guide only. I've measured the same transistor a number of times and get slightly different results each time, they are so sensitive to temp and it has been hot and humid here in the uk recently, I may measure all my AC128s again. I measured it about 5 minutes after taking it out of the freezer and I got hfe 54 and leakage 137mA, so I thought I'd leave it for a day and check again.

I put it in the tonebender last night after posting and it works as before. As mistahead said more data required. Maybe I'll break a few more transistor legs and see if I get the same results  :icon_eek:
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