BC10B & BC108A hfe problems

[formerMember1]

Hello,

I do know the pinout of these transistors, i used the search function  :wink:

But when i test the hfe of them in my DMM, the hfe shows up between 001 to 006 for the transistors. What does that mean?

They are NPN, and no matter what, I get those readings, When i put them in any other way the DMM turns off, indicating wrong pinout.  

Anybody have this problem? I have 5  of each transistor type and they all do this.  They are for a  Vox Wah clone. :wink:

tank you :lol:

[Fret Wire]

Battery good in the DMM?
DMM set on hfe, not diode?
Do any other trannys test normally on the DMM?

Check manual for DMM, in the specs it will tell what current the hfe test is. Most test at 10ma.

Ok, you know your tranny pinout. Are you sure of the DMM socket pinout? Some have sockets for PNP and NPN, and four sockets per each for different pinouts. Those readings sure sound like the pinout is wrong. Usually the tab is the emitter on BC's.

I have one DMM that the tranny socket crapped out after about 15 tranny tests. Bizzare readings. Do you know anyone else who has a DMM with a HFE socket so you can check against yours?

[formerMember1]

battery is fine, Other trannys test fine, They are labelings on the DMM to show pinout, I do have the pinout correct on the transistors too.  It is set to hfe.  I don't know what could be doing it. :?


I got the trannys off Banzai.  I'll check the manual again, but other trannys test fine and show the correct HFE readings.

thanks for the help

[Fret Wire]

Being si trannys, I'd hate to think they're all duds. How do the leads look? Are they shiny or dull. Give em' a quick cleaning with sandpaper and test again. If that's a no go, then use the DMM to test if they are even good.

[formerMember1]

yeah man, that did the trick i sanded the leads a little till they were shiny and it worked, and i got the right readings.  I would have never thought it was that, I didn't think they could all be duds either

thanks again,
I might make my  own hfe tester though, cuz the leads are so short on those trannys that it is hard to stick them in that far in the tester socket to get a accurate reading, it really requires some excessive force to get the leads in their.
I read something on this forum i am gonna try, :wink:

[Fret Wire]

What did their hfe test at btw?

[formerMember1]

i only tested a few, really quick
I cant remember which type but they measured around 300hfe  I think one measured 168, but not sure,

I have 5 bc109b and 5 bc108a, i don't have any time now, but tomorrow, i will post to this thread what each one tested out as.  then when i get my other parts i will post on what "pair i liked the best in my wah. :wink:

[formerMember1]

Here is the different hfe tested.


BC108A:                
182                      
180                      
173                      
170                      
176                      

BC109B:
333
325
339
301
326

I was hoping for some of the BC109B's to test around 400 like phillips at fuzzcentral, but i guess i should have ordered some BC109C's also then, :roll:

Oh well, I think they should still sound good in my Vox Clyde McCoy wah clone anyway. :wink:

I'll post up in a few weeks of what tranny pair i thought sounded the best.
later gators

[Fret Wire]

I'd use the 109's for the wah, and save the 108's for FF's.