# Woodpecker transistor equivalent?



## BurntFingers (Nov 7, 2019)

I cannot find a pf5102 anywhere without insane shipping (I'm in new Zealand). Is there an equivalent that would work in it's place, something more readily available?

Also, I've got the on\off\on switch here from tayda. Unlike most of my on\on toggles where The switch stays out at either end, this on-off-on instantly springs back to the off position (in the center) when pushed. Is that normal?


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## K Pedals (Nov 7, 2019)

BurntFingers said:


> I cannot find a pf5102 anywhere without insane shipping (I'm in new Zealand). Is there an equivalent that would work in it's place, something more readily available?
> 
> Also, I've got the on\off\on switch here from tayda. Unlike most of my on\on toggles where The switch stays out at either end, this on-off-on instantly springs back to the off position (in the center) when pushed. Is that normal?


The switch you have is momentary... you ordered the wrong one... it’s happened to me before...


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## BurntFingers (Nov 7, 2019)

Shit. So I need to reorder the other kind. 

One of these bad boys?









						Switch Toggle ON-OFF-ON, SP/DT 3 Pin Panel Mount 250V 3 Amp,13mm x 7.5mm
					

SW0041




					www.surplustronics.co.nz


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## Chuck D. Bones (Nov 7, 2019)

It's normal for a momentary action switch, but not what you want for the Woodpecker.  As far as the JFET goes, you could probably get away with any N-channel JFET, but you will probably need to adjust the value of *R3*. You want Q1's drain to be somewhere in the vicinity of 5 or 6V. What JFETs do you have?


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## Chuck D. Bones (Nov 7, 2019)

BurntFingers said:


> Shit. So I need to reorder the other kind.
> 
> One of these bad boys?
> 
> ...



Yes, that will work.  Where did you manage to find a 2N6027?


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## BurntFingers (Nov 7, 2019)

Chuck D. Bones said:


> Yes, that will work.  Where did you manage to find a 2N6027?



Jaycar. Sort of like the RadioShack in these parts. $2.40.


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## BurntFingers (Nov 7, 2019)

Chuck D. Bones said:


> It's normal for a momentary action switch, but not what you want for the Woodpecker.  As far as the JFET goes, you could probably get away with any N-channel JFET, but you will probably need to adjust the value of *R3*. You want Q1's drain to be somewhere in the vicinity of 5 or 6V. What JFETs do you have?


Ive got some 2n5089, L78 L05, 2n5458, 2n2222a, and some left over random Qs from earlier builds like mpsa18, 13, but if these are jfets I honestly don't know. Apologies if this is zero help.


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## Nostradoomus (Nov 7, 2019)

The 2n5458 is what you’ll want to try.


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## Chuck D. Bones (Nov 7, 2019)

Good news: The 2N5458 has the same pinout as PF5102.  Bad news: The 2N5458 has a large range for Vp, so the ones you have may or may not work.  How many do you have and do you have a DMM?  We could try pre-screening them before you solder one into the board.


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## BurntFingers (Nov 7, 2019)

I think I have 2, and yep got a dmm.


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## Chuck D. Bones (Nov 7, 2019)

To measure Vp, connect the + lead of your meter to the JFET's S lead. Connect the - lead of your meter to the G lead.  Set the meter for the 2V scale.  Connect the - side of a 9V battery or power source to the G lead.  Connect the + side of a 9V battery or power source to the D lead.  The meter will read Vp.  If the meter reads overrange, switch to the 20V scale.  Ideally, you're looking for Vp under 2V.


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## BurntFingers (Nov 7, 2019)

Sounds fun. I may have others in another bag. I will have a look and report.

Thank you for the help thus far.


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## BurntFingers (Nov 7, 2019)

Chuck D. Bones said:


> To measure Vp, connect the + lead of your meter to the JFET's S lead. Connect the - lead of your meter to the G lead.  Set the meter for the 2V scale.  Connect the - side of a 9V battery or power source to the G lead.  Connect the + side of a 9V battery or power source to the D lead.  The meter will read Vp.  If the meter reads overrange, switch to the 20V scale.  Ideally, you're looking for Vp under 2V.



I've got a 2n7000, 2n3904, and a bunch of bc549s. I don't think any of those is a substitute, maybe the 2n7000 in a pinch but I think that'd be a mosfet, and not a jfet.


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