Leslie 910 Solid State PS - Switching PNP?

[jdak907]

Hello all,

I need some help. I am working on a Leslie 910 rotating speaker cabinet which has a 70's era solid state amplifier in it.
Q33 - a TZ-525 PNP transistor had the leads twisted off some how and I need to find a replacement. I've tried googling it many different ways and can't seem to find any reference to an equal.
I am not sure but I believe this is used in a switching application. Can anyone help? See attached, sorry no schematic just a board layout available.

Thanks,
Jeff

[coromonadalix]

similar model
http://www.organplus.com/technique/leslie/lesli%20925sm.pdf

I would try any pnp transistor at 100v 1 amp current     

like :   2N2904  2N2904A  2N2905  2N2905A  in to39 casing  with an small heatsink too

but yours is an to92 casing with an small heatsink on it

like an 2n3906 or bc557 at 200ma   but it maybe not enough in current   an 2N2907  would be more powerful at 600ma  ...

[Rog520]

Check this place out. They have a PNP transistor with a part # 033571 listed:

http://www.organservicecompany.com/parts.html

[coromonadalix]

hum  not sure about this one, but it cost 5 box   to try it

[floobydust]

I have that style of transistor, it's TO-92HS or a TO-92 with a flag heatsink good for 1W.
I would put in a TO-220 part, it's closest.

Q32 NPN 2N4425 40V 0.5A 0.9W hFE 180-540
Q33 PNP Sprague TZ525

It's a two-transistor limiter circuit, controlled from the console Rev/Aux switch P1-4 and Q33/Q32 turn on the LDR light bulb M1 to limit volume.

I would use: TIP41C, TIP42C 100V 6A 2W hFE=100. hFE is lower but the circuit has feedback to accommodate.
TO-126 parts are OK too like BD140/BD139

I could not find specs on the driven light bulb, it seems to get up to 15V off the 33V rail, and is mated with assembly LDR 030379 on the crossover board.

[jdak907]

I have that style of transistor, it's TO-92HS or a TO-92 with a flag heatsink good for 1W.
I would put in a TO-220 part, it's closest.

Q32 NPN 2N4425 40V 0.5A 0.9W hFE 180-540
Q33 PNP Sprague TZ525

It's a two-transistor limiter circuit, controlled from the console Rev/Aux switch P1-4 and Q33/Q32 turn on the LDR light bulb M1 to limit volume.

I would use: TIP41C, TIP42C 100V 6A 2W hFE=100. hFE is lower but the circuit has feedback to accommodate.
TO-126 parts are OK too like BD140/BD139

I could not find specs on the driven light bulb, it seems to get up to 15V off the 33V rail, and is mated with assembly LDR 030379 on the crossover board.

Hey thanks a bunch! I used the TIP42C and it seems to be working. I do have some crackling at higher volumes but still need to clean pots and verify passive component health.

Jeff

[floobydust]

That board looks very good 

I repaired two Leslies, buzzing speaker- was dead bugs (moth) fell in the horn,  landing on the driver diaphragm and the second had metal shavings in the driver magnet-gap.
Pulled the voice coil out and used masking tape to clean up the metal chips, they stick to the tape. Have to use plastic sticks.