[Argus25]

Originally Posted by Station X

Some OC170's only had three leads, but I've never been able to find data for them.

https://www.vintage-radio.net/forum/...ad.php?t=69688

I have the Philips data sheets, they are all 4 lead types, very detailed with circuit examples and graphs on OC169, OC170 and OC171 dated March 1960.

169 was for IF amp in AM & FM receivers ft 70MHz.

170 mixer osc SW and MW radios & 10.5MHz IF's, also ft 70MHz.

171 shown in the manual as 100MHz grounded base amplifier.

All characterized by very low collector-base capacitances and not requiring neutralization when used as IF amps.

Wonderful transistors, but unfortunately identical physical construction to AF114-118 and doomed to tin whisker death.

AF178's make great replacements for these too.