The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

my euro3900 had a 2sc1969 final that went poop.... i was wondering if anyone could help with info to convert it to an irf520.

it has two trannys mounted to the rear heatsink, one was a 1969 and....well i don't remember what the other was, so i'm not sure if it has dual or single finals. each transistor has a bias adjustment pot.

the reason i'm confused about it being dual or single final is because it also has a 2sc2314 (I think) driver installed on the PCB just in front of the rear mounted trannys.

so, how could i stick a 520 in there

if anyone needs the PCB number, I'll crack the case back open and find it. thanks.

When ask for any help it is always best to give the PCB number.

If the radio is working ok, I would stay with the bipolar transistors as long as you can, it makes no sense just changing them just to gain a few extra watts.

I may find the info you need is on
http://www.cbtricks.com/miscellaneous/f ... /index.htm

Good advice keep with stock tran as long as you can.

James.

well, thing is... the tranny is already toast. I would really like to find a 1969 replacement, but aren't they discontinued? If there are any left out there, does anyone know where I could find a REAL one? Or at least a suitable replacement?

I really don't want to hack up this radio!

They are discontinued, and, if you do find them, they are quite expensive, I would not hesitate going with a mosfet at this time, they work really well.

I found this on the net: Workman 1969X CB20W 2SC1969 Replacement..... It says that it is meant to be a drop in replacement for the 1969 and will work fine with a properly adjusted bias voltage.

I also found some genuine 2sc2312's for 10 bucks.

I'm just wondering if anyone has tried any of these and if they will work. I have been having the worse kind of luck finding a genuine 2sc1969.

Thanks...

CB20Ws are garbage, I would take the 2312's.

Thanks guys for all the help. I think I'll try the 2312's out.

All new Superstar 3900 radios(with the blue s meter and channel readout) are using 2 x irf520 mosfets for the output. My 3900 does 10 watts am/fm and 20 pep on ssb. Will these handle ok at these ratings? I always wondered why Mitsubishi discontinued the good old 2sc1969. They were very robust.

Everybody keeps saying the 2sc1969 is hard to find and expensive. buy them here.http://www.rfparts.com/transistors_2SC. ... 9115918011

If they are out of stock I have some I will sell for 10 bucks.