EURO 3900 IRF520 conversion

Discussions on CB Radio Modifications
Post Reply
User avatar
Dino_24
Dead Key
Dead Key
Posts: 29
Joined: Monday 10th Nov 2008, 15:28
Location: Tennessee
Contact:

EURO 3900 IRF520 conversion

Post by Dino_24 »

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 :?:
Cobra 29/NW/ST
Cobra 29 LTD
Realistic trc-52
Realistic trc-217
User avatar
Dino_24
Dead Key
Dead Key
Posts: 29
Joined: Monday 10th Nov 2008, 15:28
Location: Tennessee
Contact:

EURO 3900 IRF520 conversion

Post by Dino_24 »

if anyone needs the PCB number, I'll crack the case back open and find it. thanks.
Cobra 29/NW/ST
Cobra 29 LTD
Realistic trc-52
Realistic trc-217
User avatar
Rick
Technical Helper
Technical Helper
Posts: 1041
Joined: Sunday 4th Jun 2006, 12:52
Location: UK

EURO 3900 IRF520 conversion

Post by Rick »

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
Rick.
James Unit 198
Frequent Keyer
Frequent Keyer
Posts: 63
Joined: Friday 4th Aug 2006, 22:34
Location: London UK

EURO 3900 IRF520 conversion

Post by James Unit 198 »

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

James.
User avatar
Dino_24
Dead Key
Dead Key
Posts: 29
Joined: Monday 10th Nov 2008, 15:28
Location: Tennessee
Contact:

EURO 3900 IRF520 conversion

Post by Dino_24 »

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!
Cobra 29/NW/ST
Cobra 29 LTD
Realistic trc-52
Realistic trc-217
timrim
Heavy User
Heavy User
Posts: 259
Joined: Thursday 29th May 2008, 10:11
Location: Ohio

EURO 3900 IRF520 conversion

Post by timrim »

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.
User avatar
Dino_24
Dead Key
Dead Key
Posts: 29
Joined: Monday 10th Nov 2008, 15:28
Location: Tennessee
Contact:

EURO 3900 IRF520 conversion

Post by Dino_24 »

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...
Cobra 29/NW/ST
Cobra 29 LTD
Realistic trc-52
Realistic trc-217
timrim
Heavy User
Heavy User
Posts: 259
Joined: Thursday 29th May 2008, 10:11
Location: Ohio

EURO 3900 IRF520 conversion

Post by timrim »

CB20Ws are garbage, I would take the 2312's.
User avatar
Dino_24
Dead Key
Dead Key
Posts: 29
Joined: Monday 10th Nov 2008, 15:28
Location: Tennessee
Contact:

EURO 3900 IRF520 conversion

Post by Dino_24 »

Thanks guys for all the help. I think I'll try the 2312's out.
Cobra 29/NW/ST
Cobra 29 LTD
Realistic trc-52
Realistic trc-217
Damselfly
Dead Key
Dead Key
Posts: 19
Joined: Friday 9th Jan 2009, 9:42
Location: Uk

EURO 3900 IRF520 conversion

Post by Damselfly »

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.
texan
Newbie
Newbie
Posts: 5
Joined: Tuesday 17th Mar 2009, 14:17
First Name: david
Location: albany ny

Re: EURO 3900 IRF520 conversion

Post by texan »

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.
Post Reply