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loosecannon · #31 07-02-2009, 11:24 PM

either one will be the same.

those two transistors are basically identical for our purposes.

also remember that you have to quadruple your power output to gain 1 S-unit on someones receiver.

that should tell you how much trouble you should go to for a given power increase.
LC

Oldtimer · #32 07-28-2009, 08:40 AM

Moleculo how are ya?
What is the easiest way to remove a turn on the coil?
Thanks.

moleculo · #33 07-28-2009, 12:53 PM

You have to desolder the coil from the board - remove it. Then you can just unwind one coil off of the can, bend the wire back into original form, and replace it, trimming the excess when done. Remember that the coil wire is coated, so you have to scrape off the coating where you will solder it back on the board. Do that before inserting the coil back into the board.

Oldtimer · #34 07-28-2009, 04:32 PM

Thanks Moleculo.
It worked great.
My Cobra 25 ltd has the stock final (2078) in it yet.
It dk's 2 and swings to 20.
If I put a 1969 final in would I see much difference or ain't it worth the time.
Thanks again.

moleculo · #35 07-28-2009, 05:55 PM

You can get the same results from a 25, but you'll have to cross reference the component numbers for the 29 against the schematic for the 25. I don't remember what they are, although I've done it before. Whether or not that's worth it to you is up to you

jazzsinger · #36 07-31-2009, 12:38 PM

Quote:

Originally Posted by OBJ1946

Me again- go to Grandata Online -they have 14 available as of 30/04/2009 20:40 GMT...At the fantastic price of £1.60...which I think is around $2.30 ? + post & packing....does'nt mention posting to the states...if you have any trouble getting these RF Output transistors either over there or here in the UK let me know and I could send for them here and post them on to you Guys over there in the good old US of A...Noooo problem, just give me a nod...Dave ( Near Manchester,England)

its highly unlikely they are genuine mitsubishi 2sc1969 at that price.genuine ones go for between £10-£15,about 18-30 dollars each.

coyote · #37 08-01-2009, 07:57 PM

Moleculo, i want to try your 29 mod w/ 1969 final. i am confused as to what a .2 monolythic is. i think i understand all the other parts mentioned and the procedure was well described. i need only to locate some authentic 1969 and 2166 transistors. there is a ham fest in sept. by me, maybe i can find them there. i am just a little confused with the .2 monolythic part. any help with this would be greatly appreciated.
coyote, 620 in the poconos, pa.

loosecannon · #38 08-01-2009, 11:12 PM

a monolythic cap is a type of ceramic capacitor.

it has to do with the way the capacitor is made.

they look similar to tantalum capacitors in shape.

look at an electronics parts store in the ceramic capacitors section, you should find them there.

good luck,
LC

rockman · #39 09-23-2009, 08:40 PM

I just did this mod to an old 29 ltd. A friend game me an IRF530 he said it was the same as the IRF520, and I used the home made biasing circuit instead of the 1230. The radio works, but I am keying like 3 watts and swinging maybe 10 if that. Seems somthing is wrong. Any ideas, is the 530 not the same thing? Any help greatly appreciated.

MisterFatty · #40 09-23-2009, 08:57 PM

Quote:

Originally Posted by rockman

I just did this mod to an old 29 ltd. A friend game me an IRF530 he said it was the same as the IRF520, and I used the home made biasing circuit instead of the 1230. The radio works, but I am keying like 3 watts and swinging maybe 10 if that. Seems somthing is wrong. Any ideas, is the 530 not the same thing? Any help greatly appreciated.

Guess the first question that comes to mind is what meter are you using for measurements?

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Cobra 29 High Power mod with 2sc1969 transistor