05-25-2009, 10:16 PM
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Join Date: Dec 2008
Location: Silicon Valley CA, Storm Lake IA
The transistor replacement is a 2SC2999; but there is a better version of it. The Sanyo 2SC2999 "E" is a bit more costly but is the 'cleanest of the clean' amping transistor. They can be had from B&D Enterprises: B&D Enterprises: Part #2SC2999E-SPA
Two of the diodes are part of the detection circuit, and can make it a bit too sensitive - in the sense that they can even overload the receive. The other two diodes designated are used in the noise blanketer circuit. Cobra 29's only need 3; most other radios need 4. Truth is, the transistors are the parts responsible for knocking down the noise and improve the signal level.
Some radios often will have a better receive if two 2SC2999E's are used - one for the first IF stage amping and the other for the SSB
receive amping. Their advantage in use is to give the receive more signal gain before noise. The diodes aren't always the most popular mod, but the transistors are always welcome to any radio - IMO. Personally. I would do the diodes too - I have done this to all of my radios when adding the transistors. After these mods, realignment of the radio isn't necessary - unless it needed it to begin with. These mods cannot right an out of tune radio; they just clean up its act favorably...
I've done a couple of Cobra 29's and 148's with really phenomenal results. Some think these mods are petty; I think these mods are useful and quite noticeable. I don't know what kind of IF transistors are in my Galaxy DX 99V. But if they are substandard and be cross exchanged, I will put the Sanyo 2SC2999E's in it - too. The receive in the Galaxy is already very nice, but it will still work better with the transistor mod.
BASE: Kenwood TS-2000, GAP Titan DX, Diamond X50A, Sirio SY27-4, and IMAX 2000.
MOBILE: Galaxy DX99V w/RF Limited CR-577 mic, Sirio Z-180. Yaesu FT-8800R & Diamond NR-770.
Last edited by Robb; 05-25-2009 at 10:47 PM.