Help troubleshoot mosfet install in a Uniden 78/Cobra 29?

[Robb]

Well, if it doesn't already have the cap/resistor mod, then there are only a couple of things left to check.

The first to to see if ther is enough capacitance on the output for the MOSFET install.

BTW - did you peak the TX coils yet?

 

[ScurvyPete]

Other than trying to tweak L14 and subsequently breaking the slug and getting it stuck in the tank, no.
My thinking was that I would wait for that until after I had got this mosfet install sorted out, but I guess I can try it now and see what happens.
Any other thoughts/things you'd do differently?

 

[Robb]

http://www.cbtricks.com/miscellaneous/fet_papers/ekl/graphics/erf2030_cobra_29_mod.jpg

 

[David Waits]

That's a good way to Mod.kit the 25/66 and the 76/29 radios. I use a 470uf at 25V and usually a 30 ohm, 1/4watt resister. gives a 1-1/2watt DK and a ton of superfast modulation. Just breath hard into the mic and it slams a modulation needle. Drive low DK boxes like no tomorrow. Don't forget to remove JP36 and clean the holes.

 

[2FB327]

Pete, sorry I was away, I didn't mean to bad mouth any meter, I just wanted to make sure your comparison was the same, I have a dosy, a bird and a few others.
When I first started doing this mod, I couldn't get the dosy to read more than 25, when I hooked it to my bird and hooked it to a friends bird it read 38. Come to find out that many people feel that most meters do not have the circuitry to read true pep.
My suggestion is ditch the swing mod, install a piece of solid copper wire in jp36, look to see if R55,R56 is missing or clipped, tune and see if you pep increases.
What I meant buy the companion part is that I purchased 3 of them and tried three different radios and never could get the bird above 25, pulled out my three remaining hairs and started over from scratch.
What I did find is that if I ran a resistor from the positive side of c116 to the gate I could control the "bias to the gate"
Hope this helps

 

[ScurvyPete]

http://www.cbtricks.com/miscellaneous/fet_papers/ekl/graphics/erf2030_cobra_29_mod.jpg

Robb, these were the instructions I used to perform the install. The only things I did differently were that I didn't put the cap on the back of C59 and I didn't remove the tuning slug at L14 (I'm still trying to figure out how I'm gonna get that sucker out, or at least move).

Pete, sorry I was away, I didn't mean to bad mouth any meter, I just wanted to make sure your comparison was the same, I have a dosy, a bird and a few others.
When I first started doing this mod, I couldn't get the dosy to read more than 25, when I hooked it to my bird and hooked it to a friends bird it read 38. Come to find out that many people feel that most meters do not have the circuitry to read true pep.

No offense was taken. It doesn't really matter to me what the numbers are, so much as that they are improved over what I had. I would be tickled to death to hit 25 on my Dosy right now, because I'm only seeing 7-8 now.

My suggestion is ditch the swing mod, install a piece of solid copper wire in jp36, look to see if R55,R56 is missing or clipped, tune and see if you pep increases.

I removed R55 and R56 as part of the mosfet mod. R56 was replaced with the EN-1230 companion part, and R55 was left open. I haven't touched JP36 yet, so as far as I know (because I haven't looked yet), it should still be an intact jumper.

What I meant buy the companion part is that I purchased 3 of them and tried three different radios and never could get the bird above 25, pulled out my three remaining hairs and started over from scratch.
What I did find is that if I ran a resistor from the positive side of c116 to the gate I could control the "bias to the gate"
Hope this helps

So, did you remove the companion part and replace it with something else or what? I kind of understand what you're telling me here, but I'm having a hard time wrapping my mind around the whole thing

 

[Handy Andy]

Another Good Thread...

Bump

Hope the Radios' "doin' what It Should!"​

 

[1iwilly]

for L14 unsolder it from the radio then take the right size screwdriver working it up slowly until it's out or from the bottom then put it back on the radio with a better slug
hope this helps

Robb, these were the instructions I used to perform the install. The only things I did differently were that I didn't put the cap on the back of C59 and I didn't remove the tuning slug at L14 (I'm still trying to figure out how I'm gonna get that sucker out, or at least move).