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

I bought the radio with issues. I had low TX , 1-2 watts AM. I swapped the AM regulator to an 2SB817, still same problem. I adjusted the PLL via L17 and voila I got 25-30 watts TX. 1 week later I noticed that when I turn the power on I get little RX then a minute or so later it would kick in and normal RX. I also notice soon after I turn the radio on I would be able to get 25-30, out of no where I drop down to 10 watts TX.
My question is the PLL losing the voltage somehow and I'm out of "lock"? As Doc Electronics is the man for 2510's , where is the shop to send my 2950 to?Thanks

If the pll was going out of lock..you would have no rx and no tx at
all..I would be looking in the area of the voltage regulator chip..
I believe it is ic-4 in this radio,not certain on that number however.
But it should be the first chip on the right side rail of radio.
It could also be a shunt component off this chip.Or a poor solder
connection in this area..Does the face plate L.E.D.s go dim when
this happens????

I have no dimming . however I have noticed that the area on the middle of the radio near the voltage regulator gets real warm on the chassis. I made a homebrew rf probe but I can't get it to work right so really I'm shooting in the dark. I have a parts radio to pull from but not to many IC chips to pull from. Thanks

I would suggest starting taking some voltage readings and relay
them to us...Take readings while the radio is in fault mode.
And we can compare them with our voltage chart..Like i said start
by giving your readings around the voltage regulator chip..And
B.T.W. I wouldnt worry about the Am Mod Amp getting warm, they
will do that. Just as long as it doesnt get real hot.

After taking a look at schematic..IC-4 is the 5 volt regulator.
And the 8 volt regulators are IC-6 AND IC-15 these are along
the right chassis rail,the 2 ics closes to the front of radio.
They should be 7808s and the 5 volt reg. should be a 7805.

Try setting up the PLL section as per http://www.cbtricks.com/radios/rci/rci_ ... ll_adj.htm

James.

31:Can you check your 2SC2312 Final transistors?

It is because this is a very common problem in this type of radio when you have one bad or leaked of the 2SC2312 Final transistors!!!!