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

Rick, I just wanted to update this thread. Again, thanks for your help and patience. I decided it was time to dig into this thing again after reading a message on another forum. The symptom was the radio wouldn't go into receive mode which I felt was more my problem than not being able to hear. In t...

Item F is an E.F. Johnson Messenger III... says so right on the front of it.

Isn't there a mod around somewhere for the HR2510/HTX100 that replaces the 477 to 455 mod with a 1446? The IRF520s are not a pin for pin replacement for the 477 and you wind up with them "cross-legged".

Rick, I want to thank you for your help and patience, I think I am going to put the covers back on and set the whole mess aside for a while. I've been fooling with this one long enough and it has just worn me down. Besides, it is taking up too much space on the bench. One day, soon I hope, I will pu...

After think about the fault a bit more. I think you will find that L8 is open circuit, as you say there is 3.4 volts on the anode of D19, this should be zero volts. I changed out d21 and 22, and rechecked the voltage on the others. Here is what I have d20 c=2 a=0 d18 c=2.7 a=3.4 d19 c=2v a=0. I DID...

Sorry, I thought the subject naturally followed the thread. I'll try 21 and 22 and then recheck the voltages on 18, 19 and 20 since I screwed that up the first time and may have even confused myself. The radio is on frequency when in receive. I've done the PLL alignment (I don't have a scope though)...

Taking d18 out of circuit DOES seem to help, the static level is higher and reception from a nearby radio is louder, although I can't don't receive anything off of the antenna. The junction of R75/76 runs 3.6v with RFGain all of the way down to 0 all of the way up. IC15 shows 1-13.9 2-0v 3-8v.

Thanks Rick, you are right about me having d18 and 19 mixed up. The voltages are swapped for 18 and 19. D19 is c=2.7 a=3.4 and D18 c=1.6 a=.1... sorry about that.

Q37 is good on voltage, I will get back to you on R75 & 76 and IC15, although I am pretty sure IC15 and IC6 tested in spec.

A few parts to check. R76 R78 D20, D21, and D22 What is the voltage at each side of D18, D19, and D20? Checked 'em out. R76 reads 1.4K, R78 reads 2.1K. D20, 21, 22 are all good, voltages D18 c=2.7v a=3.4v (I think I got those right, D18 is SMT on the back side) D19 c=1.6v a=.1 D20 c=2.0 a=2.7. Than...

I was given an RCI 2990 with an EPT295013Z board. When I got this thing it was a MESS. Physically the outside was in great shape, and the display worked... a good start. Inside wasn't so good. It looked like the previous owner had tried to hot rod it in every way possible. The most classic was the M...

http://www.geocities.com/n2uhc_2/10m_dipole.html

I keep wanting to try this one myself, it looks like a fun easy project. It is for 10 meters, but can be easily modified for 11 meters. Good Luck!!