PC78LTW simple mod gone bad...

[Grinder74]

I found a mod years ago that changed the ch9 switch to go to 19. Since trying that, clipping a diode, it didn't work. I tried puting the diode back in but still has issues. The radio is repeating channels 1-9 at 11-19. Channel 10 and 20 is 40. 21 up is normal. Like I said, I did this years ago and put it away. Now being layed off and back to radio, I want to fix it. I don't have a straight AM radio running right now and would like some audio.

[Grinder74]

I finally got around to it last night. Replaced the diode, must have damaged it somehow. Dropped carrier down to a watt for the 2 X MRF455 I repaired, working great.

[TNT1450]

Glad you were able to fix it. I, too, have the habit of putting failed projects away for years and then finally coming back to them. Some I get to work, some I don't. The bad part about putting a project away and then pulling it back out after months or years is forgetting where you're at with it, what needs to be done to it and what goes where. I need to start writing notes and leaving them in the box with the project so I'll know where I'm at later on.

[TNT1450]

BTW, I don't know why they bother putting channel 9 switches in radios, I don't think anyone monitors it any more. Even REACT has gone to ham/MURS/FRS/GMRS and has largely left CB behind.

[Grinder74]

TNT, I think channel 9 was a REACT channel, some emergency channel that people monitored. Since I'm on furlough, I figured I should get some projects done. I tore a Turner plus 3 b apart to restore and put it back together, many years it sat in a box. Repaired a DOA amp and put a plug on a president mic for my HR2510. Channel up and down buttons are working. Next is either a power supply or go through my Teaberry "T" 40ch tuber, it's weak in transmit and receive.

[TNT1450]

From what I understand, and I could be mistaken on a lot of this, but I think REACT pushed the FCC for a rule change making channel 9 the official emergency/assistance channel back in the 70's. And they did monitor it for years until CB started to wane. But I read recently where REACT is more focused on public service and for the most part doesn't use CB any more. They certainly don't have the networks of channel 9 monitors they once did. But the rule about channel 9 being an emergency channel still remains even though you're more likely to get help using your cell phone than to find anyone on channel 9. In my area, CB is almost totally silent, and if you wanted to ragchew on channel 9 nobody would care or likely even know.

I have still been working all through this pandemic but lately have been working on CB projects of my own. Right now I'm working on my Cobra 29 10m CW QRP rig conversion. It's the old, very first, 23 channel Cobra 29 model. I've been swapping out the incandescent lamps with LED's, and just replaced the meter last night. The meter was stuck, which apparently was common in this model. Thankfully I salvaged numerous meters from other old junk CB's I've acquired through the years, and had one which fit perfectly.

I've also been researching information on how to convert 40 channel PLL radios. I'm thinking of putting this old Pace CB on 10 AM. From what I understand I'll need to build a 12 MHZ oscillator and feed that into the PLL to go up 2 MHZ.

[MDYoungblood]

Not to hijack this thread but check this out,
[Please login or register to view this link]
It hasn't been updated in 20 years but somebody is keeping the website active.

3's

Greg

[TNT1450]

Not to hijack this thread but check this out,
[Please login or register to view this link]
It hasn't been updated in 20 years but somebody is keeping the website active.

3's

Greg

Wow, they mention amateur radio packet and BBS's. That webpage is way overdue for an update.

I don't know if it's still up or not, but a few years ago the Dole-Kemp '96 website was still online.

[Grinder74]

The calendar link had 2009 dates.
This radio has a sticking meter so i'll have to tear it apart again...
The only issue i'm having is none of my power mics, other than the turner plus 2 will work on it. The turner plus 3b I just finished causes a nasty hum as soon as plugged in. The RK70j has to be turned all the way down.