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

NightRanger3151

I tried many things to get that frequency counter working. Replaced all resistors, did all the fix's I could find online etc. Ended up just buying one on eBay that worked and put it in. Still working today.

NightRanger3151

148 gtl Mic Wiring
Stock
1- Audio (White)
2- Shield (bare wire)
3- Receive (Blue)
4- Sw Com (Red)
5- Transmit (Black)

NightRanger3151

Maybe this will help ....

NightRanger3151

Looking for a 11.1125 Mhz Crystal. Found in Cobra 140 GTL, 142 GTL, President Washington and other radios which used the MB8719 PLL.

NightRanger3151

I just had a SSB radio done for $30. But that was in Indiana. Maybe prices are different in your part of the country.

NightRanger3151

Anyone ever added an external frequency counter to a Cobra 2000 GTL? The original one doesn't work. I'm wanting to add a Galaxy FC347 or FC30BT or Texas Ranger FC390 type to it. Looking for the locations where to connect the wires on the PC board. I know it's been done on the Cobra 148 gtl's, hoping...

NightRanger3151

I put the 1N4734 diode in D528 and it made no difference at all.

NightRanger3151

Hi: Does the Frequency change when you move the selector? If not then this would point to a PLL or Power supply fault. Check the voltage on pin 9 of the MB8734 PLL chip, it should be 8v DC if not then this points to a power supply fault & you should check the MB3756 regulator etc. Apparently th...

NightRanger3151

Radio Make and Model: Cobra 2000 GTL PCB Number: Main PC-497AB PLL Number: MB 8734 Test gear available: Symptoms: Frequency Counter is stuck on 92.2000 on receive and 0.0000 on transmit. What is working: Radio works fine, except for frequency counter. What has been tried: I did the improvement on th...

NightRanger3151

Well shoot, I thought somebody here might be able to point me in the right place to start looking.

NightRanger3151

Radio Make and Model: President Adams PCB Number: PC-346 PLL Number: 858 Test gear available: Power/SWR meter, Dummy load, Analogue Multimeter, Soldering Iron and solder, De-soldering pump Symptoms: Weak receive on all bands (AM,USB,LSB) If someone is close (within a couple miles) I can hear them, b...

NightRanger3151

Wanting a Sams Photofact CB-176, March 1978 book. Thanks.

NightRanger3151

Talked to president electronics and have been able to find out from the serial number it was made in 1977.

NightRanger3151

Is there a source anybody knows of to look up production dates of radios? Or a way to find out when a radio was made? I'm mainly trying to find out when my President Adams CB radio (made in Japan) was manufactured. This is the second one I've had and I couldn't pass it up. It's in excellent shape, ...

NightRanger3151

Thanks Dave! Your tip led me to checking all the connections from the PLL to the channel selector switch and I found two loose diodes from some pretty poor looking solder work. I fixed those two and touched up some other spots and the radio seems to be working great. Time will tell I guess. Thanks a...

NightRanger3151

how do you know the channels are all messed up, without a freq counter??? Because I have 4 other radios and when someone talks on the other radios down the road I can hear them on two different channels. And when I talk to them one of the channels that are messed up they don't hear me on that chann...

NightRanger3151

I have a President Adams CB. It's in great shape and doesn't look like it has ever had the case opened until I replaced a meter bulb in it. Problem is many of the channels are on wrong frequencies on both TX and RX. I'll try to clear this up better. Channels that seem to work correctly are 1 to 7 .....

NightRanger3151

If the power meter you are using to check this radio only measures average power, then that's probably why you're seeing backward swing... if you get a meter that reads PEP (forward swing) it might read different, your radio might not have anything wrong with it. Just a suggestion. -Exit Even if it...

NightRanger3151

woody wrote:what kind of mic are you useing on this radio?

I've tried different ones. Currently a RK-56.

NightRanger3151

Thanks for the reply. VR5 isn't turned down .. In fact it was turned almost all the way up and sounded as though it was over modulating. I got it to sound better by turning it down to about half way.

I've ordered another watt meter and will see what it shows. Should be here this week.

NightRanger3151

Not finding any cold solder points at all on this PC244. I believe I may have a bad AM regulator but not sure. Can you tell me how to check it? Have been doing some reading on some unidens that had similar problems and even found a mod on the PC122 that you could do to keep the problem from happenin...

NightRanger3151

just a thought did you check for any cold solder joints. Also check the am regulator. I would start by keying the radio and flex the board a little bit with you finger and see if you audio comes back intermittently. I would have to look at the schematic to be able to tell you much more. I will see ...

NightRanger3151

I just picked up a used Uniden PC244 AM-SSB radio. SSB works great, but there is no forward swing on AM at all. I can set the dk (vr10) anywhere from 1/2 watt up to about 7 watts and have no forward swing when I modulate. If I turn it above 7 watts it will begin to swing backwards. The swr's on ante...

NightRanger3151

Debs on Ebay does them for the 2000. Just tell her what color you want and if there are any changes to the faceplate that need done such as buttons being different from modifications etc. If you just want a new black one she can do that too. It may take her a while to respond though so try and be pa...

NightRanger3151

Pioneer621,

Thanks again! That worked to perfection! I have been annoyed by that ever-so-slight noise everytime it gets real quiet around that radio. I'll enjoy it more now.

You da man!

NightRanger3151

NightRanger3151

NightRanger3151, I have experienced that same thing with my Cobra 29 LTD’s, it probably has done it on the few dozen or more I have worked on, they must be designed like that. The noise is strange, it is kind of a muffled up static that is heard through the radios speaker when the SQUELCH is just a...

NightRanger3151

If the Cobra 29 is the LTD Classic model, then set the Squelch control on the front of the radio to 12 a clock, then slowly adjust VR3 so the radio just go in to squelch. The squelch is working just like it is suppose too from the factory. But when it just goes into squelch you can still hear a fai...

NightRanger3151

Smitty wrote:RF gain........

no

NightRanger3151

I have a Cobra 29 LTD. The squelch on these radios never completely quiets the radio unless you turn the squelch all the way to the right. Why Cobra did this I'll never know. I know of a lot of people that don't like the way the squelch operates on the 29 LTD's. Is there a fix for this so it will pe...

NightRanger3151

Does anyone have any info on the President Adams AM/SSB radio? I have one and would like the schematics and adjustment locations for it. Right now I'm trying to figure out how to align the clarifier back to center. The clarifier on this radio need to be turned all the way to the right to work on AM ...

NightRanger3151

Thanks for the reply redeye. Is the IRF520 the same as the ERF2030? I've read in some forums that it was. Do you know if it is?

NightRanger3151

Can the Irf510 mosfet from radio shack ($1.99) be used in place of a 2sc1969 or 2sc2078 final? Does it need the companion part like a IRF520 or ERF2030 does and what should the voltage at the gate be? I was thinking of trying this on a cobra 29 ltd with the 2sc2078 or a Galaxy DX959 that has the 2sc...

NightRanger3151

Which of these mods is the best to do on a Galaxy DX959? Or can a combination of both be done? I want it to last so I don't want the radio to get hot or anything. Any input would be appreciated. http://www.radiomods.co.nz/galaxy949_959ept069610z.html http://cbtricks.com/miscellaneous/fet_papers/ekl/...

NightRanger3151

Pioneer621, I tried the 1k resistor idea on the Astatic echo board and the cobra 29 LTD is talking loud and proud! I can set it to full echo and reverb if I want (not that I would use it like that) and with the dynamike set at full even with a power mic and this thing won't do the feedback anymore! ...

NightRanger3151

Hello! Just thought I would give an idea of what I have done to eliminate the RF feed back type problem with the echo boards. I have installed a couple dozen or more of the ASTATIC echo boards in Cobra 29 LTD's (most versions of the 29) & have encountered that very same problem, MANY times! The...

NightRanger3151

ok after reading this again I'm not sure what you mean by 'Pin1 to ground on the mic socket'. I thought Pin1 was the ground on the mic socket?

NightRanger3151

Rick wrote:Try soldering a 1n to 10n disc cap from Pin1 and 3 and from Pin1 to ground on the mic socket.

mmmmm, ok thanks. Not sure I will get to it tonight but I will try.

NightRanger3151

Here's more info ... I removed the mic and connected pins 1 and 3 and the noise was gone. I have an old cobra mic that has had the mic removed from it and I hooked it up and keyed and no buzzing either. A soon as I hooked the mic back though the noise was back.

NightRanger3151

I mounted it to the chassis of the radio. but I've also tried it not mounted. With it not mounted the noise is not as bad.

NightRanger3151

Found this on the internet ... This is exactly what mine is doing. 'Trouble Shooting CB Echo Reverb Audio' One of the most frustrating problems that often occur when adding power microphones or external Echo Repeater effects boxes or boards to existing radio installations is RF feedback or looping (...

NightRanger3151

Sounds like a Ground loop problem. Make sure the power to the Echo board power is taken from the Emitter of TR23 (8 VDC) and board is grounded to a tuning can or good known ground. Hear a trick to try first, make sure the radio is not touching the vehicle chassis and remove the antenna and connect ...

NightRanger3151

I hooked the ground wire back up to the echo board and grounded it and both grounding mic wires to a tuning can and it still does the same noise. grrrrrrrrrrrrr.

NightRanger3151

sonoma wrote:forgot that mine was fine on the base also.it only did this in a peterbuilt truck.moved it to a kenworth and it did not do this.

Thanks will try moving the ground. After grounding to the cans did it work in the Peterbuilt?

NightRanger3151

hard to explain so I took a video of it. You can watch the video here http://www.youtube.com/watch?v=Uvgz7ml7bpM the last few seconds of the video is the problem with the radio in the car with echo board installed.

NightRanger3151

I got the echo board hooked up at 8.1 volts and there was still no difference. I really am beginng to think it has something to do with my antenna. Especially since it works so well when i hook it as a base radio. But if it, is it isn't showing up on a swr check.

NightRanger3151

ok, will try again. I tried it on a spot that was 10v but will try to find or create an 8v and let you know. Thanks.

NightRanger3151

Here is some pics. I had the ground hooked up but have disconnected it so it wouldn't loop and am just using the ground from the mic connector that the black wires hook to as the ground.

NightRanger3151

Hello all, New member here. I've got a problem I am having a hard time figuring out with my Cobra 29 LTD. Please take a look at the video and see if you may have a suggestion as to why my radio is acting up as a mobile unit. It only started this after I added an Astatic Echo board to it. What's weir...

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

Search found 48 matches

Re: Frequency counter problem

Re: Cobra 148 mic wiring

Re: Cobra 2000 GTL Sideband Issue.

Crystal needed

Re: Help Cobra29ltd Classic

Adding frequency counter to a 2000 gtl

Re: Frequency counter problem

Re: Frequency counter problem

Frequency counter problem

Re: President Adams receive problem

President Adams receive problem

Sams Photofact

Re: How old is my radio?

How old is my radio?

My CB has duplicate channels - why?

No Swing on AM - Uniden PC244

Re: Cobra 29 LTD Squelch

Cobra 29 LTD Squelch

President Adams Radio Information needed.

IRF510 mosfet in place of 2sc1969

Galaxy DX959 mod - which one to do?

Re: Cobra 29 LTD Astatic Echo Board trouble.

Re: Cobra 29 LTD Astatic Echo Board trouble.

Astatic Echo Board troubles