Mic Problems??

[OLDPROSPECTOR]

I have an Cobra 148 GTL-DX. Was recently checked out by a shop. They told me that it really was an Lafayette 2400 with Cobra Written on it! Anyway they checked it out and said it was on frequency, and that they could not replace the RF meter nor a segment of the LED. I might add, that prior to sending it to the shop I had not had it in use for a number of years and it was not until it was returned that had an antenna hooked up. When I got it back, I powered it up, lights came on, channels changed, etc. All was fine till I connected the mic. My ears were greeted by a strong tone. Disconnecting the mic the tone disappeared. I have another unit that I connected to the same power and antenna, that works perfectly. So I am about to wire up an old Turner power mic, I think it is something like 302, can't find any markings on it. Anyway I am confused. The radio takes a four pin mic, and I am wondering if I should wire it the same a most Cobra four pin plugs. Somewhere I was under the impression that Cobra sidebands used 5 pin plugs. So, Is the problem with the mic. If so the proper wiring of the mic cord plug. Look, I'm just an 80 year old digging out some long forgotten hobbies to entertain himself.

[AG3Y]

Sorry, "Old Prospector". This is a Amateur Radio forum, and it is quite likely that no one here is familiar with your Cobra radio. That is most likely why you haven't gotten any help with your problem.

You might be better off trying to locate a forum dedicated to CBers. They will probably have the answers you are looking for. I'm sure that you have something hooked up wrong, but what it might be is anybody's guess!

Good luck. Jim

[W0UZR]

Been too long since I monkeyed with CB stuff. The only thing I remember is the Cobra mic a lot of times needs to have 2 wires connected together for it to work. Can't remember which ones.

You have a computer, type in the Google Search

Cobra Microphone Wiring Diagrams

and see what comes up

[KA9MOT]

Hmmm....first time poster, with questions about his illegal CB..............

Troll Maybe?



COBRA 148 GTL DX

Band: 26-27.8 Mhz
Mode: AM|FM|SSB|CW
Power: 4-12W

Frequency range: 26-27.855 MHz Channels: 120 Frequency generation: PLL Power output: 4 W (AM/FM), 12 W (SSB/CW) Voltage: 13.8 VDC, Deluxe AM/SSB Mobile CB Radio with Dyna-Mike Plus,RF Gain, Automatic Noise Limiting & Blanking, LED Channel Display with Dimmer, PA, Voice Lock (Clarifier), Tone Control, Built in SWR Meter, RX / Xmit LED

From: http://www.dxzone.com/reviews/Detailed/19.shtml

[KB0MNM]

Since the microphone is an obvious problem, and the rig itself may also require some rework- I question why a real antenna:( was used for testing purposes. Cantennas, dry dummy loads, etc. have been around for a number of years. This same forum has previously had other threads about types of microphones ( high impedance vs low, electret, etc. ). If we as hams want to further on-the-air testing of a rig with known modulation problems, just offer a partial solution. I tend to believe that the service shop's statements about the circuit boards inside *may* be true- if the case of a Cobra is large enough to hold a Lafayette with room to spare. Should this be the case, a few seconds under the tires of a cement mixer may be the cheapest remedy:D. There are plenty of rigs available at low cost on the "general for sale" forum, and it is assumed that hams would convert them for 10 meter use. FCC Licensed amateur radio KB0MNM- Jon:)

I have an Cobra 148 GTL-DX. Was recently checked out by a shop. They told me that it really was an Lafayette 2400 with Cobra Written on it! Anyway they checked it out and said it was on frequency, and that they could not replace the RF meter nor a segment of the LED. I might add, that prior to sending it to the shop I had not had it in use for a number of years and it was not until it was returned that had an antenna hooked up. When I got it back, I powered it up, lights came on, channels changed, etc. All was fine till I connected the mic. My ears were greeted by a strong tone. Disconnecting the mic the tone disappeared. I have another unit that I connected to the same power and antenna, that works perfectly. So I am about to wire up an old Turner power mic, I think it is something like 302, can't find any markings on it. Anyway I am confused. The radio takes a four pin mic, and I am wondering if I should wire it the same a most Cobra four pin plugs. Somewhere I was under the impression that Cobra sidebands used 5 pin plugs. So, Is the problem with the mic. If so the proper wiring of the mic cord plug. Look, I'm just an 80 year old digging out some long forgotten hobbies to entertain himself.

[K7KBN]

Most CBers don't have enough money to buy something like a "dummy load" (and they're smarter than we hams: they know a "dummy load" don't put a buncha poundsa aaaauuuUUUUUddddiiiiiiioooooooo on the bowel [:D]).

They DO have money enough for a DaveMade, or WizardMade, or a Varmit [:D], Texas Star or whatever. Just none of those "dummy loads".

[VK2TIL]

Old Prospector;

Amateurs in the US are a bit "touchy" about CB; given the mess it seems to be in, that's understandable.

But a radio is a radio; it's the users that are the problem.

Your question is a legitimate one and what better place to ask it than on a forum whose members might be expected to know a bit about radio?

Here is the pin-out information you seek;

http://www.angelfire.com/ks/cbmods/mic.html

Note that your radio is 4-pin whilst other Cobras are 5-pin.

The Turner connections are 1. Shield & Red; 2. White; 3. Blue & 4. Black.

Stay legal & have fun!