Cobra 25 Ltd ROC unidentified Mod..?

[Redbandit]

Sammy or Claude, I also have a Cobra 25 Ltd. A gift from a brother in-law. He told me it has a mod, except he doesn't know what mod. Its a smaller pcb with wires running about. The thing is, there is a red wire that came off its solder point (where ever that is) and I have no idea where it may belong. When I turn it on, the needle shoots to the 30 range and doesn't change from there when I key the mike.

I am more interested in finding out what that board is, an echo or a beep? And if you have done a mod on any of your radios, where might that red wire go? ( see Photos). Thanks,

John

[163TM847]

Its a beep [Single tone], Red usually indicates positive supply and may have come off the positive connections on the back of the volume control.

[14CS06]

Hello John

I do not know this modification
Nick has the correct answer

The PCB PC-417 is the same as

COBRA 21 GTL



COBRA 25 GTL



PRESIDENT AR-44



@+
Claude

[Redbandit]

Just learning to move about this forum. Thank you Nick, for that shed of light. I was assuming that red was a power supply wire, but was sure bcuz the orange wire is thicker. That usually means it can handle some current. I had tried slightly touching it to that volume control source, and I would hear the relay click.

The Problem I see however, is that as soon as its turned on, the needle shoots to the complete right. (See Photo). That superstar mic you see there is new. I bought it a day ago, after I took the photos. Although I did try turning it on with the mic attached, it still shot to the right, I'm wondering if attaching the red wire, now that it has a mic, might bring the needle to its normal position?

Also, the mic is superstar DM507-4 for cobra radios. But I wonder if the pin numbers/color wires are correct. This mic has: 1-shield, 2- white, 3- red, 4- black.. Odd enough, I've looked on Google and find just the pin number and its function but not a color code chart.
Could you let me know if this is correct. Thank you,

John

[Redbandit]

Nick, my best guess is that you are correct that the little pcb is a roger beep mod add on. I took a chance and touched the red wire to the red of the volume wire and held it while I keyed the mic, when I let go, I heard a faint beep at the speaker. I imagine it would sound louder when its heard by others. I also saw the tx light turn red.

Now, as to where it was soldered to,. I took a look at both red and white wires on the volume pot, and the red solder connection is undisturbed. However the white wire connection is. And there's a drip of solder down below it on the meter, which kinda pushes my theory that this red wire was soldered poorly to the white one, and therefore fell off. Would it be safe to solder it back there?? (see photo).

Another odd thing is, that when I key the mic in testing the red wire, the needle moved down from the 30 to the 3. When I let go it went back to 30. I believe its supposed to be all the way to the tip of green, right? In either case, I only hear static snow, no chatter at all. Thanks again Nick.

John

[163TM847]

I couldnt tell you the colour code for the mic because i dont know what colour is connected to the PTT switch inside the mic, If you could post a photo of the PTT switch inside the mic then i could tell you which wire goes to which pin on the plug.

But even with the red wire off the beep board the radio should still have RX

Me personally i would remove the beep board and put the original wires back to the mic socket, The blue and orange will be the RX audio and TX wire [Which one is which i cant say from photos] But it would be very simple to figure which is which by touching the end of the wires to a ground source, One will give RX audio one will put the radio into TX then put the wires onto the mic socket the correct way.

[Redbandit]

Thank goodness this mod is actually a Roger beep, and I already connected the loose wire, it works.

However, I have question, it regards a weird result in keying up this radio. I've included photos. The issue is that while connected to a fire stick antenna, the radio is receiving and needle is by the 7 sig mark. When I key the mic, (with the RF all the way up), the needle drops to the far left green.

When I back the RF knob to middle, the needle rests at the far left green. When I key, the needle just moves forward and rests on the letter G of sig word. In either times, when I speak the needle doesn't move a hair.

I'm wondering if its a bad antenna (which 3ft antenna, coax and mirror mount) are supposedly new. I have it on my Apt window and I added a ground wire from mount to a wall electrical outlet. Before the ground wire, I didn't receive well, after wire I began hearing faint chatter.

I'm open for suggestions, opinions or an Axe.. hehe. Oops, last photo didn't load, its on next pg..

[Redbandit]

When I back the RF knob to middle, the needle rests at the far left green. When I key, the needle just moves forward and rests on the letter G of sig word. In either times, when I speak the needle doesn't move a hair..

??

[163TM847]

Regards to the signal, that could be outside noise being picked up, That is a common problem nowadays, The low TX could be bad antenna or an issue with the radio itself.

Where are you located ?

[Redbandit]

In regards to giving this thread a closing answer/solution,, I discovered that the antenna mount's nylon washer, although there, did not have an inner lip edge on the inside to keep antenna plug from touching the metal edge! This was causing a short. I had taken it at face value that the gentleman who gave me this new antenna, mount and coax knew the importance of keeping the antenna mounting post in the exact center, but he didn't.

I pulled it apart and discovered it. So in efforts to keep that center post from shifting when you tighten nut, I made a nylon guide guide washer that would stay in between and keep it centered. It worked. Needle on radios operate.

[Redbandit]

Forgot to post photos of mount fix.