Cobra 148 GTL production date Mar 1989 Phillipines

[LeapFrog]

Unlocked clarifier and ALC disabled
Reconnect (solder patch) or replace R129
TR25 TR26 should be present.

Re-locking the clarifier is a little more "advanced", lol.
The best thing to do when repairing a modified radio, is to search out modifications performed, and follow the steps in reverse order!

The circuit board in that radio looks like a keeper, nice rig!

 

[JLsenior]

Leap frog if I repair the snipped connections will I hurt the radio when iturn it back on or will it automatically limit tx and bring my needle back down.

 

[LeapFrog]

Leap frog if I repair the snipped connections will I hurt the radio when iturn it back on or will it automatically limit tx and bring my needle back down.

Repairing R129 will not damage a thing, but it should calm the needle down!
R44 and D52, leave alone for now.

You want to seek out the procedure for unlocking the clarifier, find every piece and you can go about completely reversing the mod, you don't want to "half lock the clarifier", or simply limit the slide, you should aim to make it "factory".

 

[JLsenior]

Thank you. I appreciate all the help.

 

[LeapFrog]

Thank you. I appreciate all the help.

No worries, one thing to look for when you find a clarifier modification is to see if the modder changed out the varactor diode, a "super diode" or any other funny business there can cause issues when you go to align the radio back to factory specification.

 

[Robb]

Might be best to deal with one issue at a time.
The clarifier mods is OK for now - IF it doesn't move too much Hz.

 

[Low_Boy]

Do worry about the modulation socalled clip/snip mods. Like Robb said you may want to leave the clarified alone.

 

[ExitThirteen]

Repair R129, and adjust both VR9 and VR8 so they are both at center (12 o'clock). These adjustments are located in front of the driver and final transistor. VR9 is right by the driver, VR8 is right by the final. These are both cranked fully clockwise, and this can also cause part of the problem you're having, as those two VR's control the bias current to the driver and final. Eventually, you'll have to get them re-adjusted again, but for now, just to try to get the radio going to where it doesn't act up, just set VR9 and VR8 in the middle, so give them each about a half a turn counter clockwise.

You can leave D52 and R44 clipped, no need to mess with those right now.

Let us know how you get on.


~Cheers~

 

[JLsenior]

I repaired R129, Set Vr8 & Vr9 to mid point turning counter clockwise. Now when radio is keyed, watt meter reads .5watt and the needle still slams to the red.with no audio into the mic. Turning down the mic gain and radio gain has no effect.Needle still goes fully pegged. Radio meter full pegged and secondary in meter shows the same. Swr reads 1.1.

 

[JLsenior]

No worries, one thing to look for when you find a clarifier modification is to see if the modder changed out the varactor diode, a "super diode" or any other funny business there can cause issues when you go to align the radio back to factory specification.

What does a "super diode" look like?

 

[BJ radionut]

http://downloads.cobra.com/CB/Models/148-SERIES/148alignment.pdf

http://www.angelfire.com/fl2/cbradiorepair/slidemyway.html

Maybe this will help...
GL
All the Best
Gary

 

[JLsenior]

Can I align the tx with out having a dummy load and just leave the antenna hooked up?

 

[Robb]

Can I align the tx with out having a dummy load and just leave the antenna hooked up?

You must have a dummy load to keep the load even on the output, so that any power adjustment will be accurate. If you are adjusting the output freq; then all you need is an antenna load. But whenever you transmit, regardless of the reason, there MUST be an antenna OR a dummy load on the radio.

 

[JLsenior]

Built my dummy load to 50ohm 25 watt max. On the klein it reads 50.4 ohms.......This .4 enough to cause issues or I can do the tx alignment?

 

[Robb]

Not perfect but should present a non-reactive load.