Cobra 138xlr dead on lsb only

[groundwire]

http://nettyelectronics.com/crystals.html

Canadian site that has one listed. 2$ ? + $7 to ship it to USA in a padded mail envelope.

nope, tried him. this canadian guy you have to email him, then when he responds 4 days later he says send him a check and what i want. hahaha, a check? whats a check? hahaha, its not 1972 anymore. whats with these small guy sites, no add to cart, pay, ship. simple. send a check, hahahaha it still makes me laugh. anyway the search goes on i guess. if i knew some other radios that have it i would buy one for the part, even another 138xlr. but people want a mint for them for some reason. well i know one thing, if it doesn't get fixed in short time into the garbage it goes, just like the other radios.

 

[357]

swap the usb or am crystal into the lsb socket and see if you get output.
If you dont, its not the crystal

I just dealt with this issue on a cobra 139xlr and had to steal one from my 458 to get it running.
Someone tried to swap this silver crystal in and it was too far off to trim back to frequency.

 

[Handy Andy]

Hmmm...

Have you tried "torque-ing" the Xtal?

Ok, work with me here...

IF the Original tech that put this together has to tweak a Xtal - you can make some Xtals re-fire buy just placing a little stress onto one of the leads to press the contact back onto the grain and make it ring again.

Had this type of problem on 455kHz multi -pole (black box) murata filters, just had to fiddle with the leads of the xtal with hot soldering iron to re-melt and reposition the filter leads - keep working in one direction on the filter as you re-melt the leg(s) individually, use a ceramic tip tool to press on the lead leg you're working on - to see if pressure can be applied onto the filter and listen for the RX to return - once found re-melt with the correct pressure and allow the solder to cool and make the radio receive again.

You can do the same thing on a xtal - you just have to find which leg requires the torque to be applied to make it rub the grain and complete the circuit.

Sometimes it works, because the radio when it was made, one or more of the parts were soldered under a little more pressure than the others, causing the soldering to cool under the part, at different rates placing the part under stress - you might be able to recover the part by seeing if a re-melt and re-applying pressure to the part, while you solder one leg and try another direction with one soldered leg, with you re-melting the other leg to see if the position can restore the original torque onto the board can make the parts' inter contacts start working again.

You have a Xtal that was working, now it appears dead - you have nothing to lose in trying to make it work again..

 

[groundwire]

Hmmm...

Have you tried "torque-ing" the Xtal?

Ok, work with me here...

IF the Original tech that put this together has to tweak a Xtal - you can make some Xtals re-fire buy just placing a little stress onto one of the leads to press the contact back onto the grain and make it ring again.

Had this type of problem on 455kHz multi -pole (black box) murata filters, just had to fiddle with the leads of the xtal with hot soldering iron to re-melt and reposition the filter leads - keep working in one direction on the filter as you re-melt the leg(s) individually, use a ceramic tip tool to press on the lead leg you're working on - to see if pressure can be applied onto the filter and listen for the RX to return - once found re-melt with the correct pressure and allow the solder to cool and make the radio receive again.

You can do the same thing on a xtal - you just have to find which leg requires the torque to be applied to make it rub the grain and complete the circuit.

Sometimes it works, because the radio when it was made, one or more of the parts were soldered under a little more pressure than the others, causing the soldering to cool under the part, at different rates placing the part under stress - you might be able to recover the part by seeing if a re-melt and re-applying pressure to the part, while you solder one leg and try another direction with one soldered leg, with you re-melting the other leg to see if the position can restore the original torque onto the board can make the parts' inter contacts start working again.

You have a Xtal that was working, now it appears dead - you have nothing to lose in trying to make it work again..

Makes sense. I will try it and report back

 

[groundwire]

No bueno. I tried heating the leads with the iron and tweaked the leads a bit, no dice. Oh well. I did get in touch with the netty electronics guy and he had an exact replacement in stock and takes paypal so i ordered it. Comming from canada usps with tracking. Should be fun watching how long this one takes, if they dont lose it which they just might. Hahaha, i hope it doesn't take like a month to get here, that would suck. If it works and the radio is all good, next is 86 that speaker mount thing. Im just going to drill the case and mount the speaker to the bottom cover like all mobile radios. Thats like 3lbs of weight loss right there. That speaker thing adds sooo much weight. The radio weighs a ton, its crazy.

 

[groundwire]

The xtal came in from canada, 1 1/2 weeks, not bad. I put it in and BAM! It works great. I have not checked yet but im sure it might need a touch up on the frequency alignment because of the new xtal. Now to shed some weight on the 2 ton radio and see if it talks loud and proud. Thanks everyone for your input