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

Cobra UK 25 LTD ST

Hello everyone i have 2 of the above rigs, one has TX fault-will tx for a while then tx stops working but led changes colour, just no swing on meter, if i give a little (i know i shouldn't) "bang" on top it starts working again and does same on and off all day-another website says to check C118 but not sure what to check for!

2nd rig has a problem quite common to these boards-very low RX but no PA unlike others on here-i am suspecting TA7222 but see from other posts that if TXing good audio then amp must be ok-is this so? does audio ic control both RX and TX audio? BUT the cap next to audio amp has brown stains over and around it-even on the inside of the cover, could this be the culprit?

i do know that this rig has had 24 volts through it but worked after that so maybe the fault came as a result of this

any help will be much appreciated-tia
Joe

hello there,,welcome to the forum..i would say that on the first 25 youve described,the problem is probably a poor loose solder connection..find you a plastic scratching tool,power up the unit,and gently scratch around on the solder side of p.c. board,until you find the general area,,solder all solder points in this area..also a large magnefying light helps spot the bad connection,it will often be what we call moonringed..on your second rig with the low recieve,do you know if maybe a radio with a amp on has been keyed up close by..if so this is a typical problem,youll need to check d1 and d2 for shorts and or open conditions..these are the recieve overload diodes......good luck with your radio........ramblingman

Thanks for the reply Ramblingman

I will have a look at them over the week, don't think recieve has been overloaded in the way you described though-this was my mates rig and we used to run together on nights but i went on to days and he never used it again, but like i mentioned he DID plug it into 24 volt socket on wagon and wondered if this might have caused prob.

Thanks again and cheers for the welcome-will be back soon

Regards

Joe