cobra 89xlr no carrier

[troyota]

i have a cobra 89xlr with no tx. no dead key it does receive. it has had a different driver put in it at sometime c3953. was told it worked but it dont. can i put a 2166 driver and a 1969 final in this radio? does it have some of the same problems as the 139xlr? ie capacitor i dont hear a click when keying, but i guess there is good reason cause i didnt see a relay. is there supposed to be a keying relay?
thanks

 

[troyota]

i have found out more info on this rig. apparently it had low power like 2 watt key with 5 watt swing after full peak. they tried to get more power. first they moved the final to the driver spot, and put the 1969 in final spot, no luck. then they tried the 2166 driver and 1969 final, still no tx . they told me that the heat sink got warm on power up without tx. so im thinking it was the wrong pinout. then they put it back the way it was, no tx. maybe a parts rig now. anyway i am not touching it till i hear back from you guys.
thanks

 

[loosecannon]

these are the same as the 1000GTL, and basically the same as a 29LTD.

the stock driver is a 2SC2028, and the stock final is a 2SC2029.
both should be fairly easy and cheap to get.

you might be able to do the MOSFET final and driver mod as per the instructions for the 29LTD.

i have not tried it myself, but the radios are very similar.

better get some second and third opinions on this before you try it.

good luck,
LC

 

[troyota]

the reason i was asking about 2166 and 1969 is because i have them in stock. are they pinned out the same? anyone know if they will interchange? also if there are anymore problems known on these?
thanks

 

[loosecannon]

the 1969 is pinned the same if i remember correctly, and i would assume that the 2166 is also, but to be sure; go to Welcome to CBTricks and go to the database section.

there you can find the datasheets for all four of these transistors and make sure the pinouts are the same.

the thing about using the 2166 and the 1969 is that they will require other parts to be changed to make them work.

that is best left to a good tech.

we have a few of those here on the forum, and im sure you could find out who without too much trouble.
i dont want to publicly endorse anyone, as i have never used any of their services.
i just know who knows what the heck they are talking about and who doesnt.

good luck to ya!

i own one of these bases, but havent messed with it at all yet.
sorry i cant be of more help to you.
later,
LC

 

[troyota]

thanks lc, i wasnt aware that other parts may have to be changed. well for those knowlegeable. is it possible other parts were damaged when this was tried before? (2166 and 1969) meanwhile i will try to see if i can locate some original parts for the radio. oh yeah BTW i think you got a couple numbers mixed up on the finals on the first post please correct me if im wrong. the stock driver is 2sc2091 instead of 2028, stock final is 2sc2092 instead of 2029. the parts list on cb tricks says this.
thanks again

 

[loosecannon]

SO SORRY!

please disregard my previous posts, i was referring to the 89GTL not the 89XLR.

how embarrassing LOL

the good news is, there is a Technical Service Bulletin issued for this very problem on the 89XLR.
seems that this chassis was notorious for the no transmit symptom.

here it is:
http://www.cbtricks.com/radios/cobra/89xlr/graphics/cobra_89xlr_tb1219.pdf


good luck, i hope this works for you,
LC

 

[b wil]

SO SORRY!

please disregard my previous posts, i was referring to the 89GTL not the 89XLR.

how embarrassing LOL

the good news is, there is a Technical Service Bulletin issued for this very problem on the 89XLR.
seems that this chassis was notorious for the no transmit symptom.

here it is:
http://www.cbtricks.com/radios/cobra/89xlr/graphics/cobra_89xlr_tb1219.pdf


good luck, i hope this works for you,
LC

Ive looked at this bulletin and it didnt fix mine, I have 3 of these radio`s with the same problem, any other help available. thanks in advance

 

[loosecannon]

first, here is a page with a bunch of info for your radios:
http://www.cbtricks.com/radios/cobra/89xlr/index.htm

there could be many reasons for a radio to not transmit.
I don't think there is a relay in these radios, but if there is, check that it is switching over when you key the mic.

after that, its usually a bad driver or final, or the radio is out of lock. (assuming that the problem is actually inside the radio and that you aren't just trying to use the same bad mic to key all three radios)
Is there an RX/TX light on the front?
if so, is it changing from green to red when you key the mic?
this will tell a lot about where the problem is.

the truth is that these radios are just too old to be reliable and need to be re-capped.
all electrolytic capacitors in the radio need to be replaced as they are long past their shelf life.

if you don't do that, then no repair is going to make those radios reliable.
even if you do fix one, it is just going to break again as the caps age.
its just the sad truth of our hobby.
these radios were never manufactured to last this long, and they start getting finicky as time goes on.
best of luck with them.
LC