Cobra 89xlr low TX audio

[Copycat32]

Hi all was given a cobra 89xlr has great recieve 4 watts out pa audio works great 13.82 v but transmit audio is very Low maybe 2% at most with a D104 or sock mic don't have a schematic.. Any suggestions would be helpful thank you

 

[doffo]

I wonder if there is a capacitor or two that might be going bad. I had a Cobra 142 GTL that had basically no modulation but did have a carrier. Once I narrowed it down, it had a shorted cap. Replacing it brought the radio back. have a look inside to be sure there isn't visible signs of some capacitors on their way out.

 

[BC Coyote]

Hi all was given a cobra 89xlr

That is an absolutely ancient radio. It appears that it was last produced in 1979.
It will need to be completely recapped and aligned first and then you may find other problems too........
Not sure I would be spending that much time on an AM only 4 watt radio! It's not exactly a high-performance machine, and it's only worth maybe $100 in good working condition.

 

[Copycat32]

Hi all was given a cobra 89xlr has great recieve 4 watts out pa audio works great 13.82 v but transmit audio is very Low maybe 2% at most with a D104 or sock mic don't have a schematic.. Any suggestions would be helpful thank you

I wonder if there is a capacitor or two that might be going bad. I had a Cobra 142 GTL that had basically no modulation but did have a carrier. Once I narrowed it down, it had a shorted cap. Replacing it brought the radio back. have a look inside to be sure there isn't visible signs of some capacitors on their way out.

I purchased a cap kit for it.. Was running a signal injection through it and got some modification back fuzzy but more .. So I'll recap atleast the audio and output section did a recap of the. Power supply.. It's dead on frequency..
So I should get the kit Monday or Tuesday ans see if it fixes the problem.. It's a nice little prodject to do while recovering from surgery.. And the radio will be going to a friend that wants to get back into cb..
Thank You

 

[doffo]

I purchased a cap kit for it.. Was running a signal injection through it and got some modification back fuzzy but more .. So I'll recap atleast the audio and output section did a recap of the. Power supply.. It's dead on frequency..
So I should get the kit Monday or Tuesday ans see if it fixes the problem.. It's a nice little prodject to do while recovering from surgery.. And the radio will be going to a friend that wants to get back into cb..
Thank You

Get to feelin better. Recovery for sure takes time.

I got a couple of 21XLR radios and a couple of the 29 XLR. A couple are in rough shape but still work ok.

 

[Copycat32]

Get to feelin better. Recovery for sure takes time.

I got a couple of 21XLR radios and a couple of the 29 XLR. A couple are in rough shape but still work ok.

I have a couple 29ltd 25 gtl all work great a couple trams d300 D62 d42 love the. Old rigs my latest trc 457 love it great rig.. Rec2 from knee replacement surgery that got infected going back bto the or mobday to get reopened cleaned out.. I more rigs to work on after another w 89xlr a Johnson 250 and a recap a tram D201a and 2 Lafayette Comstats 25b and 35 enough to keep me busy for a while lol

 

[doffo]

I have a couple 29ltd 25 gtl all work great a couple trams d300 D62 d42 love the. Old rigs my latest trc 457 love it great rig.. Rec2 from knee replacement surgery that got infected going back bto the or mobday to get reopened cleaned out.. I more rigs to work on after another w 89xlr a Johnson 250 and a recap a tram D201a and 2 Lafayette Comstats 25b and 35 enough to keep me busy for a while lol

You got a nice list of radios to work on for sure. That 457 is pretty great. I only have the 458 though without the clock. 457 for sure is the better looking one of the two.

 

[Copycat32]

You got a nice list of radios to work on for sure. That 457 is pretty great. I only have the 458 though without the clock. 457 for sure is the better looking one of the two.

I the past 3 weeks I repaired a cobra 86 142gtl 139 Ltd uniden pro 750 and a pro 850.. Been out of radio since 87 getting back. Into It went through a my base mics 9 D104s eagles and standard a bunch of turners ssk plus 3n cs-1 plus 2. 1 ssk I built a new stronger amp great foe tube radio but s
To strong for a transistor rig works great on the tram D201a
Nice chatting 73s

 

[doffo]

I the past 3 weeks I repaired a cobra 86 142gtl 139 Ltd uniden pro 750 and a pro 850.. Been out of radio since 87 getting back. Into It went through a my base mics 9 D104s eagles and standard a bunch of turners ssk plus 3n cs-1 plus 2. 1 ssk I built a new stronger amp great foe tube radio but s
To strong for a transistor rig works great on the tram D201a
Nice chatting 73s

You are well on your way. Enough knowledge from the past it will be like riding a bike again. The 142 Radios I am fond of as that was probably the 1st base radio I seen as a kid. Very first CB was probably the Sears Roadtalker slant face AM radio. (Wasn't the SSB). Take care and enjoy the evening. 73

 

[BC Coyote]

my latest trc 457 love it great rig

That's a fantastic radio! I worked stations all over the world during sunspot cycle 23 with an expanded TRC-457, a Boomer 100 amp, and an Antron 99.
I also had a TRC-458 which has very similar electronics and is based on the same Uniden 858 PLL board.

I have a box in my loft with three defunct 457's in it. One day I'll combine them into a good working radio. If I can find the time before I die LOL!

 

[Crawdad]

Hi all was given a cobra 89xlr

I was 19 when I scrimped and saved and bought one brand new in '77. My first base radio. Can't remember how much but it wasn't cheap.

7 3

 

[doffo]

I was 19 when I scrimped and saved and bought one brand new in '77. My first base radio. Can't remember how much but it wasn't cheap.

7 3

Usually its fun going through old Radioshack catalogs and seeing the price of CB radios and then find out exactly how much that was in today's money. There is a website you can see old catalogs. Radio Shack Catalog Archive

 

[Copycat32]

I wonder if there is a capacitor or two that might be going bad. I had a Cobra 142 GTL that had basically no modulation but did have a carrier. Once I narrowed it down, it had a shorted cap. Replacing it brought the radio back. have a look inside to be sure there isn't visible signs of some capacitors on their way out.

I got into the rig there's an. Update I Wana. Do according to the factory bullitin.. Wana change tr14.. I have the replacement but can't seem to locate it in the board anywhere I see it on the schematic it not a heavenly populated board bot can't seem to locate tr14 don't have a sams only a schematic nand some paperwork I found on cb tricks any clue? Anynone
Thank You

 

[doffo]

I got into the rig there's an. Update I Wana. Do according to the factory bullitin.. Wana change tr14.. I have the replacement but can't seem to locate it in the board anywhere I see it on the schematic it not a heavenly populated board bot can't seem to locate tr14 don't have a sams only a schematic nand some paperwork I found on cb tricks any clue? Anynone
Thank You

I will open up my 29 XLR and see if I can find it on that board. should be the same on yours. Give me a moment to get a picture.

 

[doffo]

I thought I had a 29 XLR here, but apparently I dont. It was a 29 GTL that I had here. I found a video on a 29 XLR board, and hoping its somewhat close to what you have.