Cobra 148 is only putting out 2 watts on SSB?

[tecnicoloco]

I can tell you get all your info from the internet and not a bit from actual experience.
Most CB radios and some exports will sound just fine after clipping the AM mod limiter. Clipping a limiter in quite a few exports will make the radios sound like crap.
You should know all this from your vast few weeks experience in CB radio.

Here we go again :sneaky2:

 

[Eastside]

From what I'm seeing so far, it almost sounds like it's an alignment issue. However, I have seen the C1969 finals go low gain in some of the older Taiwan radios. If the final goes low gain it can key up full power on AM, but won't have much for modulated output, and SSB power will be low. In some cases, a bad capacitor will also cause a problem. Hard to make out the issue if I don't have it on my bench in front of me. LOL

But if it were my radio, I'd get it put back to stock, undo any mods and give it a good alignment. Get it to square one before any troubleshooting is to be done. Good luck!


~Cheers~

The radio is not bad cosmetically and there are no added flip switches....and the switches that come on the radio do what they were put there to do.....the only thing my untrained eye noticed was that the r131 was clipped and that the white heat paste under the finals was thick and dry on one and real thin on the other.

 

[Eastside]

Some pics of the board.

 

[ExitThirteen]

If you adjust VR11 (the SSB ALC adjustment), does it function as it should? Meaning that you turn it all the way counter-clockwise, you get just about no output at all? Or if it still puts out 2W, no matter where you have it set? Let me know.



~Cheers~

 

[Eastside]

If you adjust VR11 (the SSB ALC adjustment), does it function as it should? Meaning that you turn it all the way counter-clockwise, you get just about no output at all? Or if it still puts out 2W, no matter where you have it set? Let me know.



~Cheers~

I would have to check again....I will let you know.....I will hook the radio back up and check it right now....it will take me a minute or 2.

 

[Eastside]

Ok....the trimmer is working....on lsb with the trimmer turned all the way up I am getting 4 watts....turned all the way down I am getting 1/2 watt.

 

[tecnicoloco]

Just send you radio to a qualified tech like DTB Radio

 

[ExitThirteen]

Well, since the ALC circuit is functional, I'd suspect an alignment issue. Although I have seen the final go low gain, it's pretty rare that it happens. I'd get it to a tech to have it put back to stock (any mods that can be seen are undone) and aligned. This is what I normally do when I get a radio across my bench that has a TX issue.



~Cheers~

 

[Eastside]

Just send you radio to a qualified tech like DTB Radio

If possible would like to get it fixed without having to ship it off.

 

[Eastside]

Well, since the ALC circuit is functional, I'd suspect an alignment issue. Although I have seen the final go low gain, it's pretty rare that it happens. I'd get it to a tech to have it put back to stock (any mods that can be seen are undone) and aligned. This is what I normally do when I get a radio across my bench that has a TX issue.



~Cheers~

Any tips on anything to check first....I do not want to put much money into this old of a radio.

 

[Robb]

Any tips on anything to check first....I do not want to put much money into this old of a radio.

Probably better off with this radio that with a lot of others. Is it a Philippine or a Malaysia build? Look at the small plaque on the back of the radio to find out. It is a 5 pin side mic radio I can tell. Either country of mfr is xlnt.

Just aligned two Cobra 148's, a Cobra 2000, and a Grant XL over the last week. All were Malaysian or Philippine and all are xlnt. Minor repairs, such as stuck meters and all definitely needing alignment. One had a bad variable cap for the USB output oscillator so I replaced it.

IOW; they are worth fixing and still fetch a fair price if they are in decent condition. The guy who owned these radios gave me one of the 148's, a Philippine at that. He didn't need it and wanted to do something for me since I didn't charge him for the work. It is a keeper and was given to me by a friend. It was mfd about the same year your radio is.

I think the driver and final bias adjustments should be done first.
Then peaking the TX cans as previously mentioned in an earlier post.
IMO . . .

 

[Eastside]

Probably better off with this radio that with a lot of others. Is it a Philippine or a Malaysia build? Look at the small plaque on the back of the radio to find out. It is a 5 pin side mic radio I can tell. Either country of mfr is xlnt.

Just aligned two Cobra 148's, a Cobra 2000, and a Grant XL over the last week. All were Malaysian or Philippine and all are xlnt. Minor repairs, such as stuck meters and all definitely needing alignment. One had a bad variable cap for the USB output oscillator so I replaced it.

IOW; they are worth fixing and still fetch a fair price if they are in decent condition. The guy who owned these radios gave me one of the 148's, a Philippine at that. He didn't need it and wanted to do something for me since I didn't charge him for the work. It is a keeper and was given to me by a friend. It was mfd about the same year your radio is.

I think the driver and final bias adjustments should be done first.
Then peaking the TX cans as previously mentioned in an earlier post.
IMO . . .

It is a Taiwan made one...cosmetically its in pretty good shape for a 20+ yr old radio.
Your tutorial for the hifi cb was pretty good....mebbe you should do a cobra 148 alignment tutorial for guys like me that do not know how.....I read how its done in the service manual....but that is assuming you are a tech and have all the equipment......I have a watt/swr meter and a digital multi meter and that is it.

 

[Eastside]

Well the ebay guy who sold me the radio refunded my money and told me to keep the radio and fix it or sell it for parts...just wanted me to give him pos feedback.
I don't know whether I will buy another 148 or have this one fixed...hmmm?

 

[ExitThirteen]

Depends on what kinda of funds you want to put into it... if it's cosmetically in good shape, you could be alright with putting a little coin into it to see about getting it fixed. The radio is worth it. I'd be willing to take a look at it for you, if you decide to part it out. I'd hate to see something like that go to the boneyard without my eyes on it... it might be something simple. It's up to you.


~Cheers~

 

[Eastside]

Depends on what kinda of funds you want to put into it... if it's cosmetically in good shape, you could be alright with putting a little coin into it to see about getting it fixed. The radio is worth it. I'd be willing to take a look at it for you, if you decide to part it out. I'd hate to see something like that go to the boneyard without my eyes on it... it might be something simple. It's up to you.


~Cheers~

I will have to think on it.