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Cobra 148 GTL
- Thread starter DelR
- Start date
999 beat me to it, The AMC and ALC are both defeated if you do this.
Go read this whole thread before you proceed.
Good info in this one there is.
www.worldwidedx.com
73
Jeff
Go read this whole thread before you proceed.
Good info in this one there is.
Cobra 148gtl r131 removal?
So i need a solid answer here. On the old cobra 148gtl radios, 5 pin side mic made in Taiwan, if i remove r131 does it disable the modulation limiter completely, basically same as removing the transistor. Or does it keep the modulation limiter function working, with just a boost in am modulation?
73
Jeff
That's what I thought I had read one time. Talks great on AM, but no SSB. Basically made a cobra 29 out of it.999 beat me to it, The AMC and ALC are both defeated if you do this.
Go read this whole thread before you proceed.
Good info in this one there is.
Cobra 148gtl r131 removal?
So i need a solid answer here. On the old cobra 148gtl radios, 5 pin side mic made in Taiwan, if i remove r131 does it disable the modulation limiter completely, basically same as removing the transistor. Or does it keep the modulation limiter function working, with just a boost in am modulation?
73
Jeff
Wow, that is some kind of long winded post, but great information, just hard not to get lost in it. Looks like I need to buy me a anywho ares II, and sell it back to fleabay.999 beat me to it, The AMC and ALC are both defeated if you do this.
Go read this whole thread before you proceed.
Good info in this one there is.
Cobra 148gtl r131 removal?
So i need a solid answer here. On the old cobra 148gtl radios, 5 pin side mic made in Taiwan, if i remove r131 does it disable the modulation limiter completely, basically same as removing the transistor. Or does it keep the modulation limiter function working, with just a boost in am modulation?
73
Jeff
Cliff notes version:
Go find the post by Nomad in that thread about removing TR 26 and putting it in place were TR 24 should be.
This should allow you to at least control the ALC level on side band even if the AMC is defeated for AM.
If you have NO ssb at all, then that's a different question.
73
Jeff
Go find the post by Nomad in that thread about removing TR 26 and putting it in place were TR 24 should be.
This should allow you to at least control the ALC level on side band even if the AMC is defeated for AM.
If you have NO ssb at all, then that's a different question.
73
Jeff
If it's a 1979 Cobra 148GTL it probably has a handful of electrolytic capacitors gone bad from age and mileage both. And if one of the failed caps feeds mike audio to the sideband modulator, you would lose SSB transmit. Best solution for a radio that old is to replace every, last one of those aluminum electrolytic capacitors. Commonly called "re-capping" a radio.
Maybe. But if it's a 1989 Cobra 148GTL you may not have more than one or two of those capacitors past the "use-by" date.
And if it's a 1999 Cobra 148GTL it's still a bit early for that kind of failure to kill the SSB transmit audio.
If it's a 2009 Cobra 148GTL I would be looking for a solder glob bridging two adjacent copper foils where it shouldn't be.
If it's much newer than that it will say "148 GTL-D" on the serial number plate. I would be looking for faults in the factory soldering if it's that new. The "D" version has a spotty reputation, especially for sideband performance.
Any product that's on the market for that many decades will be revised and redesigned several times over. The country of origin can narrow down the age. Could be Taiwan, Philippines, Malaysia, Singapore or China.
Remember what Indiana Jones said in "Raiders". It's not just the years, it's the miles too.
73
Maybe. But if it's a 1989 Cobra 148GTL you may not have more than one or two of those capacitors past the "use-by" date.
And if it's a 1999 Cobra 148GTL it's still a bit early for that kind of failure to kill the SSB transmit audio.
If it's a 2009 Cobra 148GTL I would be looking for a solder glob bridging two adjacent copper foils where it shouldn't be.
If it's much newer than that it will say "148 GTL-D" on the serial number plate. I would be looking for faults in the factory soldering if it's that new. The "D" version has a spotty reputation, especially for sideband performance.
Any product that's on the market for that many decades will be revised and redesigned several times over. The country of origin can narrow down the age. Could be Taiwan, Philippines, Malaysia, Singapore or China.
Remember what Indiana Jones said in "Raiders". It's not just the years, it's the miles too.
73
Yes, I seen that about moving the TR26. I will have to open it up this evening when I get home and have a look. Thanks
