87 GTL

[stingray]

hello! first post here. i just accuired a Cobra 87GTL NEW IN THE BOX from 1978! i believe it is the same board as the 89 and 1000 GTL.
i can not find any info on swing kits for this radio. from the factory it has a 2028 driver and 2029 final. this sounds like it will be pretty wimpy?
should i put a 1969 in?
i would like any advice on how to really get the most out of this radio and any help will be greatly appreciated. thanks!

 

[BOOTY MONSTER]

welcome to the forum stingray .

what is the radio doing for dead key and modulated power ?
im guess you have an external meter to check with .

 

[unit_399]

The 87GTL was a pretty good radio. Before changing anything, I would give it a good tuneup. Adjust L17 for max output. VR6 is modulation adjust. If you want to defeat the mod limiter, remove C128. Adjust VR201 for 15.0 vdc at the emitter of TR201. CBTRICKS has a schematic on its website. As I remember, this was a strong radio even with the stock driver and final.

- 399

 

[stingray]

i saw on cbtricks it says to cut d16 for the audio.
is this something different than removing that C128?
i have not gotten it to my house yet so i do not even know what kind of wattage it is doing yet. i have another 87 and d16 is cut and it has massive audio.

 

[unit_399]

you can cut the diode or remove the cap. Same result.

- 399

 

[stingray]

ok. so looking at the schematic i see tr201 is in the power supply .
so the p.s. output should be set at 15 volts. thanks.
i would love to be able to Mosfet this thing.
if it can be done to cobra 29's, what about this 87gtl?
how about at least a swing kit?

 

[MisterFatty]

the old "Supertalk" module works pretty well on that chassis. You can Google it for more info... Its just a couple bucks worth of parts. I have an 89GTL here, was going to Do a Mosfet conversion on it, but truthfully I haven't bothered, the radio has some nice audio without it. Did do the Supertalk as I wanted an easy variable output on it...

 

[stingray]

the old "Supertalk" module works pretty well on that chassis. You can Google it for more info... Its just a couple bucks worth of parts. I have an 89GTL here, was going to Do a Mosfet conversion on it, but truthfully I haven't bothered, the radio has some nice audio without it. Did do the Supertalk as I wanted an easy variable output on it...

hey there fatty! do you have instructions for mosfet for these radios
(87 and 89 gtl) i clipped the audio and it is unbelievably LOUD
everyone wants to buy it from me! all the wax is still on all the pots and it is dead keying 8 swinging up to 15! stock. this one is brand new from 1978.
i have another one that is used and i would like to experiment with a mosfet on it but cant find any info for these radios.

 

[BOOTY MONSTER]

oops. too late !!

 

[stingray]

oops. too late !!

2 late 4 what?

 

[MisterFatty]

nope I've not seen a Mosfet Mod on it, I was just going to sit down and do it, but like I said the radio works quite well without bothering..