Thanks Robb, btw what do you think of this mod, will it work along with what you posted? Thanks Lee
1. Carrier Adjustment: VR10. If lower carrier is desired, change R196 near VR-10. Try about 270 ohms.
2. Change R114 to a 10K, and C46 to a .2 monolithic, this will widen up the audio on AM.
3. The AMC is TR-26. You can remove it, and still have good results on AM, the ALC for SSB is not effected by this. If you don't want the AMC disabled, leave it. the other way to disable the AMC is cut R131. Check both to restore AMC from previous mods.
4. If extra frequencies have been added, perform the following to widen up the band pass filters to recover lost power at the highest and lowest frequencies: C163 - 4pf, C41 - 3pf
5. R180 - Jumper it. This brings up the gain of the TX mixer.
6. IC TDA6130 - Pin 12 to ground through 100 ohm resistor. Upper left, pin 14 = ground.
7. Remove the AM regulator, (usually a 2SC1419) and replace it with a 2N6487.
8. C174 - remove, add 1000uf electrolytic. connect POS to base of yellow wire next to it. If the yellow wire is too far away, it might be easier to connect the POS leg to the leg of the AM regulator closes to the back of the chassis via the bottom of the radio.
9. For 148F, change C18 to a 1000uf electrolytic, 16V
The 2sc1674 change to a 2sc2999e I would not recommend. Mixed results; usually not favorable. Changing the four 1N60 in the receive and noise blanket diodes to 1N6263 is always a solid move and is recommended.
Awesome audio is what you want?
"Goldfinger's Cobra 148/2000/Grant XL audio mod"
TX
C46 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
C101 Change to 1.5uf tantalum 16 to 50 volt
C102 Change to a 910pf ceramic disc
C104 Change to 2.2uf tantalum 16 to 50 volt
C108 Change to 1uf to 2.2 uf tantalum 16 to 50 volt
I found that if you have a very deep voice start with 1uf on C108
and work up if need be.
If you need more highs on tx Change C 105 to .001 to .0001uf mylar/polyester film The smaller you go the more highs you get.
RX
C71 Change to 1uf mylar/polyester film or non-polarized electrolytic
C75 Change to .001 to .0001uf this will give you more highs on rx
optional
C76 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
C182 Change to .001 to .0001 for more highs on rx and tx
optional
C183 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
C187 Change to 2.2uf mylar/polyester film or non-polarized electrolytic
With C75 and C182 you can start with no Change to them, then if you feel you want more highs then change them out