There was a thread here, but I couldn't find it. This was posted a while back as a complete set of mods for audio:
Also applies to:
Cobra 148GTLF
Cobra 2000GTL
Undien Grant XL
Uniden Grant LT
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
