RemoveC119, and run a 1000uf cap from negative side of C119's position to the base of TR34, with the positive side of the 1000uf cap going to the base of TR34. However, there are a few mods that will yield better over-all PEP and still keep decent quality sound. I have found that the best over-all sound and performance comes with nothing more than a standard tune-up, with the AMC circuit left intact. I do not recommend extensively modifying the 140/142, due to the type of modulation circuit used. Supertune: Many of you have asked about supertunes for these radio. You may need to re-align the frequencies a bit. Wire a switch from Pin 10 to ground(SW-2 on the chart), and another from pin 11 to pin 12 (SW-1 on chart).

Isolate pin 10 from ground (Cut the trace). Locate the MB8719 chip (usually right behind the channel selector). Reset the AMC level for 100% modulation.Įxtra Channels: Replace the 11.1125 mhz crystal with a 11.3258 crystal. RemoveC174, and run a 1000uf cap from negative side of C174's position to the base of TR41, with the positive side of the 1000uf cap going to the base of TR41. I have found that the best over-all sound and performance comes with nothing more than a standard tune-up, with the mod level set for 100%. I do not recommend modifying the 148 very much, due to the type of modulation circuit used. Supertune: Many of you have asked about supertunes for this radio. Wire a single-pole, single-throw switch from pin 10 to ground (SW-2 on chart), and another from pin 11 to pin 12 (SW-1 on chart).

For safest operation, do not jumper any diodes.Įxtra Channels: Locate the MB8719 chip (usually right behind the channel selector). This does increase the output by a small amount, but it also causes a risk of extreme receive distortion when receiving high signal levels at high volumes, as well as a slight risk of component damage in the event of an overly-high inductive kickback voltage spike.

Note: Some tips mention jumpering a diode with a piece of wire. They are the result of my own experience and research. Note: These are NOT copied from any other source. Watch for new content as I get time to update this page. Most of these will be categorized by radio brand and model, plus a category for miscellaneous tips.

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