Install a 22k-220k ohm resistor between these two points. Receive Boost: Locate pin 14 of the PLL chip, and the Positive (+) side of C-12. You can also try removing R125 and increasing the value of R102. For AMC changes, place 5k variable resistor from base of TR33 to ground. 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.
CRE 8900 PROBLEMS MOD
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.
CRE 8900 PROBLEMS UPDATE
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.
0 kommentar(er)
