Here we are again.
another Realistic chassis with no schematic or service info. to be found.
yes, we can find the modulation pot and the tuning coils for the driver and final, but thats about it.
so, in order to help those who may come across one of these units and want to give it a more thorough going over; here is a more or less complete tune up for this base station.
i cant really call it an "alignment procedure" because there are no test points/ specs. to use, so i'll just call it a "full tune up".
1. attach freq counter to antenna jack. channel 20. TX mode.
adjust CT1 for 27.20500mhz.
2. attach signal generator to antenna jack, and set for about S-2 on radio's meter.
adjust L1, L2, L12, L3, and L13 for max. S units.
check channels 1 and 40 for even receive gain. use L2 to balance.
3. attach wattmeter with dummy load to antenna jack.
adjust L5, L6, and L14 for max modulated wattage.
here are the VR's and what they do:
VR3 S-meter
VR4 Voltage Regulator (set for 13.8 volts on pin 5 of TDA2003 audio chip)
VR5 RF meter
VR7 AMC
VR8 Squelch
well thats about it.
pretty basic little unit, and dont expect too much in the way of "swing".
hope this helps someone someday,
LC
another Realistic chassis with no schematic or service info. to be found.
yes, we can find the modulation pot and the tuning coils for the driver and final, but thats about it.
so, in order to help those who may come across one of these units and want to give it a more thorough going over; here is a more or less complete tune up for this base station.
i cant really call it an "alignment procedure" because there are no test points/ specs. to use, so i'll just call it a "full tune up".
1. attach freq counter to antenna jack. channel 20. TX mode.
adjust CT1 for 27.20500mhz.
2. attach signal generator to antenna jack, and set for about S-2 on radio's meter.
adjust L1, L2, L12, L3, and L13 for max. S units.
check channels 1 and 40 for even receive gain. use L2 to balance.
3. attach wattmeter with dummy load to antenna jack.
adjust L5, L6, and L14 for max modulated wattage.
here are the VR's and what they do:
VR3 S-meter
VR4 Voltage Regulator (set for 13.8 volts on pin 5 of TDA2003 audio chip)
VR5 RF meter
VR7 AMC
VR8 Squelch
well thats about it.
pretty basic little unit, and dont expect too much in the way of "swing".
hope this helps someone someday,
LC