IC-2SAT-No Power On.
1) Cracked solder joints at battery connections.
2) Cracked solder at jumpers to VR unit.
3) Bad flex cable.
4) Problems on logic unit.
Check the resistance between the "E" and "-" terminals on the bottom of the radio. Should be 0 ohms.
Check the jumpers on the VR unit for cracked solder joints and repair as needed. If OK, verify proper logic board voltages as per the service manual. Failure here may mean a bad flex cable or faulty CPU crystal (check pin 29 of CPU for oscillation).
IC-2SAT-Does not run off of external DC.
It is the following:
1) Faulty D9 diode on PRT unit.
2) Faulty DC jack.
Replace faulty D9 diode and/or faulty DC Jack.
IC-2SAT-Doesnt run from internal battery.
Is a faulty D15 diode on the main unit.
replace a faulty D15 diode.
IC-2SAT-Internal or external battery charging problems.
1) Failure on PRT unit.
2) Missing components.
Check for proper voltages on PRT unit. Start at D2 or D8 diodes and troubleshoot from there. Check for missing components under adhesive insulator.
IC-2SAT-No RX/TX at all.
Probably a PLL unlock.
Remove the main unit and check the +5 V, +5S, PLL STB, DATA, CK lines.
Look for damage from a poorly executed out-of-band modification.
IC-2SAT-My IC-2SAT has TX output.
1) Loose antenna connector and/or center conductor jumper wire.
2) Faulty driver and/or PA module.
Check antenna connector for tightness and resolder cracked solder joints as needed. If OK, check the APC and PDI voltages to the power module. If OK check the gain across the PA and driver: driver is approx. 10 dB, PA is approx. 40 dB. There should be very little loss between the power module and antenna jack.
IC-2SAT-No deviation. TX output power is okay.
1) Bad mic element.
2) Faulty flex cable.
3) Broken chip resistor on main board.
If unit works OK with external microphone, check for bad flex cable or internal mic element. If unit does not work with external mic, check for 75 mV p-p audio to mic amp. If present, check for a broken chip resistor on the main board where the shield screws into the upper right corner of the main board (top view).
IC-2SAT-No RX, or low RX sensitivity.
2) Low R+5V.
3) Faulty D7 diode on main unit.
Make sure unit has not been misaligned. Check the R+5V for proper voltage in RX (5 Volts). If OK, check D7 diode on main unit and replace if needed. If unit still does not operate, check the gain of the RF stages:
* RF amp has 18 dB gain
* Mixer 30.875 MHz LO level is very low, about equal to antenna input levels.
* First mixer has approx. 15 dB of gain.
* No loss through the filters.
* Some loss through R6 resistor.
If the above stages are OK, check the detector unit for proper operation.
IC-2SAT-No audio, but it seems to be receiving signals.
1) Bad speaker.
2) Bad flex cable.
3) Burned foil trace.
4) Broken jumpers to VR unit.
Disconnect speaker and check for presence of audio on speaker wires. If present, replace defective speaker. Trace audio at flex cable. Replace flex cable if needed. Check for a burned foil trace at ground of external speaker and repair as needed. This is caused by user plugging in external power to speaker jack. Check for cracked joints at jumpers to VR unit and repair as needed. If all else is OK, check the output through the AF unit: should be 5 Volts p-p at full volume level. If it's not there, check for an output signal on the DET OUT line of the DET unit.
IC-2SAT-Intermittent keypad functions.
Probably cracked solder to the keypad board. Inspect the keypad board solder connection for cracks and repair as needed.
IC-2SAT-Display shifts and rolles.
Probably a faulty CPU clock oscillator. Check the CPU clock oscillator for proper level. Replace crystal if needed.
IC-2SAT-Channel knob shift down or frequency change does not work.
Probably open ground to VR board. Check the VR board for proper ground. Also check for cracked solder joints at VR jumpers.