If within your technical abilities, check the internal power supply voltages with a meter. You should be able to find a PRO-2006 service manual online to assist if you don't have one.
The PRO-2006 converts 120VAC to 12VDC (unless operating directly from an external 12VDC source, as others have recommended), and then converts the 12VDC to 5 VDC and 8.3 VDC via a pair of voltage regulators (IC8 and Q32 respectively) to feed its circuits. It subsequently converts the 5VDC to 30VDC via an inverter circuit (T9, Q24, Q25) for the PLL board.
Basic tests:
There is one additional CMOS 5VDC regulator (IC9) which provides memory backup power on the CPU5V line even when the scanner is turned off (or unplugged, assuming the battery is installed). It is reportedly susceptible to failure, but I'm not sure whether or not that would cause the entire scanner to stop working. If verifying this voltage, take anti-static precautions, use a high impedance voltmeter, and be careful to avoid short circuits to prevent component damage.
As a hail Mary, you can allow the radio to sit overnight with power and battery removed, then reconnect both and turn the radio back on while holding down the reset button for several seconds.
The three components in your photo (C152, C151, L56) appear to be in the IF section and not likely related to your problem. They are connected to Q14, which is identified in the block diagram as a noise amplifier.
Good luck. I still use my PRO-2006 and hope you can revive yours.
The PRO-2006 converts 120VAC to 12VDC (unless operating directly from an external 12VDC source, as others have recommended), and then converts the 12VDC to 5 VDC and 8.3 VDC via a pair of voltage regulators (IC8 and Q32 respectively) to feed its circuits. It subsequently converts the 5VDC to 30VDC via an inverter circuit (T9, Q24, Q25) for the PLL board.
Basic tests:
- The audio amplifier is fed directly by 12VDC. You should hear a pop from the speaker when the radio is turned on and a very slight hiss while powered up, but a loud hum could indicate failure of the main AC filtering capacitor.
- The display illumination is fed by 5VDC. Since yours works, it would suggest that the 5VDC regulator is healthy
- If the LED above your Sound Squelch button works, it would suggest that your 8.3VDC regulator is healthy.
There is one additional CMOS 5VDC regulator (IC9) which provides memory backup power on the CPU5V line even when the scanner is turned off (or unplugged, assuming the battery is installed). It is reportedly susceptible to failure, but I'm not sure whether or not that would cause the entire scanner to stop working. If verifying this voltage, take anti-static precautions, use a high impedance voltmeter, and be careful to avoid short circuits to prevent component damage.
As a hail Mary, you can allow the radio to sit overnight with power and battery removed, then reconnect both and turn the radio back on while holding down the reset button for several seconds.
The three components in your photo (C152, C151, L56) appear to be in the IF section and not likely related to your problem. They are connected to Q14, which is identified in the block diagram as a noise amplifier.
Good luck. I still use my PRO-2006 and hope you can revive yours.