UF-7000, UF-8000, UF-7100, UF-8100 (serv.man2) - Panasonic Fax Service Manual (repair manual). Page 14

14

SEPT 2005

Ver. 2.0

UF-7100/8100

UF-7000/8000

This circuit consists of the DC-DC Converter, which boosts +24V to approx. +5.4kV (constant current 
approx. +300

µA) for the Charge Corona. The nCHGCTL signal controls the charge output. If the signal 

goes Low, the output is turned On.

When the charge circuit is activated (nCHGCTL signal is Low), this circuit is activated and approx. 
+900V is generated on the Grid.

When the charge circuit is activated (nCHGCTL signal is low), this circuit is activated. 
This voltage varies between +100V and +500V in accordance with the PWM (Pulse Width Modulation) 
signal nDB when the signal nDBCH is Low. Also approx. - 150V is generated when signal nDB and 
nDBCH is High.

This circuit consists of the DC-DC Converter, which boosts +24V to -700V ~ -6000V (constant current). 
This current varies between -4µA and -20µA in accordance with the PWM (Pulse Width Modulation) 
signal nTR when the signal nTRCTL is High.

This circuit consists of a DC-DC converter, which boosts +24V to +1500V. 
This voltage is generated when signal nTR is High and nTRCTL is Low.

1. Do not attempt to repair this Power Supply Unit. This Power Supply requires proper calibration after 
    any component replacement. Failure to do so may result in component damage, shock fire or other 
    hazard.
2. High Voltage is present on the PC Board. Use caution when measuring voltage levels.