Minolta Di551 Service Manual page 70

2. Signals
a. Input signals
(1) DM_SIG_EX (TCSB to PRCB)
Output voltage of Dmax detection sensor (PC1)
on TCSB (toner control sensor board)
Reference voltage: 2.5 V
(2) DM_MONI_EX (TCSB to PRCB)
This signal monitors the light reflected by the
drum surface (without toner).
The voltage applied to the Dmax detection LED
is corrected by TNLED_REF so that the output
voltage becomes 1.9 V (calibration).
Reference voltage: 1.9 V
<Timing>
Before Dmax correction
(3) DRUM_JSIG_EX (TCSB to PRCB)
This signal detects a jam caused by paper wrap-
ping around the drum. A jam is detected when
the voltage becomes 4.0 V or more.
(4) TEMP, 3.3V2 (TCSB to PRCB)
Drum temperature detection signal
b. Output signals
(1) DMLED CONT (PRCB to TCSB)
Dmax LED ON/OFF control signal
[L]: LED ON
[H]: LED OFF
(2) TNLED_REF (PRCB to TCSB)
Power supply line for PD1 LED on TCSB.
The voltage is adjusted so that the Dmax MONI
signal becomes 1.9 V.
(3) DJLED_CONT (PRCB to TCSB)
JAM LED ON/OFF control signal
[L]: LED ON
[H]: LED OFF
2-G-5
DEVELOPING UNIT