Technical information

When a Printhead or the printer’s Power Supply is replaced, the Printhead
Voltage must be adjusted for the proper value. This adjustment establishes the
voltage applied to the print elements during the printing process. When
adjustment is necessary, follow the procedure below.
CAUTION: This voltage adjustment is critical to the life of the Printhead.
DO NOT use this adjustment in an attempt to increase the Printing Darkness.
1. Calculate the proper Printhead Voltage using the formula or chart below.
In the formula, Resistance is the Print Element average resistance value as
indicated on a label on the Printhead. The label can be seen by releasing the
Printhead latch, moving the ribbon (if any) to the side and looking up at the
underside of the Printhead.
2. Remove the three mounting screws and the Electronics Side Panel to
provide access to the Main Logic Board.
3. Attach a voltmeter between test point TP8 and Ground on the Main Logic
Board. TP8 is located close to J3, the Printhead Connector.
4. Turn the printer ON. See Figure 5.26 for the location of Head Voltage
Potentiometer, RV2. RV2 is located on the Power Supply Board, just to the right
of the Main Logic/Power Supply Board’s mating connector, and is accessible
through the opening at the base of the printer. Adjust the Head Voltage Pot (RV2)
so the voltmeter reading matches the value determined in Step 1.
Voltage Table: 8 dot/mm Printheads V = 0.479 + sqrt(0.64 *Resistance)
Voltage Table: 6 dot/mm Printheads V = 0.479 + sqrt(0.978*Resistance)
315 18.0
320 18.2
325 18.3
330 18.4
335 18.6
340 18.7
345 18.8
350 19.0
355 19.1
360 19.2
365 19.4
370 19.5
375 19.6
380 19.8
385 19.9
390 20.0
395 20.1
400 20.3
405 20.4
410 20.5
535 19.0
540 19.1
545 19.2
550 19.2
555 19.3
560 19.4
565 19.5
570 19.6
575 19.7
580 19.7
585 19.8
590 19.9
595 20.0
600 20.1
605 20.2
610 20.2
615 20.3
620 20.4
625 20.5
630 20.6
635 20.6
640 20.7
645 20.8
650 20.9
655 21.0
660 21.0
665 21.1
670 21.2
675 21.3
680 21.3
685 21.4
690 21.5
Page 5-20 44868L