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The Advanced

Model 3250/4250 Service Manual

SHOULD NOT BE RECONNECTED

WITH INSTRUMENT POWER ON, OR

DAMAGE TO THE INSTRUMENT MAY

RESULT.

The printer control board (325421) translates

the data from the application board (PDCB605)

into control signals for the print head thermal

elements and drive motor (325404). This board

also contains a factory-set configuration DIP

switch (DS1) and jumper (JP1).

On models equipped with cable (325033), a

compatible version of main board set (325605)

and a properly configured printer interface

board (PCB402), diagnostic LEDs, and a test

switch are available in the lower right corner

of the larger board (PCB605). D19 is a red

LED that will indicate the printer door/platen

interface is not closed or, if blinking, one of

several printer errors have occurred, requiring

factory assistance. D20 is a yellow LED that

will indicate the paper is out or not detected

when the door is closed. SW1 is a momentary

switch that will cause the paper to advance

when pressed or, if held down while main

power is switched on, will place the printer

into self-test mode.

The serial number suffix (referred to in this manual simply as the suffix) indicates the revision of the

instrument. The chart below lists the major changes made at each revision of the 3250 Osmometer and

4250 Cryoscope.

Model 3250

Osmometer Description

Serial Suffix ‘A’ Original model released.

January 2004

Serial Suffix ‘B’ Base chassis and cover re-

May 2007 designed.

Serial Suffix ‘C’ Up/Down relay PC boards re-

October 2007 designed into a single RoHS-

compliant PC board.

Serial Suffix ‘D’ **MAJOR REVISION**

September 2009 AC head motor and supporting

components replaced with a DC

stepper motor, multi-driver PC

board and power supply, Seiko

thermal printer assembly with

thread-through paper loading and

supporting components replaced

with a Citizen thermal printer

assembly with easy-load paper

Serial Suffix ‘E’ Application board redesigned to

October 2010 power display and keypad LEDs

from VCC +5 VDC line. Main

harness redesigned.

Design Changes

Model 4250

Cryoscope Description