STP 120 Tissue Processor - Service Manual
Page 13
THE PARAFFIN BATHS DO NOT HEAT UP
Possible causes
If one of the paraffin baths does not heat up this may be due to:
•
Faulty paraffin bath:
- Heater
- Thermal circuit breaker
•
Faulty BASCAR V15 circuit board
- Paraffin bath outlet fuses
- The BASCAR V15 circuit board
•
Faulty MICCAR V30 circuit board
•
Ring transformer
$
Before starting the unit using the switch on the rear, make sure that all
the connectors are inserted in the two paraffin baths (or three,
depending on the version), as the unit runs a check for the presence of
these signals on start-up.
Check by
elimination:
Before proceeding with any measurements, determine by elimination
whether the failure is the bath or the control electronics.
If, for example, the paraffin bath that does not heat is No. 12:
1. Turn off the unit
2. Invert the connectors to baths 11 and 12
3. Re-start the unit.
As the paraffin baths are identical, the origin of the failure can be determined
from the result for this test:
•
If the paraffin bath that did not heat with connector 12 does not heat when
connected in position 11, the paraffin bath is very probably faulty
•
If the paraffin bath that did not heat with connector 12 does heat up when
connected in position 11, the error is probably due to the control
electronics
Repairing the
paraffin bath
1. Dismantle the paraffin bath as shown in the figure on page 18
2. Check the continuity of the heater circuit and the thermal circuit breaker.
- If no current can flow through the thermal circuit breaker, replace it.
3. If there is no continuity in the heater circuit, because of the type and
shape of the heater (adhesive), ask your local distributor for a complete
aluminium bath fitted with heater, thermal circuit breaker and
temperature sensor.
Repairing the
control
electronics
1. Checking of the control electronics requires dismantling the lower front
cover as shown in the figures on pages 9 and 10.
2. Reconnect the paraffin baths
3. Connect the unit to the mains power supply
4. Make sure that the output voltage of the terminals on the BASCAR V15
circuit board is 24 V DC:
Outputs for the
heaters
Locating the input terminals of the circuit board and the output to the paraffin
baths, and the fuses for the heaters on the BASCAR V15 circuit board.
