T- 4.3.0 Pin 6 Less Than 1.0 Volt/Isolate For A 'Shorted' Heater Triac; Solder Side Power Control Board / Triac Wiring View - Fresenius Medical Care 2008K2 Troubleshooting Manual

T- 4.3.0 PIN 6 LESS THAN 1.0 VOLT / ISOLATE FOR A 'SHORTED' HEATER TRIAC
a) Turn the machine OFF and UNPLUG it!
Electrocution hazard if not unplugged!
b) Figure right, lay the Power Supply's rear panel down.
c) Remove the Power Control board from the white plastic
clips to access the board's rear (solder) side.
Set the volt meter to resistance (Ω)!
d)
e) As seen in the Figure below, measure BETWEEN
connectors ST 8 and ST 11.
f) Figure right, reading the meter's numeric AND
units display, TWO (2) possible scenarios:
1) IF MORE THAN 10 Million ohms (10.0
Heater Switch REMAINS ON, see procedure number
2) IF LESS THAN 10 Million ohms (10.0
AND b below:
a) Return NTC #2 to the
b) TWO (2) possible bad components: 1) Bad Triac* OR; 2) Bad Power Control Board.
* To locate the Triac trace the brown and blue wires connected to ST8 and ST11 to it!
CAUTION! The Triac's wires are position sensitive! Plugging into the wrong terminal can
damage the Power Control board or the new Triac
Figure 52 – Solder Side Power Control Board / Triac Wiring
CAUTION!
MΩ
), possibly "OL": IMPORTANT
MΩ
) most likely WAY less (example: 300
st
1
position from the left, "CON-NTC".
2008K/K2 Troubleshooting Guide
P/N 507298 Rev. H
T- 4.4.0 (page 293).
!
ENSURING the
Ω
): See parts a
Page 292