Fresenius Medical Care 2008K Troubleshooting Manual page 256

HEATER RELAY- 2.0.0 CHECK DIODE 17
a) Turn the power off and unplug the machine. Caution! High Voltage if not unplugged!
b) Referring to Figure 111
power control board.
c) Unplug the X2 ribbon cable from the top of the power control board.
d) A bad diode 17 will damage the power logic board. Check its resistance ( )*
(see Figure 111) by placing the meter leads on either side of it.
e) Is the meter's numeric AND units display indicating a resistance between 500
and 1500 (or between 0.50 K and 1.5 K )?
Yes The diode is okay. See procedure number
No Replace the power control board (or diode 17 (1N914B)). The power logic board is probably
bad also (see
to HEATER RELAY- 2.0.1
* NOTE: The meter's diode check function will not work because the diode is 'in circuit'
HEATER RELAY- 2.0.1 CHECK THE POWER LOGIC BOARD
a) Reconnect the X2 cable.
b) Swap in a known good power logic board (see
c) Place the machine into Dialysis program. Does the Heater Relay alarm reoccur?
Yes Two possibilities: 1) Bad power logic board AND power control board (diode 17); 2) Bad
function board.
No Problem solved. The previous power logic board was bad (transistor T5).
Figure 108 – Power Control Board (Diode 17)
(page 254), open the power supply to access the front (component) side of the
Figure 4A and NOTE B, page 8). After board or diode replacements continue
(page 254).
Fresenius 2008K Troubleshooting Guide
P/N 507298 Rev. B (Draft 1)
HEATER RELAY- 2.0.1
Figure 4A and NOTE B, page 8).
Section 23 – Heat Relay Test Fail
(page 254).
Page 254