Thermo Scientific SAM12, Manual

Page: 155 / 176

Issue: 1.0 Maintenance and Trouble Shooting
Thermo Fisher Scientific SAM12 User Manual 11-7
protected beneath a metal shield which can be removed by
undoing 4 screws in the top of the cover.
From left to right the cards are organised as:
•
Coincidence detector (1 only)
•
HV and Amplifier for detectors TOP & BOTTOM
Amp 1
•
HV and Amplifier for detectors LEFT & RIGHT
Amp 2
•
HV and Amplifier for detectors FRONT & BACK
Amp 3
Before attempting to remove any FHT681 board, switch the
SAM12 OFF and wait 1 minute for the HV to discharge
before beginning work.
The board mountings are identical. To remove any PCB, first
disconnect the 9-way Dee, then release the MHV coax detector
connector and the BNC coincidence cable for the HV and amps
card or the 9-way Dee and the mating BNC connectors for the
Coincidence card. Carefully prise each pcb from it’s mounting
spacers.
Replacement of any of the boards is the reverse of the removal
procedure. Ensure the colour coded detector cables are
matched to the correct amplifier connector PMT1 or PMT2:
•
LEFT
is Orange /PMT1
RIGHT
is Yellow /
PMT2
•
FRONT
is Red / PMT1
BACK
is Violet / PMT2
•
TOP
is Green / PMT1
BOTTOM
is Blue / PMT2
It is not important which coincidence port is connected to
which amplifier output.
What is important is the identity of the card and the detectors
connected to it!
If any Board is thought to be faulty it should be returned to
Thermo Fisher Scientific’s service department for repair.
NOTE: All cards MUST be linked using the cables originally
supplied
In the event of this part requiring replacement, it must be
replaced with a unit of identical type. When re-connecting the
mains wiring, ensure the mains inlet earth connection is made
securely to the Central Earth Point (CEP). These requirements
Replacement of the FHT681
PCB’s
Removing & Replacing the
Mains Inlet/Filter Assembly