Power Supply System Troubleshooting; Testing The Power Supply - Filtec FT-50c Service And Technical Reference Manual

Power Supply System Troubleshooting

A B C D
Test Output
Reference
Point VDC
1 TP-6 +5
2 TP-2 +12
3 TP-4 +22
4 TP-5 12
5 J-1 +1000*
6 Q8-3‡ -5
7 P4-2 +60
8 TP-3
Industrial Dynamics Company, Ltd. Document 40255-0600
Power supply instability and failures account for many malfunc-
tions. We recommended testing the power supply voltages as a
starting point when troubleshooting. You need a digital voltmeter
with an impedance of at least 20,000 ohms per volt to perform
these procedures.

Testing the Power Supply

1. Remove the FT-50's cover to access the power supply inside.
2. Using test point TP3 as ground, test all voltages at the appro-
priate test points.
7
Figure8-1. Power Supply Circuit Board test points.
Range Xfmr
VDC Winding
5.0/5.2 28 VAC
11.5/12.5 28 VAC
18.0/22.0 28 VAC
11.5/12.5 28 VAC
800/1200 28 VAC
4.9/5.1 28 VAC
50/60 36 VAC
Chapter 8: Diagnostic and Repair Procedures
6
Source
Description
Supply
+V Processor Logic, Scintillation Detector
+V Scintillation Tube Pulse Preamplifier,
Control Panel, Serial Port Drivers
+V Sensor Emitters/Amplifiers, Input
Comparators
Unreg Control Panel, Serial Port Drivers
+22VDC Scintillation Detector
-12VDC RS232/RS422 Drivers
Unreg Rejector Driver, Rejector
Ground
5
4
3
2
1
8
8-15