Service manual

Diagrams 71
Table 6-3. Test Points (continued)
TEST POINT No. & Loc. Signal Tested Measurement and Conditions
A4 AC Input Board
Connect meter between TP 9 and 10, or 9 and 11, or 10 and 11, and measure approximately 220VAC or 440VAC.
J418-1/J417-7
AC Mains Voltage
J418-2/J417-8
AC Mains Voltage
J418-3/J417-9
AC Mains Voltage
K402 coil
24VDC Coil Voltage Turns on PS, and after power-on initialization
test, reads approximately 24VDC.
A5 DC Rail Board
J430-1 (+) to J430-2 (-)
Rail #1 Voltage Measure approximately 290VDC
J431-1 (+) to J431-2 (-)
Rail #2 Voltage Measure approximately 290VDC
A6 Bias Board
J801-4 to J801-5
GPIB 5V Bias
+15 ± 0.9V measure approx. 11VAC
J801-1 (+) to J801-2 (-)
Fan voltage Measure 24Vdc
J827-1 (+) to J827-2 (-)
Inrush relay coil Measure 24Vdc
J827-1 (+) to J827-3 (-)
Rail relay coil Measure 24Vdc after power-on initialization test.
J816-3 to J816-4
24V Primary Measure approximately 34VAC
R813
-15V bias -15V
R806
+ 5V bias +5V
R812
+15V bias +15V
A3 FET Board
NOTE: Because test points on the FET board are not accessible when the board is installed; troubleshooting must be
performed with the board removed from the power supply (refer to the disassembly procedures at the back of chapter 3).
1. Turn off the power supply and remove the A3 FET Board with its heat sink assembly.
2. Short the collectors of Q251 and Q253 or Q351 and Q353 by connecting the collector (case) of each transistor to
common ( E507) .
3. Connect waveform generator to J200-1 and J200-2.
4. Set generator to produce a 20 kHz, 20V p-p triangular waveform
5. Connect 15V from an external supply to E206 or E306 (positive) and E207 or E307 (common).
E207/E307
Secondary common (Sheet 1,2) Connect meter or scope common here. Make
measurements at test points 27 through 35.
U203-1/U303-1
Bias voltage (Sheet 1, 2) +5V
U204-1/U304-1
Bias trip point (Sheet 1, 2) Voltage goes from low (0V) to high (5V) at an
input of ≈ 12V; and from high to low at ≈ 13V.
U201-1/U301-1
Drive 1 waveform (Sheet 1) See Figure 6-1
U201-12/U301-12
Drive 2 waveform (Sheet 2) See Figure 6-1
U201-10/U301-10
Drive pulses (Sheet 1, 2) See Figure 6-1
U201-7/U301-7
Drive pulses (Sheet 1, 2) See Figure 6-1
U202-1/U302-1
Drive pulses (Sheet 1, 2) See Figure 6-1
U202-7/U302-7
Drive pulses (Sheet 1, 2) See Figure 6-1
U205-2
VREF voltage (Sheet 1)
≈ 1.7V