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HYDRA
Service Manual
5-14
Table 5-3. Power Supply Troubleshooting Guide (cont)
Symptom
Fault
A1U18 hot.
Shorted A1C32
A1U18 oscillates.
Open A1C32.
A1U19 oscillates.
Open A1C34.
A1U19 very hot.
- Shorted A1U22 (VCC to VSS).
- Shorted A1U23 (VCC to VSS).
A1U19 hot.
Shorted A1C34.
Check that the inguard Microcontroller A3U9 RESET* line is de-asserted. Check VDD
at A3TP1, referenced to A3TP9.
Check that the microcontroller crystal oscillator is running. When measured with a high
input impedance oscilloscope or timer/counter, the oscillator output at A3TP10 should
be a 3.6864-MHz sine wave (271.3 ns period), and the divided-down E clock output at
A3U9 pin 68 should be a 921.6 kHz-square wave (1.085
µ
s period).
Check outguard to inguard communication. Setup an input channel and enable monitor
measurements on that channel, causing the outguard to transmit to the inguard
approximately every 10 seconds.
On the Main PCA, look for outguard-to-inguard communication (5.1V (VCC) to near 0V
pulses) at A1TP15, referenced to A1TP1. On the A/D Converter PCA, check for 5.35V
(VDD) to near 0V pulses at A3TP8, referenced to A3TP9.
At the start of outguard-to-inguard communication, the A/D Microcontroller (A3U9)
should be RESET. Check for this reset pulse (5.35V (VDD) to near 0V, lasting
approximately 1-ms) on A3TP1 with respect to A3TP9.
Check for the following inguard-to-outguard communication activity:
PCA
Test Point
To
Pulses
A/D Converter
Main
A3TP7
A1TP8
A3TP9
A1TP1
5.55V (VDDR) to 0.7V
0V dc to 5.1V (VCC)
Lack of outguard-to-inguard communication activity may be due to improper operation
of circuit elements other than A3U9. Using a high input impedance oscilloscope or
timer/counter, check for proper Analog Processor (A3U8) crystal oscillator operation. A
3.84-MHz sine wave (260 ns period) should be present at A3U8 pin 37 with respect to
A3TP9.
Check the A/D Converter voltage reference:
A3TP12 to A3TP11 (across A3C12) = +1.05V (+0.10V, -0.02V)
Setup the instrument to measure ohms on the 300
Ω
range. Monitor ohms on a channel
with an input of approximately 270
Ω
. Check that the Analog Processor IC (A3U8) is
making A/D conversions. The integrator output waveform at A3TP13 (referenced to
A3TP9) should resemble the waveform shown in Figure 5-6.
Check for channel relay operation by setting up a channel and selecting and de-selecting
monitor measurement mode. One or more relays should click each time the monitor
button is pressed or channels are changed.
In general, check that the relays are getting the proper drive pulse signals for specific
functions and channels and that they are in the correct position.
Содержание 2620A
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Страница 18: ...HYDRA Service Manual 1 2...
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Страница 126: ...HYDRA Service Manual 3 2 3 30 Install the Handle and Mounting Brackets 3 15 3 31 Install the Instrument Case 3 15...
Страница 134: ...HYDRA Service Manual 3 10 Q Y U P J O A D B C V W G K L M E T X H I s25f eps Figure 3 5 2635A Assembly Details...
Страница 140: ...HYDRA Service Manual 3 16...
Страница 172: ...HYDRA Service Manual 5 2 5 28 Failure to Detect Memory PCA 5 29 5 29 Failure to Store Data 5 29...
Страница 234: ...HYDRA Service Manual 5A 34...
Страница 236: ...HYDRA Service Manual 6 2...
Страница 244: ...HYDRA Service Manual 6 10 A4 MP3 A4 H65 MP2 MP66 MP67 2620A 100 s58f eps Figure 6 1 2620A 2625A Final Assembly cont...
Страница 250: ...HYDRA Service Manual 6 16 A4 MP3 A4 H65 MP2 MP66 MP67 2620A 100 s62f eps Figure 6 2 2635A Final Assembly cont...
Страница 254: ...HYDRA Service Manual 6 20 2620A 1601 s63f eps Figure 6 3 2620A 2625A A1 Main PCA...
Страница 258: ...HYDRA Service Manual 6 24 2635A 1601 s64f eps Figure 6 4 2635A A1 Main PCA...
Страница 260: ...HYDRA Service Manual 6 26 2620A 4002 CKT 1 CKT 2 s65f eps Figure 6 5 A2 Display PCA...
Страница 265: ...List of Replaceable Parts Service Centers 6 6 31 2620A 1604 s67f eps Figure 6 7 A4 Analog Input PCA...
Страница 267: ...List of Replaceable Parts Service Centers 6 6 33 2620A 1605 s68f eps Figure 6 8 A5 IEEE 488 Interface PCA Option 05...
Страница 269: ...List of Replaceable Parts Service Centers 6 6 35 2625A 1606 s69f eps Figure 6 9 2625A A6 Memory PCA...
Страница 271: ...List of Replaceable Parts Service Centers 6 6 37 2635A 1606 s70f eps Figure 6 10 2635A A6 Memory Card I F PCA...
Страница 272: ...HYDRA Service Manual 6 38...
Страница 274: ...HYDRA Service Manual 7 2...
Страница 282: ...HYDRA Service Manual 7 10...
Страница 284: ...HYDRA Service Manual 8 2...
Страница 285: ...Schematic Diagrams 8 8 3 Figure 8 1 A1 Main PCA 2620A 2625A 2620A 1601 s88f eps...
Страница 288: ...Schematic Diagrams 8 8 6 Figure 8 1 A1 Main PCA 2620A 2625A cont 2620A 1001 3 of 4 s73f eps...
Страница 292: ...Schematic Diagrams 8 8 10 2635A 1001 2 of 5 Figure 8 2 A1 Main PCA 2635A cont s76f eps...
Страница 293: ...Schematic Diagrams 8 8 11 2635A 1001 3 of 5 Figure 8 2 A1 Main PCA 2635A cont s77f eps...
Страница 296: ...Schematic Diagrams 8 8 14 2620A 4002 CKT 1 CKT 2 Figure 8 3 A2 Display PCA s90f eps...
Страница 300: ...Schematic Diagrams 8 8 18 2620A 1003 2 of 3 Figure 8 4 A3 A D Converter PCA cont s82c eps...
Страница 301: ...Schematic Diagrams 8 8 19 2620A 1003 3 of 3 Figure 8 4 A3 A D Converter PCA cont s83c eps...
Страница 302: ...Schematic Diagrams 8 8 20 2620A 1604 Figure 8 5 A4 Analog Input PCA s92f eps...
Страница 304: ...Schematic Diagrams 8 8 22 2620A 1605 Figure 8 6 A5 IEEE 488 Interface PCA 2620A Only s93f eps...
Страница 306: ...Schematic Diagrams 8 8 24 2625A 1606 Figure 8 7 A6 Memory PCA 2625A s94f eps...
Страница 310: ...Schematic Diagrams 8 8 28...