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HYDRA
Service Manual
2-8
2-24. Power Supply Circuit Description
The Hydra power supply consists of three major sections:
•
Raw DC Supply
The raw dc supply converts line voltage (90V to 264V ac) to a dcoutput of 7.5V to
35V.
•
5V Switcher Supply
The 5V switching supply regulates the 7.5 to 35V dc input to anominal 5.1V ±0.25V
dc (VCC).
•
Inverter
Using the 5V switching supply output, the inverter generates the -30Vdc, -5V dc,
and 5.4V ac supply levels needed for thevacuum-fluorescent display and the RS-232
Interface. The inverteralso provides is5.3V (VDD), +5.6V (VDDR), and -
5.4V (VSS)outputs for the inguard circuitry.
2-25. Raw DC Supply
The raw dc supply circuitry receives input from power transformer T401, which operates
on an input ranging from 90V to 264V ac. The power transformer is energized whenever
the power cord is plugged into the ac line; there is no on/off switch on the primary side
of the transformer. The transformer has an internal 275V ac metal-oxide varistor (MOV)
to clamp line transients. The MOV normally acts as an open circuit. When the peak
voltage exceeds approximately 400V, the line impedance in series with the line fuse
limits transients to approximately 450V. All line voltages use a slow blow 0.125 A,
250V fuse.
On the secondary side of the transformer, rectifiers A1CR2, A1CR3, and capacitor A1C7
rectify and filter the output. When it is ON, switch A1S1 (the front panel POWER
switch) connects the output of the rectifiers to the filter capacitor and the rest of the
instrument. Depending on line voltage, the output of the rectifiers is between 7.5 and
35V dc. Capacitor A1C2 helps to meet electromagnetic interference (EMI) and
electromagnetic compatibility (EMC) requirements.
When external dc power is used, the power switch connects the external dc source to
power the instrument. The external dc input uses thermistor A1RT1 (for overcurrent
protection) and diode A1CR1 (for reverse input voltage protection.) Capacitor A1C59
helps meet EMI/EMC requirements. Resistor A1R48, capacitors A1C2 and A1C39 also
ensure that the instrument meets EMI/EMC performance requirements.
2-26. Auxiliary 6V Supply
Three-terminal regulator A1U19, voltage-setting resistors A1R44 and A1R46, and
capacitor A1C34 make up the auxiliary 6-volt supply. This supply is used for the inverter
oscillator, inverter driver, and the power fail detection circuits.
2-27. 5V
Switcher
The 5V switcher supply uses a switcher supply controller/switch device A1U9 and
related circuitry.The 7.5V dc to35V dc input is regulated to 5.1V dc (VCC) through
pulse-width modulation at a nominal switching frequency of 100 kHz.
The output voltage of the switcher supply is controlled by varying the duty cycle (ON
time) of the switching transistor in the controller/switch device A1U9. A1U9 contains
the supply reference, oscillator, switch transistor, pulse-width modulator comparator,
switch drive circuit, current-limit comparator, current-limit reference, and thermal limit.
Содержание 2620A
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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...
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Страница 172: ...HYDRA Service Manual 5 2 5 28 Failure to Detect Memory PCA 5 29 5 29 Failure to Store Data 5 29...
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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...
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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...
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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...