HYDRA
Service Manual
5A-20
If the instrument powers up and displays ’boot,’ it is likely that one of the memory test
errors (Errors 1 through 3) was detected. To determine what the error status was, connect
a terminal or computer to the RS-232 interface (19200 baud, 8 data bits, no parity).
Assuming that the RS-232 interface is functional, send a carriage return or line feed
character to the instrument, and it should send back a prompt that shows a number
followed by a ’>’ character. The number is interpreted in the same way as the responses
for the *TST?and POWERUP? commands; refer to *TST? in Section 4 of the Hydra
Data Bucket Users Manual. For example, a ’4>’ prompt indicates that the test of the
NVRAM (A1U20 and A1U24) failed and the instrument was not able to safely power-up
and operate.
Now send a ’t’ character followed by a carriage return to the instrument to request a retest
of the firmware stored in Flash Memory. If both the boot firmware and the instrument
firmware checksums are correct, the response will be as follows:
Boot image OK
Hydra image OK
0>
If the boot firmware checksum is not correct, the message "Bad boot image -- use at own
risk!" might be seen. The code that must be executed to generate this message is part of
the boot firmware that is bad, so there is no guarantee that this message will be seen.
If the instrument firmware checksum is not correct, one of the following error messages
may be seen:
Bad rom pointer
"Invalid pointer to checksum structure"
Bad checksum pointer
"Invalid pointer to instrument checksum"
Bad checksum
"Incorrect instrument checksum"
Invalid instrument firmware may be corrected by using a personal computer to load new
instrument firmware into the Hydra Databucket. To do this see the section entitled
"Updating the 2635A Instrument Firmware" in Section 4 of this manual.
If the NVRAM (A1U20 and A1U24) do not operate correctly, the problem must be
corrected before new instrument firmware may be loaded or the instrument can power up
completely. Use an oscilloscope to check the activity of the address, data, and control
signals to the NVRAM devices (A1U14 and A1U16). It may be necessary to continually
reset (power on) the instrument to check these lines, since the activity probably halts
quickly when the instrument software goes awry. To check the NVRAM control signals,
verify that A1U1-127 is going low, propogating through A1U26, and also appearing on
pins A1U20-22 and A1U24-22 of the NVRAM devices. Verify that RDU* (A1U11-14
and A1U24-24) goes low when A1U1-127 is low. Verify that RDL* (A1U11-19 and
A1U20-24) goes low when A1U1-127 is low. If all this is true, the problem is with the
NVRAM itself or there is a fault in the address/data lines from the MC68302
Microprocessor. It may also be useful to check signal continuity by using a DMM with
the instrument power off. Verify also that pin 30 on A1U24 and A1U20 is pulled up to
approximately 5.0 volts dc by resistor A1R45.
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...
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...
