Broken HP 8903E - all lit up, unresponsive

[uoficowboy]

Hi - I have an HP 8903E for the next little while. It'd be nice to fix it. The device is dead - when turned on all LEDs light up ('8's on the 7 segment displays, all LEDs turn on except for the one on the button labeled "s". It does not react to any buttons being pressed.

Anybody have any suggestions as to where to start with this beast?

I measured the supply rails. 5V was dead on, 12V was at 10.8V, -15V and +15V both looked good.

I didn't see schematics anywhere so I was not sure where to go next.

Thanks!!

[vk2hmc]

The 8903E is basically an 8903B minus the sweeper/generator part.
I seem to remember that the 8903E measurement floor has better specification.

However, the good news is the 8903B manual is used to troubleshoot your unit.

The 8903B service manual is here: http://cp.literature.agilent.com/litweb/pdf/08903-90062.pdf
Later revision here: http://cp.literature.agilent.com/litweb/pdf/08903-90062V2.pdf
(! check serial number range for which manual to use)

FWIW, The Cal Manual is here: http://cp.literature.agilent.com/litweb/pdf/08903-90053.pdf


--marki

[macboy]

The 8903E is basically an 8903B minus the sweeper/generator part.
I seem to remember that the 8903E measurement floor has better specification.

However, the good news is the 8903B manual is used to troubleshoot your unit.

The 8903B service manual is here: http://cp.literature.agilent.com/litweb/pdf/08903-90062.pdf
Later revision here: http://cp.literature.agilent.com/litweb/pdf/08903-90062V2.pdf
(! check serial number range for which manual to use)

FWIW, The Cal Manual is here: http://cp.literature.agilent.com/litweb/pdf/08903-90053.pdf


--marki

That's volume 1 and 2, not version 1 and 2. You need both volumes for the complete manual.
There are fairly detailed troubleshooting procedures in the manual. After you find what is dragging down the 12V supply, try them.

[vk2hmc]

I stand corrected, the PDFS are volume one and two of the service manual.
That will teach me to go from memory  


thanks,

--marki

[vk2hmc]

OP should check the serial is covered in the downloadable PDF's.
The more recent instruments are not covered in these manuals.
However there are addendum to bring them up to date.

To reiterate, including Macman's suggestion, Download the service manuals.
Run through the 12v PSU troubleshooting tree and if stuck, post back here


good luck,
--marki