-----Original Message-----
From: hp_agilent_equipment@...
[mailto:hp_agilent_equipment@...] On Behalf Of xyloeye
Sent: Friday, January 18, 2013 1:52 PM
To: hp_agilent_equipment@...
Subject: [hp_agilent_equipment] Re: HP 3468 DMM battery change
Yeah, I disconnected the battery overnight and shorted the RAM chip Vcc to
gnd to clear any leftover capcitance, etc. That had no effect. I'm kind of
thinking maybe something was on the verge of failure and I pushed it over
the edge. Problem is, even if I narrow it down to a component, all of the
chips are unobtainable now.
Thanks again for your help Jeff.
Ken
--- In hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com> , Jeff Machesky wrote:
You may need to disconnect the battery again to allow the RAM to "zero"
out. Well at least not be in it's present state.
Just a thought,
Jeff
On 1/17/2013 5:16 PM, xyloeye wrote:
Thanks for your reply. You're right, error 1 is calibration RAM. I
tried to calibrate it but since the display is dead, it's hard to do.
When the lead fell off I'm positive it didn't touch anything else. I
just can't figure out how disconnecting the battery would cause a dead
display.
Ken
--- In hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
, "J. L. Trantham" wrote:
I tried to remove and read the contents of the ROM on my 3478A. In the
process, I apparently shorted the 5 V line to ground, which somehow
killed
the contents of the CALRAM. In any event, there was a message about
Calibration. I then replaced the battery and went through the
recalibration
steps and all was well.
According to the manual for the 3468A, Error 1 is 'Calibration RAM
Error'.
Error 2 is 'RAM Error'.
I suspect that the issue is that you lost the RAM contents for the
Calibration RAM. Have you tried to calibrate the unit? Have you
checked
the power supplies?
The alternative is once the lead slipped off, it 'connected' to
something
else and took out something. Was it the + or - lead?
Sounds like you need to go the service manual and start with the
trouble
shooting section, probably Service Group E, and go from there.
Good luck.
Joe
From: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
[mailto:hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
] On Behalf Of xyloeye
Sent: Thursday, January 17, 2013 2:06 PM
To: hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>
Subject: [hp_agilent_equipment] HP 3468 DMM battery change
I'm having some trouble with a battery change in a 3468 DMM. You
would think
I could handle that without incident! I kept 3 volts on the
terminals while
soldering in the new battery but one of the leads slipped off and
there went
the calibration. No problem - I can calibrate it again or so I
thought. The
display flashed "error 1" (ram error)and then went blank. It's been
blank
ever since despite all the resetting procedures I've tried. Could
corrupt
ram cause this? Or is could I have somehow damaged the controller? Any
thoughts would be appreciated.
