[volt-nuts] 3458A AC board

[Randy Scott]

Okay, it arrived a few days ago.  Its pretty banged up on the outside and obviously lived a pretty hard life, but it looks pristine on the inside.

All of the connections look good and the voltages on the inguard power supply are fine.  The only thing that I've found is what appears to be a blown fuse.  There are two soldered-on fuses on the AC board: F701 seems okay (ohm meter sees a short), F702 is open (blown).  Anyone have an idea what this fuse is for?

There are three additional fuses (F001, F002, and F003) on the AC board near a silkscreen label "SPARE FUSES".  Are these truly spares?  Are there any special precautions that I should take before swapping out the bad fuse for one of the spares?

Randy.


--- On Tue, 8/18/09, Mark Sims <holrum at hotmail.com> wrote:

> From: Mark Sims <holrum at hotmail.com>
> Subject: [volt-nuts] 3458A AC board
> To: volt-nuts at febo.com
> Date: Tuesday, August 18, 2009, 12:47 PM
> 
> First thing to do is get the meter in and to try and debug
> the AC board.  It could be something as simple as a
> flakey connection or bad cap/diode/transistor/moon phase
> modulator.
> 
> If you have a (very good) friend with another 3458A it
> would be good to try swapping the AC board to verify that is
> actually the problem.
> 
> Next I would probably get the component level
> documentation  try to debug the unit with that info.
> 
> Only then would I spring for a new AC board (or probably
> just let HP fix the thing).  It would not be good to
> buy a $1000 board that does not fix the problem...  
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