[time-nuts] new request for 3458A info

[Dick Moore]

On Aug 2, 2009, at 5:00 AM, time-nuts-request at febo.com wrote:
>
> Message: 4
> Date: Sun, 02 Aug 2009 03:00:06 +0200
> From: "Dr. Frank Stellmach" <drfrank.stellmach at freenet.de>
> Subject: [time-nuts] 3458A info
> To: time-nuts at febo.com
> Message-ID: <4A74E516.5020202 at freenet.de>
> Content-Type: text/plain; charset=ISO-8859-15; format=flowed
>
> Dick,
>
> did you already try an ACAL DCV, or ACAL ALL from the front panel?
>
> Maybe the false cal constants will be set correctly.
>
> In the calibration manual, its explained, which constants are set by
> atocal (and cured), and which one are set by basic calibration,
> requiring external standards (10 volt, 10kohm).
> I think, DAC Vos and 10V gain are set by ACAL.
>
> Frank

Yes, tried all that. Last night I gave up and opened the box, which I  
had been reluctant to do -- DC board had burned components right in  
the center. There are 2 unrecognizable ICs and a handful of resistors,  
etc, and a badly charred board. Probably unrepairable. Have no idea  
what could have happened to make it so bad without also killing the  
power supplies, which are AOK. Shouldn't have been anything on the  
input, which is protected against over-voltage/-current. Too bad.

Thanks for all the advice and tips.

Dick Moore