[time-nuts] 5370A

Roy Phillips phill.r1 at btinternet.com
Sat Oct 10 16:27:16 UTC 2009

Thank you - that's good news re temperature - I will check the transformer 
for loose laminations. I am collecting the various information from other's 
regarding calibration/ performance.

----- Original Message ----- 
From: "Greg Burnett" <gbusg at comcast.net>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Saturday, October 10, 2009 4:24 PM
Subject: Re: [time-nuts] 5370A

> Roy,
> The HP 5370A rear mounted heat-sink typically heats up to around 61 
> degrees
> C. This is very hot to the touch, so I suspect your unit's temperature is
> normal (unless it's running way hotter than 61 degrees C).
> The buzzing transformer might just be due to loose, vibrating laminations.
> You might try tightening the transformer's bolts to see if that reduces 
> the
> buzz?
> Best,
> Greg
> P.S. I agree that the rear mounted heat sinks of most other HP equipment 
> run
> significantly cooler. The models that run so hot to the touch are the
> 5370A/B, 5359A, and many of the legacy HP pulse generators (from Boblingen
> Division).
> ----- Original Message ----- 
> From: "Roy Phillips" <phill.r1 at btinternet.com>
> To: "Discussion of precise time and frequency measurement"
> <time-nuts at febo.com>
> Sent: Saturday, October 10, 2009 4:08 AM
> Subject: Re: [time-nuts] 5370A
> Hi Joe
> I have a similar problem so I would be pleased to hear from you with any
> useful information. The basic problem with mine is that the power supply 
> is
> suspect - it works, but there is excessive heat, much greater than any 
> other
> HP instrument that I have, from the rear mounted heat-sink, this is too 
> hot
> to hold your hand on ! There is also a very obvious buzz from the power
> transformer, even when it is on "stand-by" - so I guess at worst it could 
> be
> shorted turns in the power transformer, or probably better, a faulty 
> bridge
> rectifier,or one or more of the large reservoir caps -  this an early 
> model
> (1984), so perhaps it is to be suspected. I also think the performance is
> not to specification, but I will check-out the perceived problem with PSU
> before I investigate this matter.  I am just about to start the
> investigation of the prime problem.
> Roy
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