[time-nuts] HP quality

EB4APL eb4apl at cembreros.jazztel.es
Sun Sep 11 22:49:50 UTC 2011

I got one more example of loose QA in an item fully on topic:  I bought 
a Rb oscillator, a FRS-C and when I opened the case just for curiosity 
found one of the connector pins without any trace of solder on it, it 
was just making contact with the PCB hole.  It carried the in-lock 
signal and I like to think that probably this unit showed intermittent 
fails and was replaced with low hours.

Ignacio EB4APL

On 11/09/2011 10:32, Geoff Blake wrote:
>>> That is not a unique incident.
>>> I'm interested in LASER Interferometry. Attached is a pic I took of an HP
>>> 5529A LASER head.
>>> (Aside: If anybody is interested, there is a Yahoo Group for LASER
>>> Interferometer fans)
>>> Note the two leads to CR5 near the top, center of the pic. They go to a
>>> feedback photocell and obviously have never been trimmed or soldered.
>>> The unit ran fine that for several months before suddenly failing.
>>> Soldering the leads fixed the LASER head.
>> It was not always this way.  Today I stumbled on a 1965 HP 738BR
>> Voltmeter Calibrator at my favorite surplus electronics store.  I
>> offered $20.00 and it was accepted.
>> This unit is based on vacuum tubes!  I got it home, plugged it in, and
>> it is still in spec on the DC range.  The AC part is not working - I
>> suspect the small incandescent lamp that stabilizes the oscillator.
>> I may end up junking the vacuum tube half.  The other part of the
>> instrument, in a separate compartment, has a precision 40 step
>> attenuator with a 10^6 / 1 range (300 Volts to 300 uVolts) which I will
>> certainly keep.
>> Best regards,
> No please don't junk the valve part, it would be be waste of a lovely
> instrument.
> However that's not the topic.
> I first met a HP 3582 LF SA when it came into the cal lab from a
> remote site, just out of warranty. Apart from being out of cal, the
> was a brief comment, "intermittent channel 1". We had not seen one
> before and being the "guv" I got to play first.
> Yes there was an intermittent fault and it seemed vibration sensitive.
> After I had figured how to drive it (what's a FFT analyser - what's a
> FFT? but I was young then.) I could confirm the fault and I had even
> found the diagnostics in the manual.
> Running diagnostic 1 I determined that the fault was in IC1 or IC3 and
> using diagnostic 2 I narrowed it down to IC1 or IC2, so suspecting a
> loose IC1 I put a rather large thumb and pressed - the fault
> disappeared  Remove thumb and it was back!
> In for a penny, in for a pound, I pulled the chip and yes, even I
> could spot the doubled up pin, so I gently straightened it and that
> was the cure. Later I was told that the fault was there since
> delivery, but they could not afford to spare it at the the time.
> (Please note the (IC) names have have been changed to protect my memory.)
> Geoff G8GNZ

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