[time-nuts] 5370A

[Joseph Gray]

John,

Thanks for the good advice. I definitely need to pull the front panel
to replace the flakey BNC. After that, I'll do what I can with the
A3/A4 adjustments. I just took another look at what I was doing last
night and the two input channels do need adjusting. The B channel is
worse.

I have a few other things that need to get done this weekend, so the
5370A will be on the bench for a little while. I'll get back to you
after I get the inputs adjusted.

Joe Gray
KA5ZEC

On Sat, Oct 10, 2009 at 6:07 PM, John Miles <jmiles at pop.net> wrote:
>
>> I plan on doing the A3/A4 adjustments. I just don't know where I'm
>> going to get a pulse generator or the fancy scope with the 1GHz
>> sampling plugin. Not the type of equipment on your average test bench.
>
> You won't need any exotic gear for the DAC voltage adjustments or the A3/A4
> input assembly adjustments, which is what comes first in the manual.  As I
> recall the scope is only used for symmetry adjustments in that section of
> the manual, so the risetime is not all that important as long as it will
> give you a stable trigger.
>
> You can skip the pulse-response adjustment unless you have reason to suspect
> a specific problem.  Watch for the pots that this step calls for, and don't
> center them at the beginning of the alignment process when the manual tells
> you to.  As I recall there are various typos in the manual, so watch out for
> that too. :)  In general, the 5370 alignment instructions are crap by HP's
> usual standards, so *be careful*.  Read and understand everything before
> doing anything.
>
> The A18 DAC adjustments should actually be done first IMHO.  Don't worry if
> the test limit voltages are not achievable -- they aren't, on any 'B' model
> I've ever aligned -- as long as they are symmetrical.  For example, +/- 1.9
> volts is OK, instead of the +/- 2.2 volts called for in some versions of the
> manual.
>
> If you don't have an 8082A pulse generator and a fast scope, you will want
> to stop there, and not mess with A19/A20.  Likewise you probably do not need
> to align the A21 multiplier (which is the only step that requires a spectrum
> analyzer) if you don't have reason to suspect a problem with it.  I believe
> some people have found that the standard-deviation floor can be improved by
> realigning A21 but I haven't done that myself.
>
> The instructions that call for a 1 GHz sampling scope don't actually need a
> sampling scope; they can be followed with a Tek 2467-class scope as well.
> But again, the front-end work should be doable with a good 100 MHz+ model,
> and the rest should not be attempted without an 8082A pulse generator.
>
> The nasty thing about aligning a 5370 is the fact that the steps generally
> begin with setting all the pots and trimmers to a fixed position, usually
> midpoint.  Ordinarily it's best not to disturb the alignment of a stage
> that's already in tolerance, but they don't give you that option with the
> 5370, and you may get pretty far before you discover that your test
> equipment such as the pulse generator is not up to the task.  When they call
> for an 8082A in the A19/A20 section, they *mean* an 8082A, and you don't
> want to get halfway into that procedure before you realize that.
>
> -- john, KE5FX
>
>
>
>
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