[time-nuts] Questions about HP 5370B
lists at rtty.us
Tue Sep 14 11:40:02 UTC 2010
In an earlier thread on the 5370B checking the voltage out of the regulators was mentioned. If you are going to open the counter up anyway, putting a DVM on them is probably a good idea. They do run hot and some eventually drift way out of spec. Cheap part to replace if it's bad..
On Sep 14, 2010, at 3:12 AM, "Charles P. Steinmetz" <charles_steinmetz at lavabit.com> wrote:
> A friend just received an HP 5370B that was said to be properly working and accurate, and asked my opinion. I'm not familiar with these, so I thought I'd ask the experts. All we've done so far is hook it to a Tbolt that I know is operating properly.
> The 5370B took hours (8 or so, which seems like a long time for a 10811) to drift to a reasonably stable reading, a bit over 100 Hz high (which seems like an awful lot for a 10811, even after a trip across the country ten years since its last calibration). The front-panel oven indicator is off; I did not notice if it was on when we first powered it up. The 5370B reads its own oscillator within spec (< 2 mHz error; spec is +/-5 mHz). We have not opened it to tweak the oscillator (or to verify that the 10811 is, in fact, still present).
> Timing seems to work OK, giving the expected 100 nS and 50 nS figures when I feed the internal oscillator into the start input, tie start to stop (START COM), and switch the trigger phase of the stop channel.
> Finally, the external heatsink (left rear) runs pretty darn hot -- somewhat warmer than you'd really like to leave your hand on, which is WAY warmer than I'd ever design. Concerning (to me), but not completely beyond reason. I suppose it could be normal for these. It didn't burn down or shut off during the 8 hour warmup.
> I appreciate any input from those knowledgeable about the 5370B.
> Thank you,
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