Re: My 2465B has arrived + A5 Board leaky caps cleanup


Chuck as usual your explanations are outstanding. After reading them, just a few short extra questions/comments, bellow.

On Wed, Oct 31, 2018 at 09:49 PM, Chuck Harris wrote:
The design of the front panel is such that all of
the displays states are in registers that get strobed
whenever anything is changed on the front panel. That
shows up as a brief flash of all lights.

The 2465B uses 74F logic for those registers, the older
2465 used 74LS logic, and fairly dim LED's. The blink
is scarcely noticeable with the older 2465. The 2465B
uses much brighter LED's, and the blink is quite apparent.
I assumed that it was normal, but I was surprised to see the effect as it was never evident on any of the videos I'd seen before.

With 350MHz bandwidth comes a lot of ambient noise. Cut
the bandwidth, and you will cut the noise. That is why
the scope has the 20MHz bandwidth limit switch on the
front panel.
So it is normal to see some fuzziness on the traces at full bandwidth? I really have to go through this again, as I seem to remember the amount of fuzziness varied somewhat depending on the time/div setting, not sure that would be normal. I am still awaiting for the Mouser parts for the A5 board to arrive, and will confirm that once I have to put the scope back on the bench to work on replacing those parts.

The 2465B is not a frequency counter, and the A5 board's
10MHz reference has nothing to do with sweep or frequency

The way the 2465 family creates its sweep is by using a
miller integrator, and precision integration capacitors.

Very nice explanation of the principle used to make the measurements, now I have much better understanding of the process.

It is standard practice of most sellers to remove all
calibration stickers, and stickers showing previous
ownership before the sale. Although I don't sell a lot
of scopes, when I do, I blow out the dust from the inside,
clean the outside, and the CRT, make any repairs, and
calibrate the scope, complete with zeroing the counters.
If I may ask, how do those hour and power cycle counters get zeroed out? I don't think I have seen the reset procedure explained in the service manual.

According to Manuel Maseda, Option 46 is the military
version of the scope (OS-288/G) that includes option 10
(IEEE-488), and 2 probes.
Is there a more specific service manual for this variant I should look for?
If you happen to know, are there any differences in the military version from the regular version?
Perhaps a sturdier build? or what where the military requirements?

Thanks again Chuck.


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