#44 - HP 8590A spectrum analyzer repair - part 2 of 3

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In the previous video I replaced a par of blown diodes in the RF mixer of HP 8590A with Avago (Broadcom) HSMS-2802. In this video I experimented with HSMS-2812, HSMS-2822 and even with unmatched pair of 1N5711.
Previous video: • #43 - HP 8590A spectru...
Forum: www.eevblog.com/forum/repair/h...

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9 май 2016

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Комментарии : 13

@andymouse 4 года назад

Fascinating, those RF filters just look like "alien" tech...cheers

@firstnamehidden6514 4 года назад

Thank you for doing this series. I recently purchased an HP-8590A that has the 2.9 gHz option. It passes self cal and test. RF amplitude readings are basically bang on but ultimate sensitivity of -130'ish dBm is not obtained in narrow bandwidth measurements. I can only measure to -90 dBm but I am not impaired by this little detail. The built in 10 dB input attenuator is always in. I have not learned how to defeat it like I can on my much older HP 21 gHz analyzer in the 141T storage mainframe from the 1960's. It was very helpful to learn how to feplace the mixer diodes if I need to. Thanx! I noticed a difference between your front panel and mine. Left lower knob is labelled Intensity. On mine that same control is a Audio output volume control to listen to the signal demodulated. I have not gotten that feature to work although there is a noise in the speaker during boot up that indicates a speaker present and hooked up. Anyone know anything about this audio feature?

@longeron Год назад

Zero dBm attenuation can only be selected via the keypad. This is to prevent inadvertent overdrive of the input section (possible risk of damage for high power signals). Try SPAN, ATTEN (first softkey), 0 (keypad), ENTER (bottom right of keypad).

@amikhimji 8 лет назад

Great video thanks

@OctavMandru 8 месяцев назад

I wonder how germanium diodes would fare. Given your results and the oldness of the equipment, it would seem possible. Even the matching might be possible with some regular octopus

@The411 4 года назад

I need these toys! No idea what for but need them...

@PapasDino 8 лет назад

Also add my thanks for making the follow up effort! Is the rectangular space around the "span" value displayed on the CRT where the graticule dots disappear intentional? I'm not familiar enough with the HP series of SA's. Keep the great videos coming, always learn something new!

@feedback-loop 8 лет назад

+Dino Papas I think that the blank space is intentional.

@thomasguilder9288 8 лет назад

+FeedbackLoop yes it is :)

@Ogma3bandcamp 8 лет назад

Thanks for the follow up. Shame you didn't see a real improvement for persevering.

@evilsdevils 8 лет назад

+InnaSoulSounds Dude! Spoilers!

@Ogma3bandcamp 8 лет назад

So as I was saying... Game of Thrones, guess who snuffs it this week.. lalala.. :)

@feedback-loop 8 лет назад

+InnaSoulSounds > Shame you didn't see a real improvement for persevering. I think the unit needs some adjustments. Too bad that the service manual is not clear. I tried following initial steps of some of the procedures, but they were so vague, that I didn't risk it yet. And there are many corrections in handwriting all over this manual, which I downloaded from Keysight. And there is no explanation of how to measure the coefficients of flatness, which must be entered manually. Perhaps, I don't have a proper equipment, but it would be nice to know.