EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: Hugoneus on October 10, 2014, 08:27:52 pm
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In this episode Shahriar takes a close look at an HP/Agilent 5347A 20GHz Frequency Counter and Power Meter. This defective unit does not provide any frequency information from Input 2 which is rated to operate up to 20GHz. Before the teardown and repair attempts, the principle operation of the instrument is reviewed.
The properties of a Step Recovery Diode (SRD) is presented along with the theory and practical aspects of generating a frequency comb. The heterodyne architecture of the frequency counter is explained in detail with the mechanism of detection and calculation of the input frequency.
During the teardown of the unit the synthesizer board, motherboard, power meter reference board and the main RF assembly are shown. The schematic of the synthesizer board and the RF board are also described. The defective component is identified and examined under the microscope. The slides for this episode can be found at The Signal Path website.
You can watch the video here: [1 Hour]
https://www.youtube.com/watch?v=-RpwE_uxgjM (https://www.youtube.com/watch?v=-RpwE_uxgjM)
More videos at The Signal Path:
http://www.TheSignalPath.com (http://www.TheSignalPath.com)
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Good video!
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Good video.
I would like to know how he removed the cap off the detector can.
The 5347A detector seems similar to the detector on the HP 5350's - some kind of gray adhesive holding the cap to the base.
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Great video again and very educational.
Thanks.
If indeed the Step Recovery Diode is broken in the special HP can, why not removing it and replacing it with something that would come close?
May be a long shot but possible?
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Just started watching.
Heh. Cats like sitting on high points, due to their learned/instinctive adaptation to flea behavior.
Fleas on cats sometimes jump off. Fleas not on cats attempt to jump towards heat sources. Cats can feel when a jumping flea lands on their fur - and they hate it. They notice that when high up, it doesn't happen. This is greatly preferred by cats. Also any flea eggs will fall off high spots.
It only takes a short episode of having fleas, for a cat to learn this. After which they strongly prefer high spots, even when there are no fleas.
In the start of your video, lots of waving your hand around near the fascias of nice instruments, while holding a screwdriver. Way to make your technical audience uncomfortable.
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Easy to replace, all you need is a new diode, some silver loaded epoxy and a spot welder and gold ribbon to get the replacement in there. All done under 200 times magnification under a Mantis, along with a class 100 clean room to do it in. You do not really need a better clean room, provided you clean it after repair and make sure there is no dust or debris before you put the can lid back on with more conductive epoxy.
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Easy to replace, all you need is a new diode, some silver loaded epoxy and a spot welder and gold ribbon to get the replacement in there. All done under 200 times magnification under a Mantis, along with a class 100 clean room to do it in. You do not really need a better clean room, provided you clean it after repair and make sure there is no dust or debris before you put the can lid back on with more conductive epoxy.
I think the diode itself is fine. It is the sampler that is bad. Either way, difficult to do a replacement, I'll look into it.
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The diode is the sampler, the rest is solid copper and such, unless a resistor or the FET switch has gone bad. Even that will be repairable with some fine work and appropriate parts with conductive epoxy to attach them.
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Here's how HP used the same technique to measure frequencies up to 15 GHz - oops, I should say 'gcs' since they didn't use Hertz back in 1964. Instead of using an SRD, they used a harmonic mixer. Everything is done manually. I actually bought a 2590A converter a couple of years ago and it still works! I used a synthesized input frequency of 987 654 321 Hz. After I finished the calculation (!), the measured frequency was 987 654 321 Hz. Not bad for a 49-year old piece of equipment!
http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1964-04.pdf (http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1964-04.pdf)
Ed
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Here's how HP used the same technique to measure frequencies up to 15 GHz - oops, I should say 'gcs' since they didn't use Hertz back in 1964. Instead of using an SRD, they used a harmonic mixer. Everything is done manually. I actually bought a 2590A converter a couple of years ago and it still works! I used a synthesized input frequency of 987 654 321 Hz. After I finished the calculation (!), the measured frequency was 987 654 321 Hz. Not bad for a 49-year old piece of equipment!
http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1964-04.pdf (http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1964-04.pdf)
Ed
Nice, thanks for sharing.
Everyone also has the same haircut. I would have never fit in! O0
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A few were asking for the slides, here they are.