TSP #134 - Teardown, Repair & Analysis of an Agilent N5230A 13.5GHz PNA-L Network Analyzer (Part 1)

In this two-part episode Shahriar repairs an Agilent N5230A 13.5GHz PNA-L which suffers from un-leveled output in full frequency sweep range. The instrument is not able to produce any outputs above -25dBm above 10.5GHz and shows below specification output power levels below 10.5GHz.

Teardown of the unit reveals various microwave modules with the SSLAM final module responsible for amplitude leveling and frequency multiplication for frequencies above 10.5GHz. Teardown of this module shows a collection of MMIC dies wirebonded together using micro-strip ceramic pieces and interconnects. MMIC include switches, amplifiers, filters, multipliers, power detectors and attenuators. After examining the input/output signals of the module it becomes clear that the input switch IC is damaged. Unfortunately, an attempt to replace the die with a packaged QFN GaAs device fails. However, a lucky eBay find of a used SSLAM module saves the day and the instrument is restored to full functionality. Some measurements of an packaged evaluation board of a GaAs IC is demonstrated using the newly repaired PNA-L.

The Signal Path

[Thesignalpath]

*Don't forget to watch to the end and let me know your thoughts on how to proceed.*

[darrellharmon]

The 5th channel on the Quintbrick mixer and IF digitizer is for use in the 4 port PNA-L. As a low cost 4 port, one incident channel is shared for all 4 ports with the splitter before the port switch. It makes TRL family calibrations impossible without another method to determine switch terms. PNA-X and probably the regular PNA have 8 receivers on the 4 port models.

[BarriosGroupie]

Such a privilege to witness the genius of electronic engineers in 2018

[scottvance]

I had the power supply fail on our N5230A. The replacement was quoted at 2K, but instead I just took it apart and replaced the two bootstrap capacitors, fixing it for about $2. Thanks for your very helpful videos.

[pesat]

People seem to forget that the journey might be nicer than the "destination" - What a great video. Thank you very much.

[JlerchTampa]

Reminds me of the point to point wiring seen in the Vacuum Tube era, just a bit smaller and all gold plated. Great content and details, looking forward to the next video!

[maor]

Hey Shahir, great video.

I suggest you attempt to buy the die and perhaps go to one of the unis near you and see if they have a wire bond machine? might make a good video as well.

[waverleyrocker]

Epic video. Jamming in a QFN switch would be mighty impressive but i would be equally interested in wire bonding. I eagerly await the conclusion.

[hpux]

Just awesome. I'm definitely ill-equipped to tell you how to proceed, but I appreciate that you split the video and taught us so much!

[MC]

Mikeselectricstuff's talking speed is contagious.

[tariqmehmood]

I am dying for the second part and want to see how you Replace/fix those microscopic compnents..

[yaghiyahbrenner]

Beautiful man, even if this doesn't work, I really learned so much watching this video. first time vie ever seen someone go this deep on an RF repair! using a small QFN swicth will be interesting!

[PapasDino]

There are those darn probe power connectors we were never able to find a couple of years ago!

[robertwatsonbath]

Nice video Shahriar, thanks. Interesting - never seen that kind of mesh bond before. Know of any test equipment breakers that have any used complete modules? There area few on ePay that come up. On the other hand I'd like to see a 'hobbyist'-style best-efforts fix with a packaged SPDT switch.. but that's a bit of a one-way mission.

[dxdrive]

There is a 7 second offset of the audio from the video during the block diagram portion. At least on my computer.

[Factory]

Wishing I had a few spare wire bonding machines....I would send one over right away.

[SaabFAN]

I'm a bit conflicted - On the one hand, I would like to see a repair with a QFN-Chip to see how well a packaged chip that is 21 years younger can hold up against a bare die. And also to see if such a device can be repaired in this way (if so, ebay-prices for defective network-analyzers will spike again, I think :D).
But on the other hand, I would also like to see how a wirebonding-machine works and how the dies and ceramic modules are being put into the metal casing. As well as how to remove the die without having debris flying all over the place, possibly causing further damage.

Either way, it'll be a very interesting 2nd part. :)

[gwyllymsuter]

Excellent analysis as usual. Wire bonding machine on alibaba for a bit less than $2000 would be the trick. No point buying it unless you're absolutely positive a die is available for purchase.

[procactus]

Your videos are so damn clear !
And one has to marvel of the beautie of the engineering of the whole thing. Then you say 'jam it in there', I nearly got hernia :D

[topherteardowns]

A special saturday night treat! A repair video. Most excellent!

Followed the block diagram along with you, I liked this way- laggy pc or not, still learned a great deal

Test the mesh for open (moderately) separated-waveguide RF transmission attenuation too! (Along with the other suggestions last videos!)

40:41, the damage, hypothesis to what caused that? Was that more of an "etch" damage or "crusty" damage? Probably irrelevant, but, curious none the less

As far as proceeding on part 2, it sounds like your plan of attack is the best choice (considering the equipment, or lack there of, at the moment -it would be VERY cool if you got a wire bond-er though!)
..bout the only other thing that may be best, is just finding a new module -maybe the none "L" versions would have a comparable one that could be found as "parts/scrap" and used just as well

Anyways, great video!
As usual
Learned a lot and loved the look into the high tech side of electronics. Absolutely beautiful.
*Thank you, again and again