The eBay addiction starts small. One night you’re buying $3 buck-boost converters and cheap Chinese USB power packs. The next thing you know you’re spending thousands on dead instruments with no documentation. You’ve got the skills though, and if your bet that you can diagnose and repair a 14 GHz real-time spectrum analyzer is right, you’ll be putting a snazzy instrument on the bench for a fraction of the original $50,000 it cost.
Make some popcorn and get cozy before settling in to watch [Shahriar]’s video below, because it clocks in at just over an hour. But it’s pretty entertaining, and just seeing how Tektronix built the RSA 6114A spectrum analyzer is worth the time. Things are different when you’re piping microwave signals around the chassis of a beast such a this, the interior of which is densely packed with pluggable modules. Tek factory service would no doubt perform a simple module swap to get this machine running again, but [Shahriar] wasn’t having any of that on his $2,700 eBay find. After isolating the problem to the local-oscillator generator module, [Shahriar] takes us on a tour of where the signals go and what they do. We won’t reveal the eventual culprit, but suffice it to say that after a little SMD rework, [Shahriar] has a very fancy new instrument for the shop.
If this repair gives you the itch to get working on microwave circuits, maybe it’s time to build that backyard synthetic aperture radar set you’ve always wanted.
Thanks for posting this one. An hour really well spent; he really knows how to explain and talk through things. Fascinating.
The video almost makes me want to cry. He’s got like a quarter million dollar’s worth of test equipment on his bench… It’s not just that he’s insanely better equipped than my home lab — he’s insanely better equipped than the lab we have at work!
I think you might be low balling it here, I think it’s more than 250k$ …
Imperial dollars vs Metric dollars?
It’s like saying the time as ‘a quarter to twelve’ just to feel the room get a bit warmer from all the extra neuron/synaptic activity.
Is ‘quarter to’ not a common way to say a time in your parts? Here in England it’s pretty usual.
Here in Australia, too
When someone once told me “it’s a quarter OF three”, I wondered which quarter? There are 4 quarters in an hour, and they didn’t specify which one.
@Ren: Maybe they meant 12:45 (3/4*60 = 45)
Common in the US too, at least with people old enough to be comfortable with analog clocks.
Alternative dollars.
Actually, the unit had a base price of about $80,000 and the 110 MHz capture bandwidth card alone at list is about $12,300. So with some other options thrown in, (Shahriar did say it was pretty loaded) I’d say the unit msrp is about $140k. The $50k price is about what it’s worth on the used market today. Really nice job on the troubleshooting and the fix.
for that $2700 couldnt you reformat the hard drive and install windows on it and use it as a 14ghz pc?
Haha. Well it is already running windows! :)
are you really that stupid? how did you even found this site?
come on be nice…it would totally worth it using windows 98SE or millenium
Yeah ! a $2700 gold plated turd !
if you noticed it booted windows xp so it makes sense that it could be made into a pc or even hackintosh
If you’re going to be that big of a jerk, could you please stop coming to this site?
learn how to word. its ‘find’, not ‘found’.
I think he’s accusing him of founding Hackaday
Your second sentence confirms you are the stupid one.
You might be a way off windows but with a few dozen of these and some delay line memory, using resonance for logic, you might get a calculator.
+1
Hardware acceleration, some bit of it’s handling the 14GHz stuff but it’s sure as heck not the CPU, that’s only 1.3GHz with 2GB of RAM :P A netbook on ebay would be a better purchase for PC use.
That’s silly. But I thought it would be a nice idea to make a backup of the original hard disk and/or put an ssd version inside, just for the sake of speed and security.
I was thinking the same thing with an SSD. I’d probably take an image of the drive and try to toss it on an SD card that I could tape in there too. Pretty common to run into <100gb disks in instruments like that from that era.
Hard drives / SSD’s shut down cleanly with a power off. SDs cards can become corrupted.
Pretty sure simcop is talking of using the SD card as an offline backup.
I like the sheer number of people without a sense of humour calling you the stupid one and saying you don’t belong here.
Well trolled sir. :-)
14ghz is not the speed of the pc. Its the highest radio frequency the device can sense. that sensing is done by another circuit and the PC i just there for the GUI.
Bahaha nice one. :D
Support Shahriar’s “The Signal Path” (TSP) Site – I can’t emphasize this enough! There are too-few EE Blogs dealing with RF analysis & teardown. Don’t get me wrong, I love the likes of Dave’s EEV Blog site, but it is a virtual DESERT when it comes to serious RF stuff. EEV Blog and The Signal Path compliment each other, so support BOTH. But again I think Shahriar’s site deserves more support than it is getting. Yes the posts on the TSP site are less frequent than the EEV Blog, but look at the content and depth you get on the TSP site in comparison.
Thank you.
Totally agree. I have watched every single video he has posted. I really appreciate people who have so much knowledge in their field and are happy to pass it on, more people like that and we might just fix the world. Education is the key. Thanks.
Dave is a snowman. He does entertaining shows, but I rarely find anything really interesting in them. Shahriar does a great job not only taking on RF magic, but also explaining in detail what he’s doing and how things work. I already signed up to support him, and until he will not try to build a walled ghetto videos and posts accessible only for his supporters, I will happily put my money in the basket to help him bring more topics that nobody else has knowledge and courage to talk about.
> Dave is a snowman.
Lol! s/snowman/showman/
No. He had it right. Our favorite semi-hysterical Aussie performs great ‘snow jobs’ which give the impression he knows what he is talking about.
Sadly, the reality is somewhat different…
Even worse, as I and others have pointed out many times, there are very few alternatives.
I have no intention of making my videos exclusive to my Patreon supporters. The whole idea is free and accessible knowledge for everyone. Support is voluntarily and appreciated.
I’m very glad to see it. Please keep your videos open to everybody, and I will support you on Patreon.
+1.4^10
Thank you for your contributions to knowledge.
I think Dave’s pretty good. He’s clearly very knowledgeable though he’s often said in depth RF design isn’t his cup of tea (and in fairness it’s very few people’s cup of tea :) And the people that are into it would often be under heavy NDAs for the things they’re working on.
But I like the way Dave makes electronics accessible. I’ve even heard some of my non-ultrageek friends taking about him.
But I’ll definitely check Shahriar’s blog out now!
Dave is very knowledgeable, but the videos he makes are addressed to less advanced part of the audience. That’s really great that he educates his viewers and helps start with the hobby; However, for more advanced hobbyists there is much less value in them.
I think there’s a good reason there’s almost no content out there. It’s a REALLY expensive field to get into. Just a very basic chinese spectrum analyzer will set you back like $1500, and a basic VNA on the used market is about twice that… Add to that a bunch of other stuff (probes of all kinds, antennas, cables, attenuators and stuff) and you’re well outside the means of 99% of hobbyists. A Fluke 87 and Rigol DS100Z is already stretching most hobbyist’s budgets. It’s quite interesting but I’ll never have that much money to spare, even if I’ve started making some boards with RF stuff (using CC3100/CC2650 ICs)
Check out the RF Explorer. Sure compared to lab stuff it’s a toy but it’s cheap for what it is and portable so it suits HAMs well.
I completely agree with Drone. Shahrirar’s channel is one of the best RF / electronics resources on youtube. In fact, it is the best I’ve run across. I was going to support when I saw his call for it, but I couldn’t figure out how to without a Facebook account. Please add a paypal option or something like that Shariar. I will donate. You are the man.
Create account on Patreon. You don’t need to use Facebook account.
Thanks. I forgot it was patreon and not Facebook. Still, I have no idea what that is and don’t really want to enter credit card # there. Would prefer donating with Paypal.
You can use Paypal with Patreon.
I prefer “Mr Carlson’s lab” style.
The only one I support with my meager revenues.
At last a video that makes it worthwhile having you tube, all previous sins are forgiven.
All previous sins, are you sure? The most outrageous conspiracy theories, cat videos, fake news, the signal to noise on you tube is pretty bad.
its in correlation with the number of useless humans.
Now I know you’re trolling… Calling cat videos a sin! For shame!
I don’t watch fake news on Youtube either though… If CNN pops up, I close the window FAST! :P
I thought it would be a nice idea to make a backup of the original hard disk, or put an ssd version inside, just for the sake of speed and security.
+1 for the HDD backup.
Last thing you’d want to happen now is have a HDD failure!
I find it ironic that you mention an HDD failure and your name is 0xFFFF, lol…
Yah I’d definitely make a backup image of the hard drive in his case.
+1 for backup! Also check if the device only accepts HDD with a specific size or from a specific manufacturer or even with a specific ID or don’t no what. Seems like they are devices like that where you need to buy a genuine replacement (for $$$) from the original manufacturer (if he still sells these parts…) instead of a generic part (for $ only).
This is a very interesting video by someone who is obviously extremely knowledgeable, but I don’t understand his ESD protection methodology. Grounding himself and leaving the equipment electrically floating while sitting on a towel doesn’t ensure he and the equipment are eqipotential.
Perhaps his technique is better than nothing because I would guess a person is more likely acquire a large charge relative to earth than the equipment is, but shouldn’t there be a conductive path (through a high resistance for protection against shock, of course) between the person and the equipment for real protection?
It’s likely that the equipment is electrically connected to mains ground, as is his bracelet.
Gambled on a $20 4ch 200Mhz ‘dead’ Fluke Scopemeter a few years back, just had a dead battery and wouldn’t power on without a good one. Best $20 spent!
OMG, having wireless grounding and a cat on the table while poking around with PCBs from a $50,000 device. that guy got balls of steel.
Well, thank you. The balls of steel are also grounded for ESD. :)
Awesome!
I once scored a Mortal Kombat (the first one) JAMMA board on eBay for $10.75, listed as “broken”. the board would reset constantly when tested. I just solved this problem with the Mortal Kombat JAMMA board (prototype version) I already had, and gambled on the issue being the same with the broken one on eBay.
the board worked just fine for me. turns out the problem (for both boards) was the +5 voltage out of the power supply was set too high. quick adjustment with a small screw driver and a multimeter and everything was good to go.
Have similar issue with a “sneaky” jukebox. If you take out the CMOS battery even if flat it wipes everything, causing Windows not to boot.
Never seen this before, even resetting to default does not work.
Little hint: sometimes they do this on purpose and use a dummy battery with no contents to force a reset on every boot, because the default is to power on with a flat battery when mains is connected.
+1 to copy the HDD, I use Winhex ™ well worth the $79.
Be nice and pay for the upgrades, Mr Stefan will appreciate it and he needs the money right now.
Did this sort of stuff everyday when I worked as a bench tech. Probably repaired several dozen spectrum analyzers. Don’t recall any of them defeating me. I’d have taken the chance without worry.
(I will admit however that I had real test equipment behind me when I repaired all those units. My home bench is far more modest, though I do have an 18GHz counter, rudimentary RF network analyzer, and RF power meter. This repair looked a bit beyond my availzble equipment.)
@Shahriar will you keep it, or resell it, and make a profit ??? :) to do more adventures on Ebay …
Sometimes the gamble works out, sometimes not (which is why it’s a gamble). In the past I’ve found some gems on ebay, but not always. I once forked out over $100 on a Fluke 1061 synthesizer… had only scrambled display on power up….only to find it had been gutted of just about every board except power supply and front panel. (I still broke even on the deal because they missed the 127db output attenuator. ) Had it not been for that one useful component I would have had just an empty box.
Another amazing video, I think it’s great the way you explain ur thought process! Keep em coming ! Oh, how much do u want for the wireless ESD strap? mine has become intermittent !
this is pretty cool
We have an article like this for a coffee can SAR at http://syntheticapertureradar.com/
Wow, I am relating to the article immensely. Then to see the latest comment before my comment…. I so want a SAR. Some day. Speechless. Man, I have a Tektronix 1740 that I picked up for parts, I haven’t tested yet since still working on the TDS-520 CRT and they are no way the RSA 6114A. I’m not up to thousands to invest yet. I may be about to invest in the HackRF however, so I have a cost effective frequency generator that sweeps. Any other suggestions or references for a signal generator with that bandwidth? Seems under 25Mhz is easier to make for the price.
I meant frequency range instead of bandwidth above. I bought the TDS-520 so I can have the bandwidth… man… must of been the stupid comments rubbing off.