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New for July 2016: Here's a contribution from Dave B:
Reported fault "Input socket missing." Well, we found it OK! Mostly. The part bolted to the inside of the case at least. The gold coloured strips, are the remains of the resin pin used to lock the centre conductor in place. Said centre conductor is totally missing.
OK, it's not difficult to break these, but you have to wonder...
New for June 2016: this came from Andy B:
Today I customized a part in a way that maybe MW101 readers would be interested in…We were testing a resonant LC match designed to match 50-Ohm line to a 13 kOhm load (and boost the voltage by 16x in the process). A home-made tunable capacitor had plates spaced apart by Nylon stand-offs, as seen in the photo. It seems the dielectric heating of about 2300 V r.m.s. at 13.56 MHz isn’t good for Nylon. In retrospect, some of the team “knew” that but in the heat of prototyping forgot. I hope the new ceramic standoffs work better!
New for May 2016: here's three videos from Lugansk, Ukraine. This is an independent country regarded by the Ukrainian government as an occupied territory. These gentlemen remind us that even in the face of overwhelming calamity, there are some great people there in Ukraine, and some of them are so interested in microwave technology that they find unconventional ways to explore it. You can send them some funds through PayPal, if you want to buy them some lab equipment or bullet-proof vests. Maybe the IEEE Ukraine section could recruit some new members here. However, it is probably not a good year to hold a conference in Lugansk...
"Boosting*" Wi-Fi signals
* Boosting has two meanings.... to increase, and as slang, to steal.
Now, let's take a tour of the city of Lugansk, right on the border with Russia, and count the un-exploded ordinance. You know how you were complaining about pot-holes in your own town? Please shut up about that and stop cheating on your taxes.
Greetings from Lugansk
Below is a video of a very dangerous practice. We don't recommend taking the magnetron out of a microwave oven and melting stuff with it.
Microwave Oven Weapon!
New for March 2016: What happens when you try to measure 1700 Vrms with a Fluke 87IV multimeter? Thanks to David. Note that the calibration sticker is still valid!
New for February 2016: Here's an RF connector that was found on a "flaky" piece of test equipment. That's all we can say!
New for November 2015: This image from CFH. This is what happens when are connecting the positive terminal of a large UPS and are not careful. Ouch! This is why you are supposed to disconnect the negative terminal first and reconnect it last...
New for September 2015: More images from Jacob, plus a bonus video of a vacuum tube frying!
Have you ever thrown away a memory stick that had data on it that you wanted but thought that it was lost?
Today a colleague of the IT department asked if I could repair a broken (as in two pieces) USB stick. The USB stick was installed in the front of a PC which was on the floor. Someone hit the USB stick by accident and the pcb traces came off the pcb. Note; the same colleague always strongly advises not to place computers on the floor to prevent this types of accident. ;-)
Well, the repair... I like soldering, but SMT isn't my favorite. I like challenges and this seems a good one to test my skills. After cleaning the connector and scraping off the protective paint of the copper traces, the two pieces are placed onto a breadboard pcb using solder wire and double sided tape. Then four small wires are used to create the point to point connection. The thickness of the wire is 0,25mm/0,01" (AWG30). The soldering wire is four times thicker and the tip of the soldering iron is even six times bigger than the copper wire. That's not the ideal equipment, but surprisingly the "repair" went quite well and rather fast.
Luckily there was a stereo microscope which made the job quite easy. And the assembly works! The documents are saved and this USB stick is added to the hall of fame (or shame...)
The other day I started a repair project of a recently bought Kenwood TS-830M ham radio transceiver. The previous owner said there was "some problem" with the transmit function. After a thorough visual inspection the radio was hooked up to a variac. The voltage was (without any trouble) raised to mains level and some receiver functions were tested. I had a hunch that something was wrong. Therefore I setup a camera to record the final amplifier stage. During testing I checked the tubes visually and there was nothing wrong to be seen. Until two minutes after the powering up of the radio. The left tube started red plating, which I didn't notice.
One minute later the left tube failed by a bad flashover. I haven't examined the tube yet, but it's very likely that there's a grid/cathode short inside the tube. Grid/cathode short circuit seems to appear sometimes in these 6146B vacuum tubes. This all happened in receive mode.
The bad thing is that the previous owner soldered a wire across the (blown) mains fuse. (...) You probably can imagine the resulting damage. Probably this isn't the first time a seller lied.
New for September 2015: here's a photo of a dead hotel room key, caused by dropping a microwave circulator on top of it. Say, what do circulator suppliers do with that suitcase of product when they travel to trade shows to prevent this and other catastrophes? Our guess is they remove the magnets from the samples in the sample case.
Click here to learn if a cell phone can erase a hotel key.
New for August 2015: Here's some images from Cedric.
The pictures I attached are my most spectacular device failure to date. I was biasing a 1-port interdigital ferroelectric varactor at 80V when it decided to give up quite dramatically. Unfortunately, when the device blew, it took the $1700 Cascade Infinity probe with it. Sorry for the poor quality. I snapped them with my iPhone through the eyepiece of our probe station microscope. Hope you enjoy the pictures!
New for August 2015: here's a second installment from Jacob. I too have experience similar problems with the Ebay and Amazon "shipping departments"... what are these people thinking? We shiipped Jacob a M101 coffee mug and we are happy to report it arrived in one piece...- UE
Today I received two waveguide attenuators which I bought earlier this week. (For the record; model J382A and P382A, both from HP.) The "small" is in good shape, the "big" one... not so good. Since it was not packaged well enough, during transport one flange is badly damaged. The compression mark on the box can clearly be seen on the image, along with the other half of the flange. Luckily the cartboard box is not damaged badly and therefore it can be used again. ;-) And the attenuator... well, probably the housing will be used for another ham-radio building project...
New for July 2015, from Jacob from the Netherlands. He asked that we fix his English, we decided (we were, like...) it is as good as most American college students so corrections are not (like) needed. Like that, likers! Jacob, we are boxing up all the non-working equipment in our garage and sending it to you....
Anyone who repairs old equipment are probably familiar with bad capacitors (by aging). Mains noise from old tube amplifiers is one of the indications of bad capacitors. Sometimes bad caps can be found by visual inspection since they start to bulge. This week I found two caps in a (still working) device. That they went bad could be seen from one meter distance... The first one is leaking (a lot) of fluid and is very bad corroded. The other one is dried out. When it was shaken, there is clearly a rattling sound to be heard. The exact age of the caps isn't known. They are at least two decades permanent in use; at least 175.000 hours...
On the image in the middle are two voltage regulators shown. The right one is as it should look like. The left one is exploded. It's very likely this happened by overvoltage and not by a production fault.
On the image is a Siemens Logo! plc shown. This (brand new) one was wired to 230VAC. Since this is a 24VDC model, the result was a lot of smoke and a 16A blown fuse. Since my colleagues know ham-radio operators can use all kinds of broken equipment for components it was brought to me. Fixing was worth trying so the relics of the evaporated component were removed and the evaporated pcb trace was replaced by a piece of wire. After cleaning up the black stains, the plc was wired to a 24VDC power supply. And it's alive again! Resurrection after electrocution is not bad I guess..
New for June 2015! Most Big Companies have a Company Store where you can get your kids outfits with the company name on them for the summer picnic in order to kiss up to management. Click here to listen to Tennessee Ernie Ford sing about the company store. written when the this institution had a darker connotation... All manner of items can be purchased at the company store, even golf balls. It came to our attention that Northrop Grumman ordered a large quantity of golf balls with their name inscribed. Too bad whoever place the order with the Chinese supplier didn't know how to spell "Grumman" . We've all seen "Northrop" spelled "Northrup", but come on... Thanks to The Other American Pharoah!
New for May 2015: This image came from Bill in Tampa. An unlucky squirrel crawled into a power meter and learned Ohm's Law the hard way. Ouch!
New for May 2015: This image came from Bill in Tampa. An unlucky squirrel crawled into a power meter and learned Ohm's Law the hard way. Ouch!
New for March 2015: this image is a photo of a booth at GomacTech 2015. Check out the way the dime has been sliced by the camera. Or was it circumsized?
New for December 2014: This image came from Steve M.
An LG en V3 that had a run in with a John Deer mulching mower...
New for November 2014! This image comes from the Unknown Editor himself, who has been busy ripping out some 1990's era wiring obviously done by an amateur. Below is an image of a 110 volt ground loop... a buried junction box (does not meet code) connects two 20 amp branches (they are cut off about four inches out of the box) to a single three-conductor wire heading back to the 200 amp panel. These two branches (red and black) now share a neutral wire (white), so 40 amps could return through a single 12 gauge wire (does not meet code). If this mess burned down your house, good luck getting a check from your insurance company. Check out our new page on ground loops to see how miss-wiring like this affects microwave products and measurements every day!
Update: as John pointed out, if the red and black wires are across opposite sides of the 240 volt rail, the current in the neutral will tend to cancel and not add up. This might be the case if a double 20 amp breaker was used. However, in this installation the red and black wires were connected to separate breakers that were mixed up in the 200 amp service panel. Maybe once upon a time they were connected properly, but eventually after an upgrade or two they became connected to separate breakers. Why take a chance with wiring just to save one conductor?
New for July 2014! Here's a video of some people destroying $30,000 worth of equipment. They must like breathing toxic waste, as they did it indoors. No smoke detector in that lab obviously. They have lost the deposit on that property rental, as someone will have to wash and paint the ceiling. A great example of an overall stupid place to work. Thanks to Bruce, who suggests:
If you know anyone who is into 900 MHz amateur radio, this one will make 'em cringe...
New for February 2014! This came from Darrell, the microwave version of taped nerd glasses. Darrell also helped us out with some new information on mitered bends in microstrip (thanks!) Click image for more detail....
.... a photo of some glasses I repaired with some semi-rigid coax in college.
New for December 2013: thanks to Walter, we have the following "good example" of an antenna installation, directly from Brazil!
New for October 2013: This image came from Robert, an academic type that likes to build things too. Thanks!
I was wandering though the lab of a colleague and came across this (attached). I could scarcely believe what I was looking at - a length of RG58 coax soldered onto an N-type male-to-male coupler to form a makeshift N-type "plug".
Thankfully I make sure our technician keeps all of my good microwave cables and VNA cal kits locked away!
New for September 2013: this TO-3 disaster came from Andy:
I was using an LM338 voltage regulator in a 24V PSU to power a 100 Watt DC motor. I inadvertently swapped the leads over while it was running at full pelt. It immediately turned into a generator and forced a huge backward current into the regulator, resulting in total destruction of the device.
The TO3 can was easy to cut open to view the carnage under a microscope
New for June 2013: This came in from Matthew:
Here I've got a GSG probe which has seen better days. An RF FET was being tested, and I think that it had some contamination under the source airbridge which caused a drain to source short. The FET evaporated with an audible snap. Fearing the worst I looked into the microscope and saw this. I think that the probe was hit with some of the shrapnel from the FET which bridged the contacts causing the melty result here before source compliance could kick in.
New for April 2013: These photos came from Dave:
Here is an interesting item. From a High Power HV SMPS, that is part of an old Varian TWTA. One of the noisy types that scream at some 4 kHz.... 200W out CW, 2 to 4 GHz, one of the "old school" types.
SnubberFail-1, the overall view of the board after we removed it from the amp. Even more spectacular when you realise that the amp was still usable in that state! We were told that it "just made a pop" but carried on working. The customer only took the lid off to look, after finishing some testing.
That board is the main Switching Regulator card that in turn feeds the inverter that (literally) whistles up the HV. It's fed from raw rectified 230VAC. (No such thing as PFC when that was built!)
What's not shown, is the mass of resistor wire that spilled out of the exploded resistor, that in turn was entangled around all sorts of stuff, while still connected to the raw DC etc. I guess it's insulated, as there were no shorts or other explosions. No fuses were harmed either!
I apologise for not reacting in time and getting a picture of that mess, but even so, it's remarkable this unit survived relatively unscathed, and carried on working after the "Pop" (they say...)
SnubberFail-R and -C are closeups (as much as a phone-camera will allow) showing the result in detail.
The cap is (was) a 10,000pF 500V Silvered Mica part. What caused it to fail we don't know, that and with all the other high power RF and switching stuff we deal with, we've never seen a Mica cap fail like that before. Or for that matter, one of the aluminium clad resistors explode...
After stripping many parts from the board, giving it a good scrape wash and brush up, refitting the removed (good) parts back in their original positions, plus a new resistor and Silvered Mica cap, normal service was restored (we went through the recommission after repair procedure, but found no issues) resulting in a happy customer to boot, who were bracing themselves for a rather large replacement amplifier bill. Not that with the time involved for all the above, it was a low cost fix, but much lower than the replacement cost of the entire unit.
After that, they then brought us (the day they collected the Varian) an old Logimetrics Pulse RF TWTA, that wouldn't do more than about 2% duty. (It was spec'd to at least 40%) We found a failed resistor in a medium power stage that caused the Grid drive to fail when pulsed beyond a low%, tripping the HV as a result. Another old but high value bit of kit saved from the skip. What they will bring us next, who knows...
(Click on images to view close up)
New for February 2013: This photo or the spectacular 2011 television tower fire and collapse in Hoogersmilde came from Ivo:
Today I had a look at your Microwave Mortuary pages….fantastic!!
It remind me of what happened here in The Netherlands at July 15th, 2011. A local 300 meter TV-tower collapsed due to a fire in the tower.
You can find more info (sorry; in Dutch) on:
This is a good chance for you to try out Google's translator, check it out! be sure to click the links at the bottom of the page to see a zillion high-res images of the carnage, plus videos.
Also, this is a appropriate time for us to review the story of Hans Brinker, although it is more of piece of American culture rather than Dutch, they did create an awesome and inspirational statue of the boy and the hole in the dike to remind us all of what we do every day at work- UE
New for February 2013: these photos came from Tom, we'll let him tell the story. But let's first point out first that Teddy bears in museums deserve more respect, especially Misiu. And the movie Ted should win Best Picture for 2012 in our opinion.
Here at our facility, visited by thousands of happy children and their families every week, we have a pool with four Tornado remote controlled boats (not the Tornado corporation that makes rigid inflatable boats for people to ride in, but the one that makes amusement park interactives!) Anyway, over the past nine years of operation, at times the Tornado boats like to prove the old adage that electricity and water do not mix.
Over time the 12 volt DC power to the motors (which are beautiful Swiss made Maxon DC brush type and survive insane high mileage) simply made the traces Go Away.
Also, you will find attached the control board from a "ClearVue" condensate pump, on which the pump's holding tank apparently overflows right into the control board the first time it has trouble keeping itself drained, a karaoke booth that got a morocca through its monitor, and what some of our guests did to a giant teddy bear.
The one of the broken ELO Touchsystems monitor is curious and haunts me to this day. I still stay up at night sometimes wondering what possessed this one fifth grader on a class trip to decide to interact with the karaoke booth menus by smashing the Surface Acoustic Wave touch sensing glass with a morocca. I even nicely asked the child after the fact but he was inconsolably crying and could not get a word out. It will be a mystery forever.
Here are links to our archived Mortuary pages:
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