Repair of $150k Phantom Flex 4k camera - advanced soldering - Page 1
Forum section: electronics / repair

author: rx8pilot
author_rank: Super Contributor
timestamp: September 08, 2019, 08:18:02 pm
content: My side hustle is diagnosing and repairing high-end cinema cameras. The Phantom Flex 4k is a high-speed 4k camera that is the standard for super-slow-motion shots in movies and television.Most of the issues on this camera are power-related and I have learned to diagnose and repair most of the component-level failures. This particular unit sitting in front of me has a number of cracked solder joints on one of the high-density PCB-PCB connectors. The straight connectors were a straightforward hand soldering fix under a microscope. The right-angle connectors are a different story. They are on a very high layer count PCB backplane with quite a few connectors on both sides. There is an inside row of pins that are well outside the range of any soldering iron. I have a good quality convection batch oven, but even that is a risk of damaging the other connectors or allowing them to shift out of position.Really not sure how to safely attack this one. I have been considering adding vapor phase soldering but that does not necessarily offer a magic fix. Under a microscope, I can see 5+ of the blind pins separated from the pads when looking through the tiny gap between PCB and the bottom of the connector.Anyone care to chime in with suggestions on this one?

author: dr.diesel
author_rank: Super Contributor
timestamp: September 08, 2019, 08:37:22 pm
content: Is it possible to wire around the backplane on those pins, bodge wire fix?

author: james_s
author_rank: Super Contributor
timestamp: September 08, 2019, 08:54:22 pm
content: Can you get in there with a hot air pencil? With the board preheated that might do the trick.

author: rx8pilot
author_rank: Super Contributor
timestamp: September 08, 2019, 09:24:54 pm
content: Quote from: dr.diesel on September 08, 2019, 08:37:22 pmI don't see an option for wires but the good news is that the pins on the edge appear to be primary incoming power and they are all parallel routed on the PCB. Shorts/bridges are not an issue in this area.Quote from: james_s on September 08, 2019, 08:54:22 pmI do not have a hot air pencil, just one of the larger hot air machines. This sounds like an interesting idea, however. I could do a basic pre-heat in the big convection oven, take it out on use the larger hot air system to keep it pre-heated from below while attacking the actual area of interest with the hot air pencil. It could work.Another element I am considering is machining some connector guards out of teflon to reduce the risk of damaging the good connectors. That may allow me to pump more heat into the PCB with less risk of melting the adjacent connectors. Hmmmmmm......An interesting point is that this PCB is not available for replacement if it is damaged. Nuts.

author: AngusBeef
author_rank: Regular Contributor
timestamp: September 08, 2019, 09:36:43 pm
content: https://www.allaboutcircuits.com/projects/tools-techniques-hot-air-soldering-surface-mount-components/Sent from my SM-T820 using Tapatalk

author: ddavidebor
author_rank: Super Contributor
timestamp: September 09, 2019, 12:08:32 am
content: What is the problem? the highlighted pins seem perfectly fixable by hand

author: Psi
author_rank: Super Contributor
timestamp: September 09, 2019, 12:11:49 am
content: Yeah, any pin/pad is fixable with a soldering iron under the microscope if you have the right tip.

author: Mr. Scram
author_rank: Super Contributor
timestamp: September 09, 2019, 12:20:25 am
content: You buy a $150K camera and they won't sell you parts? Or is the thing EOL?

author: rx8pilot
author_rank: Super Contributor
timestamp: September 09, 2019, 12:27:22 am
content: Quote from: ddavidebor on September 09, 2019, 12:08:32 amThe exposed pins are no problem with a soldering iron, it is the hidden second row of pins underneath the connector.Take a look at the image attatched. The hidden row of contacts is what is throwing the big party.SAMTEC:https://www.samtec.com/products/lsem-140-01-f-dh-a-n-tr

author: rx8pilot
author_rank: Super Contributor
timestamp: September 09, 2019, 12:30:50 am
content: Quote from: Mr. Scram on September 09, 2019, 12:20:25 amNo, they will not sell the parts to an end-user. They will only offer direct service where they replace sub-assemblies at eye-watering prices in addition to taking a very long time. That is largely why this has become a common camera to land on my bench. Most of the issues/failures are about $30 for parts and 10-20 hours of labor. It is a fun side hustle to do nights and weekends.

author: Psi
author_rank: Super Contributor
timestamp: September 09, 2019, 12:31:53 am
content: I find it hard to believe the inner row of connections will be damaged given that it is anchored from each side.One side from the TH mounting pins and the other side with the outer row of pins.But if one of them is cracked, then yeah, you could try carefully reflowing the entire pcb.If that doesn't work and you're sure that's where the issue is you'll need to remove and resolder the connector. (preferably a new connector)That's totally doable but very easy to stuff something up while doing it.Getting connector off with reflow oven and hot air shouldn't be too bad.Cleaning the pads is easy.But getting an even coat of solder paste back on each pad correctly will be tricky.

author: rx8pilot
author_rank: Super Contributor
timestamp: September 09, 2019, 12:38:23 am
content: Quote from: Psi on September 09, 2019, 12:31:53 amI can see the inner row pins freely moving when I look through the tiny opening between the PCB and the connector body. Sadly.....the anchors are not soldered at all putting all the stresses on the signal pins. Kind of ridiculous since this connector is subjected to a lot of pressures from the mating part.Quote from: Psi on September 09, 2019, 12:31:53 amI think I will make a stencil for this assuming I can get to that point.

author: ddavidebor
author_rank: Super Contributor
timestamp: September 09, 2019, 12:40:56 am
content: Quote from: rx8pilot on September 09, 2019, 12:27:22 amI would guess your best line of action is dumping a litre of no-clean flux on that thing and have it reflow in a professional reflow oven in some assembly house.With all of their work being eaten by Shenzhen fabs they're never picky.

author: Psi
author_rank: Super Contributor
timestamp: September 09, 2019, 12:41:24 am
content: ah, i see.My guess is that there was very little solder holding them on to begin with..

author: ddavidebor
author_rank: Super Contributor
timestamp: September 09, 2019, 12:43:12 am
content: But even then tough cracked joints may not reflow properly if the surface tension toward the pin aided by the oxidation makes them not touch...

author: ddavidebor
author_rank: Super Contributor
timestamp: September 09, 2019, 12:44:59 am
content: So maybe it's better to remove them and reflow a new one IF you can remove it safely, which is quite hard. With than many layers you need heathing on both sides to avoid damage.

author: Psi
author_rank: Super Contributor
timestamp: September 09, 2019, 12:48:24 am
content: Yeah, i think the only way to fix it properly is to get that connector off the pcb and ideally replace with a new one, but you might be able to get away with reusing it if it looks ok. But i strongly recommend a new one.If the TH legs are not soldered i would be tempted to bend them inwards so they don't touch the sides of the hole.That way the connector can simply be lifted off the board once all the solder melts.I wouldn't use hot air for this (unless you have a preheater). It's too easy to rip up a track because you're not heating it evenly. Tracks are much easier to rip off when there has been force applied to a connector that has cracked solder.The way i would do it with the gear i have is to put the board in a reflow oven and get the entire PCB up to solder temp.Then i would open the door, carefully pull out the tray and very very carefully remove the connector with two tweezers. One holding the pcb and one lifting the connector.If using a oven you will have to sort out how to hold the pcb so you dont melt any connectors on the under side.What i mean is, if the oven wire rack is touching a connector on the under side the plastic will be super soft and it will bend the connector. So you have to make up some spacers so its resting on the PCB FR4.There is also a risk the PCB may warp/bend when heated.

author: rx8pilot
author_rank: Super Contributor
timestamp: September 09, 2019, 01:08:34 am
content: I am drawing up a custom aluminum tray that will guard the connectors. I can do a controlled pre-heat in the convection oven and then use two hot-air systems (and a lot of flux) to bring it to the melting temp.Still thinking that through.As for a brand new connector, there is a huge lead time so I am highly motivated to protect and use the original if at all possible.Typet purly on my fone.EDIT:I have a Haas CNC machine which makes custom fixturing and trays a simple affair.

author: rx8pilot
author_rank: Super Contributor
timestamp: September 09, 2019, 04:30:19 am
content: Here are the masking fixtures I am machining to protect the connectors. 6061-T6.The plan is to put the PCB in the fixtures and bring it up to about 210C in the batch oven and then pull it out and use two air systems - one on the bottom and one on the top to get to flow temp. Going to attempt laser cutting a stencil with my CO2 laser (not sure how well that will go). At least the final solder will be done with leaded solder so the temps will be lower.

author: Zucca
author_rank: Unknown
timestamp: September 09, 2019, 09:07:07 am
content: I would buy a bunch of those connectors and make some PCBs to play with them.Once you are confident with your process then move on with the $150K golden one.BTW having spares connectors could save you in the future.Are those not available anywhere?

author: Psi
author_rank: Super Contributor
timestamp: September 09, 2019, 09:53:14 am
content: Quote from: rx8pilot on September 09, 2019, 04:30:19 amYou can get a laser cut stencil for like $20 from any PCB place online, why try to make one yourself?You can cut it to size with a pair of scissors easy enough.

author: Rerouter
author_rank: Super Contributor
timestamp: September 09, 2019, 10:06:59 am
content: You have 2 beautiful screw studs to mount a thermal gaurd plate, I would fit a sheet of metal mounted on them, and kapton tape between the board and guard to prevent any cross flow of heat,Preheat the board to something like 130C, even better if you have something from underneath to keep it toasty,Then just go overkill on the existing connectors, melt them off if you have to,Once removed, clean back the board with wick, tin any pads, lay down some flux, get the area hot enough that the solder begins to flow on the pads, switch to heating with the hot air from the underside, and place down a new replacement socket, nudge it lightly until you see it drop on both sides, give it a few more laps with hot air underside with some more nudges, then you should be set.For those bigger center connectors, as long as you keep to one of the edge connectors at a time they should be fairly steady as the other half of the connector should be holding it in place.Edit, OK now I see the 2 giant connectors on the other side, this makes things harder. when it comes to direct underside heating... your going to have to go a bit warmer than I would normally on the board, and may be worthwhile preheating the new connector before placing it, this way it doesn't immediately freeze the joints.

author: amyk
author_rank: Super Contributor
timestamp: September 09, 2019, 12:04:29 pm
content: Quote from: rx8pilot on September 09, 2019, 12:30:50 amIf enough of these same boards come to you with the same defect, maybe it's worth reverse-engineering and making your own... from what I see, it only contains a few passives and connectors. Perhaps you could even improve on the existing design so that those joints don't crack as easily...

author: Renate
author_rank: Super Contributor
timestamp: September 09, 2019, 07:19:07 pm
content: It may not be applicable to this case (if you can't get a new connector),but I always try to destroy the old part to protect the PCB even in trivial cases (like an 8 pin DIP).I'd take a Dremel cutoff disk, chop up the connector and remove the pins one by one.

author: rx8pilot
author_rank: Super Contributor
timestamp: September 09, 2019, 07:48:02 pm
content: Quote from: Renate on September 09, 2019, 07:19:07 pmIt may become the only option. The lead time on these is fairly long but I have a good relationship with Samtec - they may have some sample qty's available if I am lucky.Typet purly on my fone.

author: rx8pilot
author_rank: Super Contributor
timestamp: September 16, 2019, 04:31:18 am
content: This project saw some success today! I will say it was the most anxious I have ever been soldering anything. The cost of failure was rather extreme by my standards.In the end, I elected to design and machine two special fixtures that would hold the PCB, provide thermal protection for the existing connectors, and provide a way to apply heat safely. Certainly the first time I have ever machined parts to solder a single connector. Lots of consideration and half a day at the CNC - it was game time.I put all the parts in the convection batch oven and pre-heated at 100C for about an hour followed by 150C for 5min and 200C for 3min. At that point, I transferred the fixture to the bench where I had a special holder ready and 2 hot-air systems. One hot air was setup to heat from the bottom of the PCB, the other was handheld and focused on the work area. All was being watched with a microscope so I could see the moment the solder melted. Lots and lots of tacky flux was pumped in and I kept some motion on the hot air nozzle to avoid melting the connector.Initially, I was planning to remove the connector, clean the pad/pins, stencil paste, and re-flow. Once the original solder flowed, I decided not to remove the connector and see how it looked. With all the flux, the solder wicked nicely on the connector pins leaving a nice fillet and a shiny finish. At that point, I decided not to remove it and examine the result more closely. After a clean-up and examination under the microscope - all pins flowed and looked great.The fixture protected all the other connectors well and the end result looks like a brand new board. What a challenge. It was fun.

author: Psi
author_rank: Super Contributor
timestamp: September 16, 2019, 04:35:53 am
content: Out of interest, are you trying to fix for someone else or do you get to keep it

author: rx8pilot
author_rank: Super Contributor
timestamp: September 16, 2019, 04:46:37 am
content: I definitely do not get to keep it. The owner is paying for the effort so once it is back together and tested, it will go away. I should say that even after this part was repaired, the project is not out of the woods yet. The re-assembly is rather delicate with the image sensor being particularly so. I would estimate that the sensor PCB is worth $60-$80k or so.Gotta be careful.Typet purly on my fone.

author: rx8pilot
author_rank: Super Contributor
timestamp: September 18, 2019, 12:37:30 am
content: The camera is back together and appears to be working. Lots of tests need to be done, but this is solid progress.

author: Bobertsawesome
author_rank: Regular Contributor
timestamp: September 19, 2019, 08:40:42 pm
content: I would be shitting myself having to work on that thing being the cost. Good job on getting it running.

author: rx8pilot
author_rank: Super Contributor
timestamp: September 19, 2019, 08:49:09 pm
content: Quote from: Bobertsawesome on September 19, 2019, 08:40:42 pmI am not saying that did not happen.........

author: Psi
author_rank: Super Contributor
timestamp: September 19, 2019, 11:42:20 pm
content: I hope you billed them a sizable amount. The repair cost should carry a premium for something so expensive, even if the actual repair process wasn't that hard.Lots of extra care and attention had to be taken and extra stress etc..

author: Dubbie
author_rank: Unknown
timestamp: September 19, 2019, 11:59:36 pm
content: Nice work rx8!Love to see some custom made tooling!

author: Mr. Scram
author_rank: Super Contributor
timestamp: September 20, 2019, 02:01:33 am
content: Quote from: Psi on September 19, 2019, 11:42:20 pmExcept that it was hard. Milling custom brackets on a CNC machine that you happened to have into your garage isn't everyday fare. Lots of high dollar investments and a highly varied skill set are required.

author: rx8pilot
author_rank: Super Contributor
timestamp: September 20, 2019, 04:09:16 pm
content: Quote from: Psi on September 19, 2019, 11:42:20 pmThe agreement was fair, I think. Essentially I based the fee off of a bench technician and machine shop rate to cover the time and materials needed to attempt the repair. If the repair was not possible, that would be all I charge. If I fixed it, however, the rate tripled to cover the value of having a unique setup and skillset to make this happen.That arrangement was great for me and the owner of the camera.

author: Psi
author_rank: Super Contributor
timestamp: September 21, 2019, 09:51:31 am
content: Quote from: Mr. Scram on September 20, 2019, 02:01:33 amIt sounded a lot more like a very careful and time consuming repair job than a hard repair job.

author: rx8pilot
author_rank: Super Contributor
timestamp: September 21, 2019, 05:01:16 pm
content: Quote from: Psi on September 21, 2019, 09:51:31 amYes, exactly. It was all physical/visible failures so diagnostics were not a challenge. Just look through a microscope and that is it. This was all about being slow and methodical in the process of figuring out how to repair it.The previous Phantoms I have worked on needed component level diagnostics and repairs. SDI drivers/receivers and numerous components related to power management and PDN.

author: TiN
author_rank: Super Contributor
timestamp: September 21, 2019, 05:20:40 pm
content: Thanks to you and to owner for sharing the story.

author: rx8pilot
author_rank: Super Contributor
timestamp: September 21, 2019, 05:25:14 pm
content: Quote from: TiN on September 21, 2019, 05:20:40 pmI recorded video of most everything and trying to cut a YouTube video for those that are curious how it all went.

author: richnormand
author_rank: Unknown
timestamp: September 21, 2019, 08:32:16 pm
content: Excellent work there, interesting post indeed.I have come across similar issues with bad geometries for the soldering iron or using hot air pencils that could damage other stuff around.I rigged my stereo microscope with a micrometer x-y stage and z adjust to get a stable fix on the area. I keep around an old Pace SensaTemp PS90 soldering iron for these jobs.This uses solid 1/8" diag (or so) tips that are held with a side set-screw. It is then easy to machine a soldering tip out of a solid copper rod with all the right bends, size, diameter and curves to reach the area to be repaired.Flux and pre-tin the resultant tip, check temperature and apply to spot to be done. Used aluminium foils with one adhesive side and kapton tape on surrounding devices.I have done this 8 or 9 times over the years with very good success and no collateral damage on LN2 IR detectors, EDX and microwave stuff.

author: cgroen
author_rank: Unknown
timestamp: September 22, 2019, 08:28:03 am
content: Quote from: rx8pilot on September 21, 2019, 05:25:14 pmNice! I'm often checking your channel for new stuff, will be looking forward to some more great stuff from your workshop!