Seek Thermal Compact Pro broken sensor wire - Page 1
Forum section: electronics / general

author: metaxa929
author_rank: Newbie
timestamp: October 31, 2022, 12:01:21 am
content: Hi!I have Seek Thermal Compact Pro. Trying to wipe by soft brush, the (mostly imaginery ) dust from bolometer sensor, trough previously dismantled the lens and slide the calibrating flag. And... stupidly (forgot about them) has jammed and shortened golden wires that connect bolometer to PCB. By needle i straightened as i can those wires , resolve shortage, but one wire has broken. Right near welding "ball" on bolometers pad.Theoretically, it can be soldered, but I'm in doubt about repair method.I nave JBC NT115A nano solder iron tool with c115-124 cartridge (0.1mm bent cone tip).But I am not sure whether it will be possible to solder this soft, loose wire. I mean surface tension of liquid solder will pull the wire (real soft) by iron.And another aspect - I'm not sure, how bolometer withstand heating during soldering process ?As alternative method - place on wire break point little amount of solder paste and heat it up by hot air.... and I'm afraid to heat it up even more than if it by iron tool.So here the question - assuming that microbolometer is fragile MEMS, under vacuum and so on, can i heat it up without any damage and loosing its specs?What maximum temperature will be safe?Unfortunately i have no success seeking microbolometers specs.Any help?Thanks.

author: Fraser
author_rank: Super Contributor
timestamp: October 31, 2022, 03:34:29 pm
content: Whilst the microbolometer is thermally relatively robust, soldering those fine and brittle wires would normally be considered almost impossible with conventional soldering tools. I say “almost” as I am sure that some micro soldering professionals might be able to do it!The use of solder paste is an interesting idea but you will need very fine grade paste and careful positioning of the wire.I wish you the best of luck soldering that bond wire, it will not be an easy task. It is your only chance of recovering that microbolometer though so you have little to lose.I did consider the use of good quality Silver loaded paint in place of soldering but there is the potential to cause shorts through paint spreading and it is not the most mechanically strong bond.Fraser

author: metaxa929
author_rank: Newbie
timestamp: October 31, 2022, 10:23:22 pm
content: Thank you for your support and wishes!Can I infer from your answer that heating with hot air to around 280-300 Celsius degrees would be safe for a microbolometer?I think, if an air heating is relatively safe, maybe for further safety, I should use Rose's alloy? Rose's melts at something around 100 Celsius.Glue a tiny piece of Rose's alloy onto a quality flux, say Ersa FMKANC32, to the point of soldering, and then warm with hot air? ..

author: Fraser
author_rank: Super Contributor
timestamp: October 31, 2022, 10:46:05 pm
content: I was thinking of a hot air pencil for this type of work. I own OKI and PACE hot air pencils that would be safe on the contact strip of the microbolometer as they have very small 2mm nozzles. Heating the whole microbolometer might cause issues with the fixing system used to bond it to the PCB. The Microbolometer contains a vacuum (no air expansion issues) and is unlikely to delaminate, but care is still needed.Low melt point solder is an interesting idea. I have seen types that melt at temperatures as low as 60 Celsius. The down side of such solders is that they are very brittle. That may not be an issue in this use scenario though. I have never used such very low melt solder for soldering so cannot comment on how well it will flow and solder the bond wire to the pad. Some experimentation on some scrap material to assess how it behaves.I do not envy you doing this repair and sadly bond wire repair is not something I have ever attempted.Good luckFraser

author: Fraser
author_rank: Super Contributor
timestamp: October 31, 2022, 10:52:11 pm
content: Very low melting point solder alloys…..https://www.indium.com/blog/a-guide-to-low-temperature-solder-alloys.phphttps://www.amazon.co.uk/Gaugemaster-GM01-Melt-Solder-Degrees/dp/B01MFC5X6X/ref=d_pd_sbs_sccl_4_1/257-3072814-1846965?pd_rd_w=6ABCJ&content-id=amzn1.sym.a0b3831c-e4a4-4b9c-9a28-e04b8e3b1f51&pf_rd_p=a0b3831c-e4a4-4b9c-9a28-e04b8e3b1f51&pf_rd_r=DRX694RNT34R2VF5YKCE&pd_rd_wg=nZwbl&pd_rd_r=bcf8f423-7280-43cd-8b8c-8a7cddf5a936&pd_rd_i=B01MFC5X6X&psc=1

author: Fraser
author_rank: Super Contributor
timestamp: October 31, 2022, 11:00:44 pm
content: https://www.indium.com/applications/pcb-assembly/low-temperature-soldering/

author: metaxa929
author_rank: Newbie
timestamp: October 31, 2022, 11:33:21 pm
content: Very interesting and useful tables, thank you!As i knew, most of low melt alloys contains toxic cadmium, like Wood's alloy with ~60 celsius.But as i see in your tables there is some positions without cadmium..Need to dive into it !Yes, I'm also in doubt about fluidity and ability of low temp alloys to make good solder connection.Will think about making some test soldering before repair my wire.The greatest doubts are caused by the fact that the microbolometer contains delicate fragile mechanical structures.Can they deform when heated?Good wishes,Andrew

author: dennis1573
author_rank: Contributor
timestamp: November 01, 2022, 09:32:28 am
content: A while ago, i saw a review of a JBC soldering station and the guy said bonding pads desolve if you try to solder them.I never had to do any bondwire repair, so i dont know.Just something i remembered from that video maybe it helps...https://youtu.be/2vpTYaDGmCs?t=1587

author: Fraser
author_rank: Super Contributor
timestamp: November 01, 2022, 11:13:44 am
content: dennis1573,Well spotted and thank you for sharing the video link.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: November 01, 2022, 11:26:43 am
content: With the risks of soldering the bond wire, I had a very quick Google search for bond wire repair and found something applicable and useful to this microbolometer repairhttps://youtu.be/1-b5WQZVnB4It looks like the silver loaded glue is the way to go. Steady hands and a decent microscope will be essential !Fraser

author: Fraser
author_rank: Super Contributor
timestamp: November 01, 2022, 11:56:10 am
content: I have done some searching on eBay for conductive glue, adhesive and paint. There are many advertisers of such products with low prices for 0.2ml BUT I have no information on the quality or performance of these products so some caution and testing is advised. I used to use silver loaded paint and it was an excellent performer, though quite expensive at around £12 for a small vial. If you buy something very cheap, it may not contain a high proportion of silver particles so please buy with caution.I tend to trust the Polish company Technicoll product detailed below as they have produced products that I use and find to be of good quality…..they even state the resistance for their product which many do not.https://www.ebay.co.uk/itm/262247283610?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=mlPRn_SYSoq&sssrc=2349624&ssuid=BgpdXaaLSkK&var=&widget_ver=artemis&media=COPYThe price for this product is reasonable and I have just bought a vial of this silver loaded paint/glue for my “just in case” stockYour question has reminded me of how useful conductive paint/glue can beIt will sit in my PCB repair kit along-side my ‘Z’ axis double sided conductive tape

author: Fraser
author_rank: Super Contributor
timestamp: November 01, 2022, 12:32:07 pm
content: It would appear that using a conductive adhesive is a tested method of bond wire repair…..https://ieeexplore.ieee.org/document/8509620Fraser

author: Fraser
author_rank: Super Contributor
timestamp: November 02, 2022, 02:23:45 pm
content: Excellent service from the seller of Silver loaded glue/lacquer, it arrive todayI attach images of the product and packaging to give more detail of its use. Looks perfect for the microbolometer bond wire repair. Not too thick and not too thin. This looks just like the product I bought 35 years ago and I still have that in my specialist repair tools box. It is still good after all these years which amazes me. I thought it time to buy some fresh stock thoughFraser

author: Fraser
author_rank: Super Contributor
timestamp: November 02, 2022, 02:34:10 pm
content: And just to prove that I still have my original Silver loaded glue/lacquer from 35 years ago ! Picture attached. I originally bought it to repair the rear window heated strips on my car. I think I bought it from Radio Shack when they were still a half decent electronics company. Back then it was considered an expensive specialist product at around £12 but it has certainly lasted wellYou do not need much for many repairs so it does tend to last. The polythene cap split around the top edge at some point so I used my soldering iron to plastic weld it. That repair has lasted as wellGreat stuff to have for those challenging situations where soldering a bridge wire is not possible and only low currents are involved.I just remembered, I used this lacquer to repair the corner of a multimeter LCD panel that had cracked. I repaired the cracked area with glass glue and used the silver lacquer to bridge the crack at each Zebra strip trace. That meter worked for many years but I recall I binned it in my last clearout, so cannot show it here.Fraser

author: metaxa929
author_rank: Newbie
timestamp: November 03, 2022, 12:37:07 am
content: Hi Fraser!You are great, and done great job ! Thanks for information!I disassemble my thermal camera again. Look at that damn wire), take couple of photos.Now, the end of broken wire located slightly above the ball (little gap between them), almost parallel to contact pads panel.Oh.. I think it near to impossible to solder that wire..What about silver-filled glue, it seems like real solution. Now in my hand is that glue. As in your case, it for auto rear window heater strips repair.But in my case it looks too thin. Almost like water. Stated as "containing metal powders silver, gold, platinum, palladium" Hmm .. Don't know about palladium, rather seems like aluminum paint) .I tested it, drawing some lines on the plastic film. After about 30 min, painted trace become quite conductive. Looks promising, but that glue almost not forms a layer or drop (ball). I doubt that can be used for repair. If only try to apply repeatedly...If I left the vial opened, maybe the glue will evaporate solver and tend to thick..What kind of your glue? Is it solver based or epoxy resin?Best regards,AndrewPS.. to make it clear... broken wire is 14th from left, not 13th, as stated on first picture

author: Fraser
author_rank: Super Contributor
timestamp: November 03, 2022, 09:51:32 am
content: Did you shake the silver glue well before testing it. The solids settle out and it needs a really good shake to get the the glue to thicken. As you say, you could take a little of the glue and allow it to thicken in the open air before using it. I do not know what solvent carries the conductive glue but it is slow to evaporate so not very volatile. I will see if I can find the safety sheet for the glue I purchased.Fraser

author: bostwickenator
author_rank: Contributor
timestamp: November 06, 2022, 01:18:10 am
content: I did the exact same thing but broke 5 wires. Ended up trashing the unit. I understand these are ultrasonically welded in factory not soldered. The silver epoxy is definitely your best bet.

author: gabiz_ro
author_rank: Regular Contributor
timestamp: November 06, 2022, 07:09:34 am
content: Too bad you trashed.Last chance attempt it would be to broke them all,clean area and try to use some zebra gold elastomeric connector mechanically fixed somehow in place.

author: metaxa929
author_rank: Newbie
timestamp: November 06, 2022, 09:49:25 pm
content: Hi, brother in misfortune )Yes, after studying the information kindly delivered by Fraser, i see that using of the silver -filled glue is most reliable way to go.

author: metaxa929
author_rank: Newbie
timestamp: November 06, 2022, 09:56:07 pm
content: gabiz_ro,Hm.. Very interesting!Indeed, there are flexible "rubber" connectors! Why didn't this cross my mind?

author: Bill W
author_rank: Super Contributor
timestamp: November 07, 2022, 12:26:11 am
content: Zebra etc usually need a bit of force to get connected, so not sure if the remaining bond wires from the sensor end would provide that

author: gabiz_ro
author_rank: Regular Contributor
timestamp: November 07, 2022, 07:01:07 am
content: It is silicone core wrapped on three sides with very thin stripes of gold wires.Not the ones with carbon (graphite)Solution was far bostwickenator cases.