Would you do this? weighing possibly dumb idea. - Page 1
Forum section: electronics / general

author: cdev
author_rank: Super Contributor
timestamp: June 18, 2017, 07:30:31 pm
content: Awhile back I posted about cleaning an antenna tuner I bought some time ago for cheap. Its got a lot of black gunk in it and Ive gotten pretty far in cleaning it but there are two points on the roller inductor which contain ball bearings and I cant really clean in there enough.I have this ultrasonic mister - its a prop for Halloween. What I am wondering if I should do is just briefly, see if I can use the mister as an ultrasonic cleaner to "get the gunk out" using "citrus solv" which is a citrus degreaser I have which seems to be safe for electronics. (Ive used it with PCBs)Ive already wasted a huge amount of time on this thing. For a while I had the inductor totally (the entire length) under 0.2 ohms but then I foolishly tried to get more black gunk out of the roller bearings and that seems to have ruined it again, and now the black gunk is semi liquified and wont stay where it was before with the ball bearings, its getting onto the brushes that need to stay clean to make the thing work.Well, it will be interesting, at least. I am doing this in the kitchen so I have around one and a half hours.This trying to measure very low ohms without the measurements jumping around has really made me see the value of having a good collection of nice, premium multimeter leads, including ones with super solid, preferably gold banana plugs you can easily solder onto things..Note to self, buy some.Yes, an antenna tuner is also valuable for receive, not only that, the cleaner it is the better and you really notice the difference as it gets cleaner.

author: German_EE
author_rank: Super Contributor
timestamp: June 18, 2017, 07:35:59 pm
content: Cover the black gunk in acetone (NOT nail polish remover as this has oils in it) till it dissolves awayThen clean off with lots of isopropyl alcoholThen clean off with distilled or de-ionized water and dry in warm airThis should cure your gunk issue.

author: cdev
author_rank: Super Contributor
timestamp: June 18, 2017, 07:41:39 pm
content: Ahhhh.. I previously used nail polish remover to try to get it out, did not seem to help like I was hoping it would. Outcome was problematic..maybe I should wrap it up where I am now and wait for another day, I just got the signal that my time window for use of the kitchen isnt so large.the tuner is an MFJ brand and the gunk is some kind of grease mixed with graphite that they swear by but others swear at.I got an old but still very functional >$200 "full legal limit capable" tuner for a bit over $60 which will be nice when I get my ham ticket, so I shouldn't be complaining.

author: Cerebus
author_rank: Super Contributor
timestamp: June 18, 2017, 07:59:54 pm
content: Quote from: cdev on June 18, 2017, 07:30:31 pmBeware, "citrus solv" to me implies limonene. Limonene is an excellent solvent for degreasing, however it is also an excellent solvent for many plastics, including ones that would normally be unfazed by acetone or alcohol.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: June 18, 2017, 09:36:31 pm
content: Quote from: cdev on June 18, 2017, 07:41:39 pmMost remover is acetone-free these days.

author: cdev
author_rank: Super Contributor
timestamp: June 18, 2017, 09:53:28 pm
content: What do people use in ultrasonic cleaners to remove greases? (I dont know if its petroleum or silicone based grease I am dealing with)

author: Gregg
author_rank: Super Contributor
timestamp: June 22, 2017, 03:49:56 am
content: I would bet your grease is petroleum based rather than silicone. Silicone doesn’t tend to dry out as much as it tends to creep away and cover everything it can. A lot of older petroleum based greases become hard over long periods of time when exposed to air. Some of the hardening is due to evaporation of the more volatile petroleum components. Some is due to polymerization and some is oxidation of the metal salts used to stiffen the grease. Hopefully the modern synthetic based greases live longer. There is also a chance the black stuff is molybdenum disulfide rather than graphite and is even nastier to get totally clean.The best bet is to try and get the petroleum component back into the mess and dilute it. Fast evaporating solvents are fast at dissolving things but evaporate away too quickly. They are great for the final cleaning stages or if you can immerse the tuner fully for several days without harming anything (not likely). My personal recommendation is to put it in a suitable zip lock bag and add paint thinner (mineral spirits) (available at Home Depot, Lowes etc. for reasonable prices) fill it part way and shake it at convenient intervals for several days. Then pour off the black goop, scrub what you can with an old tooth brush and an old paintbrush. A cheap paintbrush with the bristles trimmed short makes a wonderful scrub brush; the shorter bristles are stiffer. Repeat as necessary. Keeping the bag sealed keeps the vapors in contact with the parts.The cheapest solvent around is gasoline and I’ll probably get flack for mentioning it. But if you are careful and it doesn’t attack anything you value, it is hard to beat the price.Most ultrasonic cleaners are used with non-foaming detergents and water. Dishwasher detergent can be used on some things but some of it may be too alkaline for aluminum. Ultrasonic can also cause things to loosen and dissolve due to cavitation, which is how they work.

author: Cerebus
author_rank: Super Contributor
timestamp: June 22, 2017, 10:22:20 am
content: You missed out good old paraffin/kerosene.

author: CJay
author_rank: Super Contributor
timestamp: June 22, 2017, 11:08:14 am
content: At risk of provoking a storm of criticism, I've cleaned electronics in a dishwasher more than once or twice, I've also doused it in foaming cleanser and scrubbed it.A lot of people recoil in horror but it works, what's important is how you handle it after the cleaning, you need to flush it with Isopropyl to absorb the leftover water and wash off the residue of the detergents, once you've washed it down you need to dry it thoroughly before use.(Foaming cleanser is a good way to get rid of the tobacco smoke residue that so many radio operators destroy their radios with)Something 'simple' like an antenna tuner would be really simple to clean that way, just remove meter movements and switches if you can't guarantee you won't get the liquid into them. May need to lubricate the spindles/bearings afterwards

author: Cerebus
author_rank: Super Contributor
timestamp: June 22, 2017, 02:10:31 pm
content: Quote from: CJay on June 22, 2017, 11:08:14 amS.O.P. in some places when you need high surface resistivity/low leakage on a board. Just make sure you rinse thoroughly in deionized water and ideally bake the board dry at around 50 C overnight. Pease approved, if I remember correctly, and you can't get any better than that.

author: tronde
author_rank: Frequent Contributor
timestamp: June 23, 2017, 12:21:32 am
content: Quote from: cdev on June 18, 2017, 07:30:31 pmWhy not show us a couple of pictures of the tuner? In the other thread you say you got information about the grease. Tell us more.

author: cdev
author_rank: Super Contributor
timestamp: June 23, 2017, 02:43:02 am
content: Okay,photos below..At this point it looks good physically, much better than it did when I got it, but every time I clean it with IPA, I still get black gunk... so its time for a better degreaserIve used a lot of paper towels, Q-tips and toothbrushes.. turning them black in the process..but there still are gaps when the roller spins around,I bought what appears to be an industrial strength degreaser from Home Depot which I may try applying tomorrow. I have some toss away paintbrushes which I am hoping will work better than toothbrushes and a metal container which can be used to immerse one side of it at a time in a solvent bath after its removal if thats needed.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: June 23, 2017, 03:21:22 am
content: Yes, the pictures would help a lot. What types of plastics or O-rings are in this assembly?One method that I've used on mechanical devices, not really for electronics but in your case it might work, is automatic transmission fluid. Something like basic Dexron III. It can really pick up materials and a lot of greases. If the contact is required to be clean afterwards, then the transmission fluid will be relatively easier to clean out. Brake cleaner perhaps? That's why it's important to see what kinds of plastics are in there, to make sure they don't get melted or dissolved.

author: cdev
author_rank: Super Contributor
timestamp: June 23, 2017, 04:54:40 am
content: The brush/contact area seems to be the source of the problem. And there still is grease in that hole, which I'm having a hell of a time with. Going to remove the inductor tomorrow so I can immerse that area in degreaser.Its going to stink like crazy. I hate those solvents, the smell often gives me a major headache..

author: technogeeky
author_rank: Frequent Contributor
timestamp: June 23, 2017, 04:59:01 am
content: This might be the single cleanest thing I've ever seen described as "dirty" on this forum!

author: cdev
author_rank: Super Contributor
timestamp: June 23, 2017, 03:22:34 pm
content: This is what's happening, this is taken as I rotate the inductor crank.I should be able to isolate and fix the problem today, with a little luck.This is with the sensitivity turned up a bit higher than optimal so you can see the roller cutting in and out. This is receive only so far, I need to get my ticket and get a rig set up to use the tuner, but I can't even think about using it for anything like that until this problem is fixed.The picture above of the bearing doesn't really tell the story, although it hints at it, because it shows how the black gunk comes out of the well where the roller bearings are, even right after its been cleaned. I had the issue under control briefly but for better or for worse, I stirred it up again, by trying to clean it a bit more, and since there still was black gunk in there, then the problem came back.Whatever was in the lubricant they used (some carrier and graphite) its usefulness is "debatable" to put it kindly..

author: CJay
author_rank: Super Contributor
timestamp: June 23, 2017, 03:47:24 pm
content: It's been bugging me and I've just realised why.You shouldn't be making contact through the bearings, the leaf spring I've arrowed in the picture should be the contact for one end of the coil and the other contact is the roller.Careful removal, cleaning and retensioning that spring and its contact areas should be all you need to do, *maybe* light abrasion of the slot it sits in on the shaft as well.

author: tronde
author_rank: Frequent Contributor
timestamp: June 23, 2017, 05:05:17 pm
content: I agree with CJay.If you really want to clean the bearings, you can use brake cleaner spray with an extenson tube. You have no fragile plastics in that area to worry about.If you need to clean dried oil or fat and must be careful because of any syntetetics, the Printer66 from Kontakt Chemie has been quite efficient.http://uk.farnell.com/kontakt-chemie/printer-66-200ml/cleaner-printer-66-200ml/dp/801033Don't know if it is sold outside of Europe (Kontakt Chemie is part of CRC Industries) , but I guess something similar is available as long as dot matrix printers are still in use.

author: cdev
author_rank: Super Contributor
timestamp: June 23, 2017, 07:36:46 pm
content: The plot thickens.Taken as I crank.This is around 16 MHz of spectrum. Low frequencies are on the left. Its all reasonably clean now.Seems like there might be a crack somewhere? Trying to find where it might be or if that is the problem.I'm going to try retouching some of the solder joints.

author: cdev
author_rank: Super Contributor
timestamp: June 24, 2017, 02:44:59 am
content: So, status report, that was it. Tiny crack in the solder connecting roller winding to shaft. And now its fixed, I used my big-old el-cheapo Harbor Freight soldering GUN so it could "meld" properly and it did, and now its electrical connection is perfect plus its crank and roller wheel are well lubricated with literally one drop of lithium grease that arrived today, (the special small tubes for garage door openers, "Genie" = small tubes of lubriplate) and poof, silky smooth. Nodropouts at all.Ohms all well under one ohm!Now I can get my ticket and use this tuner the way its meant to be used. Next on the to-do list -I have to hunt down the source of and get rid of the horrid (SMPS???) noise pictured..

author: CJay
author_rank: Super Contributor
timestamp: June 25, 2017, 09:35:06 am
content: Excellent result and a nice piece of equipment to add to your station. Plans afoot here to resume my path to the licence in a fortnight so maybe one day on air?The noise could be from anywhere, I had terrible noise coming from a 12V mains adapter and various CFLs around my home, some reasonable quality LED E27 bulbs solved the CFL problem and the undercabinet LED strips now have a spare bench supply running htem until I get around to fitting the much better quality SMPS i lucked into recently.

author: cdev
author_rank: Super Contributor
timestamp: June 26, 2017, 03:48:21 am
content: Cjay,It's like night and day.The improvement is really dramatic.Also, because the noise went down, perhaps, suddenly I have a new hot clue as to the age old SMPS-like noise problem I have..in that the frequency seems to be modulated by my hands being on or off the keyboard, it slightly changes by touching certain bits of the wiring around my computer but I still have not localized exactly what the source of it is.But that means the end is in sight, whatever it is its under my control, and not at a neighbors- wow that will be big.The noise is affected by the KB but not produced by the keyboard because even if I unplug it, its still there.