Help!! Candle wax dripped into Audio Receiver! - Page 1
Forum section: electronics / repair

author: MunsterAbu
author_rank: Newbie
timestamp: December 30, 2022, 02:21:55 pm
content: Hi,As you can see in the photo, candle wax has dripped into an audio receiver (a Sony STR-DN1080).What should I do?!The receiver is working fine. I am tempted to leave the wax there. I am afraid that if I try to remove it, I will break something.If I leave the wax there, is there a danger of components overheating? Is there a fire risk?Any advice wouid be much appreciated. I don't know anything about electronics!Thanks.

author: RoGeorge
author_rank: Super Contributor
timestamp: December 30, 2022, 02:41:07 pm
content: Remove it with care, piece by piece, I don't think anything will break. Maybe heat the PCB but only a little, on the downwards side to soften the wax at the contact surface.If you let it there and something goes wrong with the receiver, that wax might become a fire hazard. Instead of only smoke and a burnt component, that wax might start a fire, with droplets in flames dripping outside of the case.

author: MunsterAbu
author_rank: Newbie
timestamp: December 30, 2022, 02:53:06 pm
content: Thanks for that.Some wax has also dripped down to a board underneath (see photo), so I think the top board will need to be removed, which is very scary to me. I think I might need to find a local electronic repair shop and not try it myself.By the way, if I was to try it, how would I heat the PCB?

author: pcprogrammer
author_rank: Super Contributor
timestamp: December 30, 2022, 02:56:46 pm
content: I would not use a mechanical removal method. Probably best to use hot air just above the melting point (Somewhere between 40 to 70 degree Celsius) and let it drip of the board and use paper towels to clean as gently as possible. After most of it is gone use some Isopropyl alcohol to clear the board and let it dry.You can try with a hair dryer but don't heat to long on a single point. Feel with your fingers if it is not getting to hot.Trying to remove the wax with tools might damage components or rip them of the board by accident.

author: Ian.M
author_rank: Super Contributor
timestamp: December 30, 2022, 03:23:19 pm
content: The problem with melting the wax is that it risks it forming a film inside the ribbon cable connectors that will be very difficult to remove and will cause bad connections. I suggest softening the wax round the connectors with hot air and peeling as much as possible off the connectors and cables *without* digging down to the PCB or trying to peel it off the board, which as Pcprogrammer points out, is risky to small SMD parts. Then, if you aren't willing to risk dismantling to melt the wax free from the back with the board upside down so it drops off in large pieces, you can protect where the cables enter the connectors with tape, orient the board heatsink side down, with foil over the heatsink so it doesn't end up coated with wax, and melt the wax off the board as suggested, starting furthest away from the connectors. Blot off as much melted wax as you can, but traces of it under and round components can be left, rather than risking aggressive cleaning. Isopropyl alcohol wont be much help removing melted wax but could be helpful peeling softened wax.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: December 30, 2022, 03:28:25 pm
content: You could just leave it alone. Lots of radios have lots of wax on their boards to keep components physically and thermally stable. Also wax is used to keep adjustable transformers and coils from slipping. It is quite good for these functions. It does not hurt anything. It is non conductive. The wax used in very old tube radios is still intact after 80 years, that wax is probably Bee's wax. I use any candle wax for adjustable transformers etc. all the time. To readjust I just heat it up with soldering iron, or hot air, the wax "lubricates" the adjustable slugs and prevents them from locking up.If the radio works, I would leave it alone.Just check to see if it heats up and melts. I don't think it will.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 30, 2022, 03:43:02 pm
content: If it doesnt create problems, i would leave it as it is ... but heating it could be problematic or not, sometime it will pop with an finger nail push, or with an air dryer, just a little heatyou could be able to roll it, while removing itI used a trick to heat the wax to almost liquify it and push some sponge paper to absorb it ??my 2 cents

author: MunsterAbu
author_rank: Newbie
timestamp: December 30, 2022, 03:54:35 pm
content: Great replies. Thanks. Keep 'em coming!The preferred solution is to leave it alone, obviouslyso it's great to see a couple of votes for that!

author: pcprogrammer
author_rank: Super Contributor
timestamp: December 30, 2022, 04:22:21 pm
content: Good point from Ian.M about the connectors.Leaving it alone is an option, but looking at the picture shows a dent in the wax above a big chip indicating it might get hot enough at that point when in operation. Freeing that chip might be better for the chip in the long run.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 30, 2022, 04:56:16 pm
content: yep if the chip heat the wax enough to create some "goo" i would try to remove itIt will be an endless loop of melting and hardening ... and the power board / amplifier board is under it ...

author: wasedadoc
author_rank: Super Contributor
timestamp: December 30, 2022, 05:05:26 pm
content: You might find that freezing the wax causes it to become both brittle and less adhesive enabling you to carefully remove it in pieces.Wrap the receiver in a plastic bag before placing in your freezer. After several hours remove and unwrap. Be aware that condensation will form. Do not reassemble and operate until ALL of it has evaporated.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 30, 2022, 08:06:54 pm
content: One should at least remove most of the wax. The way layer makes the circuit below run hotter and there is a slightly increased fire hazzard.Getting the wax warm and soft and a wooden scraper / tool (e.g. similar to the stick in ice cream) should get the bulk of it. Wood is slightly conductive and this way a poor mans / makeshift anti-static material.Away from the connectors one could than go all the way to liquid and use paper towel to absorb. There is no need to get it super clean.

author: Bud
author_rank: Super Contributor
timestamp: December 30, 2022, 08:14:36 pm
content: What is the deal with fire hazard, wax was used for decades to seal adjustable inductors and mains transformers.Edit : @OP i would remove the was from the IC tops and leave everything else.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: December 30, 2022, 10:30:10 pm
content: If you decide to remove it, or some of it, I really like the freezer approach.I ususlly end up digging the stuff out if I have to replace a part though.I have left it alone on connectors does not seem to hurt at all. Makes them easy to connect and disconnect.

author: John B
author_rank: Frequent Contributor
timestamp: December 30, 2022, 10:52:59 pm
content: I wouldn't reheat the wax. When it first dripped onto the board it would have solidified quickly with a lot of dust in there, hopefully meaning that it currently has the weakest bond.Melting the wax again will ensure it really sticks, and gets into every little crevice.

author: MunsterAbu
author_rank: Newbie
timestamp: December 31, 2022, 12:00:56 am
content: Thanks for all the great helpful comments.Emboldened by this:Quote from: Kleinstein on December 30, 2022, 08:06:54 pmWithout heating the wax, I gently poked at it with a toothpick and a big chunk of wax came away very easily. I think that this must have been the case:Quote from: John B on December 30, 2022, 10:52:59 pmSo I continued and got most of it off (see photo). I think I will leave the remaining little bits. There is also some that dripped down onto another board underneath but I can't reach that without taking things apart, so I think I will leave that wax there.I tested the receiver and it seems to work fine. Fingers crossed!Do you think I'm OK now? Thanks!

author: TheDefpom
author_rank: Frequent Contributor
timestamp: January 01, 2023, 09:36:46 pm
content: I have seen wax intentionally used in transceiver VCO circuits to prevent air currents causing frequency drift and to physically prevent component movement, I really wouldn't worry about it too much, it likely won't cause any harm, unless it is prevent parts from cooling or blocking a heatsink etc.For wax removal if you really want to get it off, scrape off what you can (without damaging whatever is underneath), and then use a hot air station to SLOWLY melt it with the device turned upside down so it comes back out the way it went in to prevent further spread. you won't get it all out, but a gentle rub with a brush after its cooled back down will help get off what is left.