Crest Ultrasonic cleaning of corrosion - Page 1
Forum section: electronics / general

author: dss4all
author_rank: Newbie
timestamp: September 15, 2014, 04:36:32 pm
content: So after searching the form and reading through 8 pages of topics and the reply's im more lost then ever.I have some boards that where manufactured in the 80-90's dual side. Most corrosion is from leaking capacitors and two from tsunami (Salt water,sand).What i have used in the past was 75/25 vinegar/distilled mix and cleaned just random cap's. Now with the new boards 99% of the caps have leaked and has got under ic,gates and other components.My prep work will be removing slide switches, crystal's, and all the caps.What would be the best solution i could mix up to clean them up and any pointers of heat and duration would be helpful to get me in the ball park. Cost is a major factor also so 26L of IPA is not an option.Recap of what i would like and what i have.#1 neutralize the elctro and acid gunk on the board.#2 remove 20 year old flux#3 neutralize cleaning agentsCrest CP2600 7Gal / 26L tankIn U.S.A. so some of the good stuff i cant find or afford to have smuggled in.Thank you

author: G7PSK
author_rank: Super Contributor
timestamp: September 15, 2014, 05:24:34 pm
content: Citric acid for cleaning alkali and baking soda for acids.

author: dss4all
author_rank: Newbie
timestamp: September 15, 2014, 07:56:47 pm
content: OK got it citric then baking soda to counter the citric

author: David Hess
author_rank: Super Contributor
timestamp: September 15, 2014, 08:59:54 pm
content: I would not worry so much about removing 20 year old rosin flux. Any aqueous solution will take care of the salts from your flood. The electrolytic capacitors I am familiar with are all acidic (boric acid?) so I would use a weak base like dilute ammonia to neutralize them.Given my druthers, I would start by power washing the boards which will get rid of the bulk of the contamination. Hard water is fine for this.Then I would use a solution of hot distilled water (reverse osmosis is fine) with a little bit of TSP or dish soap and enough ammonia to smell. An ultrasonic cleaner is pretty harsh so I would let the boards soak and only run it for a short period. A dishwasher might be better.Then I would rinse in more hot distilled water after power washing again.I like to dry the boards in an oven at low temperature overnight.

author: dss4all
author_rank: Newbie
timestamp: September 15, 2014, 10:14:01 pm
content: TSP I have on hand normal use is 1/20 so your saying little so maybe start with 1/40.Ammonia is common to find but most have some sent added like lemon any experience with them?Thank you all for the replys

author: David Hess
author_rank: Super Contributor
timestamp: September 15, 2014, 10:52:47 pm
content: Quote from: dss4all on September 15, 2014, 10:14:01 pmIt just needs enough TSP so the water wets completely. The TSP substitute they have now seems to work about as well as the real stuff for this.QuoteAll that I can say is that they worked and I did not have any problem with the scent or coloring but I was very careful to rinse well. The warm bake out will drive out any residual ammonia which is why I like it.An air compressor is handy for drying before baking as long as you do not blow oil or condensation onto the board. The high pressure air can get into the area between the parts and the board.

author: dss4all
author_rank: Newbie
timestamp: September 16, 2014, 05:35:05 am
content: Thank you all for chiming in.Picked up the lemon ammonia on the way to the lab and was ready to rock and shock the crap off some test boards.Popped open the "New" CP2600HT shipping box and it was not newThe packing job was mostly a brown box around the whole unit. Dents and a broken handAnd first start with a full tank of tap water nada no shake, turn on the heat and have bake but smoke alsoNice smell of burnt cap or somthing.I can peek in the bottom vents and see the transducers are still on the tank but cant see others. now i hold on shipping it back to the seller or idk what will happen.. Fing ebay