f the plating is gone, you'll either have to replate or replace the contact s for reliable contact"
If the plating is damaged, the water will cause rust, but that's the least of your problems. Water will quickly and cleanly dissolve the crud, but if the plating is gone, then you can try sanding the base metal clean and app ly a blob of dielectric grease between the battery and the contact to seal the connection if you don't want to spend any more effort on it.
You're doing better at repairing corrosion damage than me. The problem is that the corrosive fluid tend to narrow the trace width of traces that are still making a connection. Add a little current through the trace, and you have a fuse. Also, the electrolyte acts like, well... and electrolyte. Two parallel traces, separated by a hygroscopic PCB, with a DC voltage across the gap, is going to slowly erode one trace, while building up the other. The net result is that it works for a while, and then craps out again.
I just had both of these effects happen while trying to fix a Rayovac LED head lamp. I think it was this model: It's quite a decent head lamp, at a good price, and is rate to be water resistant up to IPX4 (splashing water). However, there's no protection against the alkaline batteries leaking all over the PCB. I gave up after it came back the 4th time with essentially the same problem.
The damaged PCB is in my "to be recycled" bin. I can take a photo and post it if anyone wants to see the mess.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
I beg to differ. I have had NiCd and NiMH cells leak. The difference is that unlike alkaline, they don't leak in the package: I've found from dealing with commercial walkie-talkie batteries, that if I leave the packs totally discharged for more than a few weeks, the batteries will leak. The good news is that this rarely happens.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Depends on what you're dealing with. $20 electronics deserve no effort unle ss it's for the satisfaction. But like John, I've repaired extensive PC da mage where the board is unavailable or stupidly expensive. Back in the pro jection TV heyday, I used to do tons of Mitsubishis that suffered coolant l eaks onto double side plated through hole circuits both for myself and othe r dealers that wouldn't attempt it. I bought a stereo microscope to help id entify missing/damaged traces and damaged plated through holes. The TVs we re several thousand dollars to replace and the boards were several hundred dollars when they were available. Even so, changing the main boards on Mit sus meant a total realignment afterwards.
You do what you have to do.
KenO schrieb:
[...]Own experience (with alkaline battery corrosion) a few hours ago :-( ... I have to admit though that my experience is just with the battery contacts and not with PCB corrosion.
HTH
Reinhard
NiCd also white
NT
I've had several NiCds & NiMHs leak, but way less often and far less quantity than primary cells. Usually there's no significant damage to the battery holder.
NT
While reading this thread, several questions keep coming up.
First, why cant the battery makers design batteries that cant leak? I suppose cost is the main reason, but it would seem that there could be a coating of something like silicone rubber or some sort of plastic that could contain any leakage inside the battery's container.
Secondly, I often read on instructions "Do not mix battery types". Meaning dont use both carbon-zinc and alkaline batteries together. I have often questioned the reasoning for that. ??? I am aware that Carbon/zinc batteries produce 1.5V and Alkaline produce 1.2V, so that could be an issue with some electronics, but would probably not matter in a flashlight.
I do sort of wonder if mixing battery types would cause corrosion and leakage between the two dissimilar batteries, the same way connecting copper plumbing pipes to a galv steel pipe does. I've seen the dielectric corrosion occur mostly at the joint between the different pipe materials, which is the first place for a leak to occur. (They do make dielectric unions to isolate the metals),
Then the thought also occurs, what wouyld happen if both types of batteries began to leak at the same time. Would one leaking chemical neutralize the other, or would the two chemicals react and cause a reaction, which may produce dangerous fumes, or create heat, which could result in a fire? (I never studied chemistry, so I really dont know).
Lastly, Has anyone ever come up with a "Battery Pan", meaning an enclosure around the battery compartment that would keep leakage confined to ONLY the battery compartment? If not, why not? In an ideal world, the battery compartment for all electronics would be removable and replacable, with a universal battery holder (for each type of battery). This would also be leak proof. I'm sure this could be done, but once again, we're back to cost. And we live in a disposible world, so I dont forsee this ever happening.
I've had 100's of NiCad/NiCd batteries leak on our pinball game boards since the 1970s. I stored these leakers for many years in a couple of milk crates (didn't want to simply toss in garbage) until the recycling provided by our city (Vancouver, BC) gave us a new home for them.
John :-#)#
--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
I have also had some NiCd batteries leak. But that was after years of non-use. In fact I had some brand new ones (still in their package), that got misplaced and years later I found them and they were corroded inside the package. The corrtosion was confined to the package so nothing aside from the batteries was damaged, and I just tossed them in the trash.
QUESTION: What are those coin cells? (like the ones used in computers for the system clock). Has anyone ever seen them leak? I ask because I have several old computers that have been sitting around un-used for years, and I never removed them cells.
If you trash them, do they emit some sort of dangerous substance? I would prefer to recycle stuff like that, but I've never seen any place that takes small batteries like that. In my area. (Yes, they do recycle car batteries though).
Just curious. It sounds like you repair pinball machines. Aside from playing them when I was a kid, I know little about them. But I did once see one taken apart, and it appeared to be little more than a complicated bunch of relays and lights. And they operated from a wall outlet. I kind of think there was a power transformer inside, so I assume those relays and lights were low voltage. (probably 6 or 12V).
So, why are there batteries inside of them?
Well yeah, the early electromechanical pins used relays, switches, and solenoids. Scoring was by indexed reels. Starting in the late 70s, they started using electronics for sound and light controls plus digital scoring and play field animation.
The CR2032 coin cells are solid lithium and not rechargeable. (The MR2032 are rechargeable.
The CR2032 type cell does not contain any liquid electrolyte. There's nothing inside that might leak. The lithium is the clear stuff, which turned white when exposed to air. The black stuff carbon.
The cells are probably dead by now. I have a pile of 10-20 year old motherboards in the closet. The coin cells haven't leaked. The previous generation of batteries leaked all over the PCB.
-- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
Batteries are used to keep book-keeping information - number of games played, number of coins, replay levels, game adjustable features, etc. The most common chip used at first was the 5101 256x4 CMOS RAM, needed roughly 2VDC to maintain and usually a 3.6VDC Ni-Cad battery was installed to keep that device charged.
I didn't toss these batteries as I didn't want to pollute the garbage with them and kept them under my bench in a milk crate (had two crates filled over 20 years - they didn't leak enough to make any sort of mess or odor) and in the last few years recycling got to the point where they would take old batteries at no charge so we could finally safely dispose of them - I assumed safely, but not so sure now that I hear about all the recycling done in 3rd world countries...
John :-#(#
--
(Please post followups or tech inquiries to the USENET newsgroup)
John's Jukes Ltd.
MOVED to #7 - 3979 Marine Way, Burnaby, BC, Canada V5J 5E3
(604)872-5757 (Pinballs, Jukes, Video Games)
www.flippers.com
"Old pinballers never die, they just flip out."
Those must be newer pinball games. That open one I saw was probably
1950s era. I suppose they now have more computer circuits. Since you mentioned CMOS RAM, I see that is true. Now I learned something new :)
Yea, I know what you mean about the 3rd world recycling. Once again, the government is showing their stupidity. In my area, Goodwill stores can no longer sell computers or computer parts. I run older computers with PS2 mice and keyboards. I also prefer the old ball mice. My mouse died and I went to Goodwill to buy a new *used* mouse. I was told they are not allowed to sell any computer stuff anymore. It all must go to the state's computer recycling program. I said "but you should still be able to sell a mouse or keyboard". I was told they have no way to test them. (As if it's difficult to plug them into an old computer and see if they work. (Plus half the other electrical stuff they sell is broken anyhow).
It would seem to me that the best way to recycle things like that is to sell then to people who can reuse them, but when it comes to the govt. nothing they do makes much sense.
(I found a seller on ebay who was selling the old PS2 ball mice NOS for $5.50. I bought one and it was identical to my old one that died, so I bought a couple more. That's the kind of mouse I like, and I can use them on a newer computer too, with a PS2 to USB adaptor (which I also have).
tabb,
"Simple really. Alkaline batteries leave what looks like white fuzzy crystals. Some times with bluish green tint."
Blue and bluish green is what I have.
Have made 2 jpegs of the contacts and since have not received any tips how to attach in this forum Googled and found "HOW TO SHARE FILES WITH GOOGLE GROUPS by James T. Cains"
Somehow attach a file does not show in my Opera Browser or doesn't this forum allow attachments?
This is neither a forum nor google groups. This is Usenet news. Google groups is jut a web based method of reading it.
If you want to post pictures, get a DropBox account, upload them and post the link here.
-- "I am a river to my people." Jeff-1.0 WA6FWi http:foxsmercantile.com
or any other picture hosting site This is news:sci.electronics.repair.
NT
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