Concept2 Forum

Hi everyone -
I just decided to purchase a used model C off craigslist after years of using the C2 at the local gym.
The lady I bought this from was obviously not using it.

When I picked the c2 up, i noticed the batteries had a little corrosion in the batt. compartment.
She switched out the batteries for me. I noticed 2 of the modes would work and the 3rd was a blank screen.

I quickly came home and decided to clean the PM2 with alcohol as described on this site.
After putting it back together, I have no LCD display at all. I checked a few of the circuits near the batteries with a DVOM to see if they were broken... Couldnt find a break.

So, it might be toast. I am in San Diego... Anyone know of a place I can get this repaired or replaced? Even better - advice on repair? Thanks in advance.

Actually my cleaning process has now evolved and I use White Vinegar. Yes it's true, vinegar is very Alkaline and it attacks that acid leakage and nutralises it. The board is washed in water then dried with compressed air then cleaned with alcohol and compressed air.

If you removed the LCD from the board, make sure you didn't put it back in upside down.

There is typically always a track somewhere that has corroded through, it's just hard to find unless you have already repaired several PM2's. Also check the battery tabs have no rust on them, the rust is a great insulator.

It helps if you have a background in electronics or else try and find someone that repairs them in your part of the world, however if your in the USA a PM3 is so cheap I would just be going for a new monitor and you can also then use RowPro.

Good Luck.

Carl Watts wrote:Actually my cleaning process has now evolved and I use White Vinegar. Yes it's true, vinegar is very Alkaline and it attacks that acid leakage and nutralises it. The board is washed in water then dried with compressed air then cleaned with alcohol and compressed air.

Whoa! Whoa! Whoa! A little basic (no pun intended here) chemistry here, please. White vinegar is just plain dilute (about 4%) acetic acid - emphasis on the acid - the opposite of alkaline (aka basic). If it is effective at cleaning up power cell leakage, then it might well be that the leakage itself was alkaline, as from alkaline cells which are the most common non-rechargeable cells used nowadays. The old pre-alkaline cells, i.e. the zinc cells, used an acidic electrolyte, namely ammonium chloride and, of course, the old standard automobile Pb/PbO2 batteries have sulfuric acid in their cells.

Bob S.

Found the Vinegar thing while searching the net.

The battery deposit is typically white and or with a green tinge. The reaction with the vinegar is that it attacks the corossion and you get bubbles. 30 seconds with a toothbrush and the board cleans up. Rinse with plenty of water (The screen and elastopolymer strips should be removed before any cleaning ) and then IPA and compressed air. The whole battery area is then clearcoted with Electrolube CPL. I have recovered and repaired several PM2's like this where the corrosion looks so bad you think it would be a write off.

If it's not working you have nothing to loose anyway.

Carl Watts wrote: The battery deposit is typically white and or with a green tinge. The reaction with the vinegar is that it attacks the corossion and you get bubbles.

The bubbles suggest that the deposit is carbonate in nature and the green tinge would likely be from copper. I don't know what specific alkali is used in the alkaline cells. It is possible that it is a carbonate, but, in any case, alkalis in general tend to pick up carbon dioxide from the air and become carbonates. The use of a weak acid like vinegar is the ideal way to deal with carbonate deposits. Stronger acids would be more effective (faster), but would cause further corrosion themselves, so vinegar is the way to go. But it does have to be washed away right afterwards because it can eventually cause corrosion like any other acid.

Bob S.

edit: I just looked it up and the alkaline electrolyte is reported to be potassium hydroxide - pretty corrosive stuff - about the same as lye. Exposed to air it will very quickly pick up CO2 to become potassium carbonate and, eventually potassium bicarbonate, either of which will produce bubbles of released CO2 when treated with acids - strong or weak. They still use zinc/manganese dioxide as the power source, just as in the old "dry" cells that had an acidic electrolyte.

Cheers for that Bob, yes unfortunatly it looks like that "Green Tinge" is from the copper tracks on the PCB and hence in some instances the track is completley etched away and gone or the break can be so thin it is hard to see but a multimeter will pick it up as an open circuit easily.

I can't help you repair your PM2, but I recently replaced my PM2 with a PM3. Let me know if you have any interest.