Anyone ever repair their PM2 besides new display?

the old galoot · Post by **the old galoot** » October 10th, 2009, 2:30 pm

I no longer have the PM2 monitor. Thanks to everyone who replied. 25 Feb 10. -- the old galoot.

Original post:

"Went to row the other day and totally dead. Changed batteries, nothing. Fiddled with input plug, nothing.

I'm fairly handy (e.g., soldered broken connections in car stereo) and thought that perhaps it was not getting any input, although if the input was zero, the monitor should still activate and show zeros, right?

What is sent from the rower to the monitor? My guess is DC volts. I could not detect any when working the rower and putting a voltmeter on the plug.

I haven't called Concept yet and will but have time to post now and thought I would ask if anyone ever operated on their PM2, or took it to a local electronics repair place."

Tinus · Post by **Tinus** » October 11th, 2009, 5:30 am

The signal from the sensor is a very low voltage pulse. You should be able to detect/record it when you plug it into your stereo or computer soundblaster. The pulse is generated by magnets in the flywheel passing a sensor. I have not yet figured out what kind of sensor this is but currently my guess is that it is a simple electromagnet in which an electric field is induced when the magnets from the flywheel passes by.

the old galoot · Post by **the old galoot** » October 11th, 2009, 1:34 pm

Tinus wrote:The signal from the sensor is a very low voltage pulse. You should be able to detect/record it when you plug it into your stereo or computer soundblaster. The pulse is generated by magnets in the flywheel passing a sensor. I have not yet figured out what kind of sensor this is but currently my guess is that it is a simple electromagnet in which an electric field is induced when the magnets from the flywheel passes by.

That sounds like a "magneto", similar to the ignition system on a small gasoline engine. Makes sense. So it must be some kind of voltage... I know one can get a jolt from holding a spark plug wire of a lawn mower (do not try this at home) so maybe I can get a slight jolt if I hold the plug and my partner pulls the handle...

I'll call Concept2 tomorrow and see what they have to say. I would really like a schematic of the PM2.

the old galoot · Post by **the old galoot** » October 11th, 2009, 1:35 pm

Tinus wrote:The signal from the sensor is a very low voltage pulse. You should be able to detect/record it when you plug it into your stereo or computer soundblaster. The pulse is generated by magnets in the flywheel passing a sensor. I have not yet figured out what kind of sensor this is but currently my guess is that it is a simple electromagnet in which an electric field is induced when the magnets from the flywheel passes by.

Thanks. That sounds like a "magneto", similar to the ignition system on a small gasoline engine. Makes sense. So it must be some kind of voltage... I know one can get a jolt from holding a spark plug wire of a lawn mower (do not try this at home) so maybe I can get a slight jolt if I hold the plug and my partner pulls the handle... but that depends on the amperage and I'll bet that is pretty low considering the flimsy wire that comes from the flywheel to the PM2

I'll call Concept2 tomorrow and see what they have to say. I would really like a schematic of the PM2.

Gick · Post by **Gick** » November 7th, 2009, 6:20 am

You will get no effect holding the lead whilst the handle is being pulled. The operating voltage is very low, probably less than 10 volts. The spark plug voltage of a petrol engine is typically 35,000 volts, hence the shock!
A detectable low voltage can be assessed by either a digital volt meter or just to prove the case, I placed the lead on my tongue and a GENTLE pull on the handle provided a tingling sensation. However, this is not a practice that I would recommend others to adopt.
It would alsobe possible to feed a 12volt bulb and see it glimmer.
I would urge you not to take the monitor apart, as with solid state equipment it is very easy to cause irreparable damage. Those working on electronics will wear an earth bonding bracelet to get rid of static electricity that we all generate, and which is enough to damage chips etc., let alone a misplaced screwdriver!

the old galoot · Post by **the old galoot** » November 7th, 2009, 1:43 pm

Thanks for the tip on the voltage. I had the thing apart a couple times and it would work -- for a while, then stop.

I think it is the display, because Concept2, at one time, sold replacement display screens. We were unable to locate any NOS display screens and we have since upgraded to the PM3.

If anyone wants the old PM2 they can have it. Send me a message.

Carl Watts · Post by **Carl Watts** » January 11th, 2010, 7:13 pm

Yes I'm repairing both PM2's and PM3's. On the whole they are pretty reliable but there are 2 IC's in the power supply that go in the PM2. One turns the power on and off the other does a voltage conversion to get a -3Vdc supply. The PM3 is a much better monitor, especially if you row online with RowPro. The bottom half of the display shows the leading rower, you and the rower closest behind you in name and a distance format.

the old galoot · Post by **the old galoot** » January 17th, 2010, 5:02 pm

the old galoot wrote:Thanks for the tip on the voltage. I had the thing apart a couple times and it would work -- for a while, then stop.

I think it is the display, because Concept2, at one time, sold replacement display screens. We were unable to locate any NOS display screens and we have since upgraded to the PM3.

If anyone wants the old PM2 they can have it. Send me a message.

Sorry for not updating this sooner but I have given the old PM2 away and don't have anything to give away anymore. Good luck to all of you with broken PM2s.