Concept2 Forum

I have a PM2 that out of nowhere stopped responding to rowing. It shows all zeroes on the screen and doesn't change when you start rowing. I've already replaced the pickup wire, but no luck. I also removed the flywheel cover and cleaned the contact in there pretty good. So, it looks like it might be a bad monitor now, for some reason.

Has anyone had experience with repairing their PM2 or is there somewhere that could do that? I don't really have the $160 to spend on a new monitor at the moment.

Or maybe someone out there has an old PM2 that still works after they upgraded to a PM3/PM4 and would be willing to let the old one go???

Thanks for any help you can provide.

Have you replaced batteries?
Have you tried a four finger reset?

See: http://www.c2forum.com/viewtopic.php?f=10&t=7964

It is pretty rare that the PM2 doesn't respond to the tach input, however I had my first one the other day that was "Low Sensitivity". Have not found out what it is as yet and just did a board swap to fix it. Would try the above reset and new batteries first. The PM2 is a good monitor and it shows you all the basics and is generally very relaible with only leaking batteries finally killing them but the PM3 or PM4 is now alot better.

Citroen wrote:Have you replaced batteries?
Have you tried a four finger reset?

See: http://www.c2forum.com/viewtopic.php?f=10&t=7964

Yes, I changed the batteries and I just attempted your suggested "4 finger reset" and still same result.

There's noone out there that can repair a PM2 ?? It seems to be a good monitor, just has a bad lead somewhere.

Any help with a repair service (I live in Houston) or a refurb or old PM2 to replace mine would be much appreciated....

Carl, I know bwaiser from another forum and I've offered to bring his PM2 back to NZ for you to have a look at if he can't find anyone closer. I'll be in the states next month and he can ship it to where I'll be.
Would that be possible?

I may be able to diagnose it myself if the fault is obvious, but it would be a good excuse to get in touch with you anyhow.

Yes I'm happy to look at any faulty Performance Monitors.

I have a pretty good sucess rate with the PM2 as long as it is just a component fault or the corrosion is not too bad. If the batteries leak real bad the board is toast. Will send you a PM with my contact details.

I wasn't sure if I should start a separate thread just for this since it's related, but my PM2 isn't functioning properly. The display powers up and passes the display test (hold down OK and press Display). The problem is that it is not registering any sensor readings.

I've tried plugging it into a working erg to see if the sensor was bad, but the display just shows all zeroes.

I'm an electrical engineer, so I'm comfortable replacing components. Has anyone else seen this problem?
Thanks!

mhj555 wrote: I've tried plugging it into a working erg to see if the sensor was bad, but the display just shows all zeroes.

Have you replaced batteries?
Have you tried a four finger reset?

See: http://www.c2forum.com/viewtopic.php?f=10&t=7964

Yup, batteries are new, and the display works fine. I just did the 4 finger reset and it did what is mentioned in the other thread. The display and all functions seem to work fine. It lets you program in a workout as usual. It's just that when you start rowing, nothing on the display changes (i.e. timer doesn't start, meters stay at 0).

It doesn't seem to be able respond to the sensor signal. I tested it on an erg with a known good sensor, but still no change in the display.

After doing some multimeter measurements, I think U10 (MAX859) on the circuit board may be bad. I'm reading about 2.6V out (after the diode). If I'm reading the feedback resistors correctly, they are 153kOhms (R26) and 100kOhms(R27). That should yield an output voltage of about 3.2V.
VFB should be 1.25 but it's only 1.017.

The MAX859 is a Step-Up converter, but the output is lower than the input (3V). Has anyone else had this problem? It's just under the battery, and I know the battery has leaked in the past. I'm guessing the battery fluid shorted the MAX859 causing it to be damaged.

The MAX859 maintains a constant output voltage of 3V over the life of the batteries which vary from between about 3.2V new to about 2V when flat.

The LT1044 provides a +/-3V supply for the LCD.

What you possibly have is no voltage to the tach Op Amp which is via a 1K resistor R25 right under the battery contacts.

Is your PM2 throwing any error codes ?

What usually happens is the corrosion eats through a track by the pads and via's that go through the board.

There is also a track UNDER the MAX859 that gets hard hit when the battery leakage goes under it by capillary action.

You can PM me for more technical repair info & tips.

I've checked continuity on all the traces around the MAX859, and it seems that the battery chemicals didn't eat all the way through them.

I'm certain that at the very least, the MAX859 is the culprit. There could be other problems, but this chip seems to be dead, as the output voltage is just 2 diode drops below the battery voltage. That makes sense, since there are 2 diodes in that path. If I can get my hands on one I'll switch it, but all the usual vendors around here seem to be out of them.

Yes it could be dead but it's rare to have it fail. battery leakage under it can also be conductive and stuff up the current draw and operation. I don't think I have had a MAX859 fail, although I have replaced a few for too high a standby current that kills the batteries early.

A PM2 working will draw from about 1.78mA to 2.8mA but in standby it should drop to 0.06mA to 0.07mA.

Use a multimeter on Ohms to check all the tracks in the battery area for continuity and on mA to see what it is doing when trying to power up and go into standby.

Put some vinegar on the board, it eats the corrosion, then rinse it off with hot water and use compressed air to dry it.