PM2: Dead Display Problem solved

[bartender]

After two year of not using the rower the display did not work any more. No digits no reaction.
I tested the pickup with a voltmeter (was ok) and wiggled the cable pulled the plug...

Opening the case I found out that the display lost contact to the edges of the two rubber bands it was laying on. This bands contain some conductive material that is used to connect the display to the boards electronic. Over the years the glue or whatever loosened and the contact got lost. When I pressed the display manually onto the band the contact was there again and it was working.

So I put three layers of tape stripes at the upper and lower edge of the display to press the display harder onto this bands when I put it back into the case.

Now it is working perfect again.

Maybe this will help someone who has got the same probs with his PM2.

[Carl Watts]

Personally I have serviced dozens of these and the contact between the Elasopolymer strip and the LCD has never been a cause of the problem.

When you remove the board the strip should be firmly stuck to the board, this is not glue it just sticks over time and should require pressure along each edge a bit at a time with a blunt object to free it. The strips and board contacts should be cleaned with IPA and reassebled. The keypad is not glued on either. You have a later model with the wider carbon strips so it should be pretty good.

A dead or fading display is usually the LT1044 / MAX1044 not producting the +/- 3V required for the LCD and this can be an intermittant or even temperature related fault.

Battery acid leakage is still the cause of over 90% of the faults, otherwise the PM2 is an incredibly reliable unit if you run Alkaline, Litium or better still Ni-MH rechargables in it that don't have a habit of leaking when discharged.

Good Luck.

[apaik]

Hey Carl, I know you are the man to contact for bringing the monitors back to life so here is my issue if you could help me.

I had the same problem as the guy in the previous post about the "rubber" strips being the problem. When I hold just the LCD screen and apply pressure to the rubber strips, the screen comes to life. Should I just clean the strips and the LCD with rubbing alcohol? I can see the display change when I toggle through the buttons but only if I hold it at just the right angle.

Any help would be appreciated! Thanks in advance.

[apaik]

Also, there was battery corrosion but I cleaned it up with white vinegar. The board is pretty clean but I have not put a voltmeter to it. I'm really not that savvy with electronics so bear with me. Haha.

[Carl Watts]

Yes nutrualise the corrosion with Vinegar, rinse well and dry with compressed air immediately.

Clean the strips with IPA and a cotton bud and the board contacts.

Typically its the +3Vdc and the -3Vdc that affects the contrast of the display and you have loss or partial loss of the -3Vdc.