Hi
I've just found this forum, I'm searching for info, as I have been given a PM3 monitor to repair.
The monitor shows nothing on the display and the unit appears to be dead. The batteries are good and have been replaced, no response when the USB is connected, reset pressed or any buttons pressed.
I've opened the unit up and it all looks OK (backup super cap has had it, though no corresion of PCB)
Does anyone have any advice or info on how to fault find the PM3 monitor? A schematic would be ideal.
Many Thanks
Paul
PM3 Dead
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Carl Watts
- Marathon Poster
- Posts: 4702
- Joined: January 8th, 2010, 4:35 pm
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Re: PM3 Dead
Hi Paul, the first thing you need is a 3V power supply with an ampmeter. When you connect the power the switching power supply should draw a sharp spike of current as it tries to power up and then settles to about 32mA.This is a good sign it is working and you can move on to the next possible problem.
One of the common problems with the older versions of PM3 that used the Motorola micro is that it lost the constrast control output for the LCD display. Look for any of the gold test points arround the LCD connector area on the underside of the board that have any signs of black on them at all. This can cause corrosion that has eaten through the track as it joins the test point that is litterally a hairline break that cannot be seen with the naked eye.
No corrosion and no obvious components faults, like a schotky diode cracked in half and the unit powering up ok means an LCD contrast problem. This is not repairable. The BGA micro is VERY hard to replace, 3 out ot 4 micros's I removed we not the problem anyway as the PCB had failed underneath them and the Motorola Dragonball micro used in the pre-2007 version is now long since obsoleted and you cannot buy new unused ones anywhere.
Unfortunaly there is no schemetic that is made public, it certainly would help when your faced with your first one to repair but as you gain experience with fixing them you don't need one, but it would still be nice to have it.
Keep the graphic LCD display as a spare as another common fault is that the displays get vertical or horizontal lines missing.
One of the common problems with the older versions of PM3 that used the Motorola micro is that it lost the constrast control output for the LCD display. Look for any of the gold test points arround the LCD connector area on the underside of the board that have any signs of black on them at all. This can cause corrosion that has eaten through the track as it joins the test point that is litterally a hairline break that cannot be seen with the naked eye.
No corrosion and no obvious components faults, like a schotky diode cracked in half and the unit powering up ok means an LCD contrast problem. This is not repairable. The BGA micro is VERY hard to replace, 3 out ot 4 micros's I removed we not the problem anyway as the PCB had failed underneath them and the Motorola Dragonball micro used in the pre-2007 version is now long since obsoleted and you cannot buy new unused ones anywhere.
Unfortunaly there is no schemetic that is made public, it certainly would help when your faced with your first one to repair but as you gain experience with fixing them you don't need one, but it would still be nice to have it.
Keep the graphic LCD display as a spare as another common fault is that the displays get vertical or horizontal lines missing.
Carl Watts.
Age:56 Weight: 108kg Height:183cm
Concept 2 Monitor Service Technician & indoor rower.
http://log.concept2.com/profile/863525/log
Age:56 Weight: 108kg Height:183cm
Concept 2 Monitor Service Technician & indoor rower.
http://log.concept2.com/profile/863525/log
Re: PM3 Dead
Hi Carl
Thanks for your advice.
This one had me stumped for a while, it looked like the unit was running, but there was no switched +3V3 supply and no supply for the LCD panel. Eventually traced the problem to one of the Dragonball data lines being stuck low, lifting the pin on the flash device suggested it was the Dragonball that was faulty, so I feared the worst. However when I looked very closedly (under a microscope) there was a very small bit of corresion on the side of the BGA package itself. There appears to be part of the device leadframe exposed on the sides of the BGA package and the corrosion though microscopic was sufficient to provide a short to ground. Removing the corrosion with a scalpel fixed it.
Thanks Again
Paul
Thanks for your advice.
This one had me stumped for a while, it looked like the unit was running, but there was no switched +3V3 supply and no supply for the LCD panel. Eventually traced the problem to one of the Dragonball data lines being stuck low, lifting the pin on the flash device suggested it was the Dragonball that was faulty, so I feared the worst. However when I looked very closedly (under a microscope) there was a very small bit of corresion on the side of the BGA package itself. There appears to be part of the device leadframe exposed on the sides of the BGA package and the corrosion though microscopic was sufficient to provide a short to ground. Removing the corrosion with a scalpel fixed it.
Thanks Again
Paul