Check all your test points and report back the voltages you find. Should be:
TP1 GND Console
TP2 +8VDC Console
TP3 +12VDC Console
TP4 15VDC Drive Voltage
TP5 5 VDC Controller Processor
TP6 Power supply bridge negative
TPN Line frequency monitor
TP8 AC input ground
Test Point (TP)
TP9 Power supply bridge positive

 

Check all your test points and report back the voltages you find. Should be:
TP1 GND Console
TP2 +8VDC Console
TP3 +12VDC Console
TP4 15VDC Drive Voltage
TP5 5 VDC Controller Processor
TP6 Power supply bridge negative
TPN Line frequency monitor
TP8 AC input ground
Test Point (TP)
TP9 Power supply bridge positive

I have tested the DC powered test points I get 8 VDC, 15VDC, 5VDC BUT only 11.6VDC on TP3. Also I used TP 1 as ground for TP 2 and TP3 however 4 and 5 shows no power until I used the middle pin on a voltage step down regulator 7805 as ground. Also I don't know how to test pins 1,5, 6, 8,and 9

 

You asked earlier about incoming voltage. Here is what you should have:
1 AC LINE
2 AC NEUTRAL
3 GND
P1 is a 3 pin connector to the main power control board
TP1 should be your ground test point so I believe we need to center around TP4&5

Also, your 5 pin connector for the bridge:
1 Bridge Negative
2 Capacity junction
3 DC High Voltage Bus
4 Bridge Positive
5 AC Input
P4 is a 5 pin jumper connector for voltage selection

Can you get a couple of good pics around TP4 and TP5? What IC's are in the area? I see something with a large heatsink?

Is there a burn mark around C23?

What is the part # of the IC between R72 and C52 above the transformer?

 

You asked earlier about incoming voltage. Here is what you should have:
1 AC LINE
2 AC NEUTRAL
3 GND
P1 is a 3 pin connector to the main power control board
TP1 should be your ground test point so I believe we need to center around TP4&5

Also, your 5 pin connector for the bridge:
1 Bridge Negative
2 Capacity junction
3 DC High Voltage Bus
4 Bridge Positive
5 AC Input
P4 is a 5 pin jumper connector for voltage selection

Can you get a couple of good pics around TP4 and TP5? What IC's are in the area? I see something with a large heatsink?

Is there a burn mark around C23?

What is the part # of the IC between R72 and C52 above the transformer?

Firstly the IC is a cny 17F-3 octocoupler. Here is a giant twist. Life fitness would NOT provide a schematic BUT they just sent me a new $700 circuit board. They said reverse engineer that one because they will not send schematic. That's great of them but I still want to figure this out. I tested both boards on all 9 test pins and they are identical. One thing I didn't mention I changed the low ohm r22 sensing resistor because it showed 0 resistance, with a .005 ohm sensing resistor. BUT the only difference I can see with the 2 boards is the new one has a rubber mat( red 1 inch by 2 inch) under the 4 IGBTSs and between the aluminum heat shield. That's where I shorted out the first time. I thought the bottom of the IGBTs were negative and hence could be grounded against the heat shield. There was no rubber mat on the first board. Could that be issue?

 

Depending on the transistor type, the metal case is often the collector terminal. This may be the case and you may have shorted them out. Does the new board solve the problem? If so, we can check voltages and work backwards. Have you checked the octocouplers?

 

Depending on the transistor type, the metal case is often the collector terminal. This may be the case and you may have shorted them out. Does the new board solve the problem? If so, we can check voltages and work backwards. Have you checked the octocouplers?

The IGBT IS A IXSH30n60c where the drain leg is also the case (drain us collector correct?) so having that metal touch directly to aluminum heat sink board WOULD cause short? That's why new board has insulating rubber pad under IGBTs correct? How to test the octocoupler said in circuit? With power or without? And the ic with th black stand up heat sink is a top234yn power integrator. I believe I got 190 volts out of one pin.

 

Yes and yes. To test an octocoupler, use one of these test methods:
http://preher-tech.com/documents/optoisolators
To do it in circuit is a little more difficult, however if there is more than one and they are the same, sometimes you can tell by using an ohmmeter and comparing readings. One side is just an LED (diode test), and the other is a collector-emitter circuit (ohmmeter test)
What voltages did you find on the other pins of the integrated switcher?
Did you get pics around TP4 & TP5? I believe we need to concentrate in this area.
Did replacing the board fix the problem?

 

Hi There,

If your Bridge rectifier shorted, the IGBT set of "2" had failed. IGBT devices have an issue of losing gate control when the device fails, this usually allows an open channel inside that IGBT to pass full current, unregulated and harsh. Now this board has a Pair of IGBT's and then a set of KICKBACK DOIDES mounted near them.

You will "NOT" have any voltage on the larger storage caps until the console "enables" that safety relay, the large black relay you had drawn out, that I saw.

Here is how we should go forward....on that board, the Life 92247, there are about a dozen SMT capacitors in the power supply section that do take a dump. Now reworking these caps is not as easy as one might think, so if you attempt it, have the right tools or you are guaranteed to pull traces, and that's a no--no.

You can email me directly for specific info on this board and testing it at the bench level before installing the MCB into the treadmill and trying it.

You should also check a couple of things....please check R22, .005-ohm current sense resistor for opens.
Then, check capacitor C22, 332 @ 1000v(3300pf) for any signs of burning under this part. For some reason, enzymes and moisture gets trapped under this part and allows "shorting" from a large V- land area, to a trace which rides at V+, which this voltage when all is energized and running smoothly, will be about ! 365vDC ! and plenty of potential to jump traces with a little help with conductive salts/enzymes. Not real sure why I have seen this so often there, but it is what it is.

You can reach me at jatinahATrocketmailDOTcom for more specifics on this motor control board.
;o)

 

4 month old thread!
Max.