Not quite 7x4 but the principles the same.
As you can see if you strobe one line and detect a 'return' line high (or low) as the case may be, it identifies a particular switch closure.

Max.

 

Well, ended up scraping off "faraday's cage" shield off the top of membrane assembly to see better. Still was difficult to see traces, separated membrane layers and traced every single key. Now to wait for microswitches and prototyping board to arrive and off i go to make a keyboard...

 

Sooo, keyboard done and working fine. Behold the monster i have created:

Diagnostics didnt reveal anything new. But upon closer inspection i found that i'm missing R75 resistor. And i dont know original value of it. Anybody care to take a stab at a guess (informed preferably )? Cant seem to find any photos with particular detail i need...
P1 header is where top console connects to wax/lift and motor controllers. (ignore crappy solder job, i'm rubbish and cleanup is pending...)

Overall board detail:

Now that i have control of the console i can start diagnosing actual problem - where comms are bad...

#Edit# Also, notice how gray and matte all solder joints are. Currently it is my nightmare, how to deal with it ? Nothing sticks to it, flux or no flux. And even if i manage to flow it, all the crap floats and prevents fresh solder from sticking/flowing...

 

I'm happy to announce that the treadmill is functioning again.
It was all due to corroded trace and missing 100k ohm resistor, which prevented upper console communicating with lower electronics (motor controller and wax/lift board). All functions tested ok. Now to get a new belt on and off i go to watch telly while losing weight...

If anyone need any info on this tradmill i'm glad to help.

 

Hi baronpork,
I am fixing this same thread mill for a friend and found the transistor mounted to the heat sink, on the wax board has melted and I cannot read the value but it differs from the others on the board. You de-soldered all the components in that area. Would you be able to tell me the value of at least the transistor.

George

 

Is it U4 you're interested in ?

Hi baronpork,
I am fixing this same thread mill for a friend and found the transistor mounted to the heat sink, on the wax board has melted and I cannot read the value but it differs from the others on the board. You de-soldered all the components in that area. Would you be able to tell me the value of at least the transistor.

George

 

Hi Baronpork,
Thanks for coming back. I'm looking for the value of U4.

 

And I do appreciate its not simply a case of a quick glance at the transistor. The housings have to be stripped to gain access.

 

Hi George,
have you fixed the Wax/Lift board from this Life Fitness treadmill? The damaged part is the TOP224YN.

 

Hi Christian,
Unfortunately not. I put in the new part. Can't remember what we used but I think the original was unreadable. The display lit up but made no sense. It's sitting in my friends shed at the moment but I'll see if thats the part I fitted and if not then ill get it. Thanks for coming back. I dont normally use this email address. That's how I missed your post.

 

Here's the datasheet ....

 

Thanks Joe,
I couldn't think how I came up with the right component but remember now and it was nothing sophisticated. I got access to a working version and stripped it down and managed to get the numbers from it. It's very likely that's the exact component I have installed however the display has been effected. Im not sure where to go from here.

 

Hi,
could you please tell me what is the status of this treadmill now? Why do you think that the display is damaged? Are you able to put 9-12VDC on the display to check if it will start? What is the status of the wax/lift board? Are the LEDs on when you put power on it? Are you able to send a updated picture of this board?

Thank you.

 

The display lights up and led's on wax board. The message which appears on the display is erratic. Ill get the guy that owns it to send me a video or photo of the boot up and paste here.

 

Great. Thank you. If possible please ask also about a video from the MTC - there is a small LED display and it would be nice to see the sequence of 10-15 digits shown there.