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Help troubleshoot Sharp 12" display on running treadmill

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tartex

New Member
Hi!

The display on our "treadmill running machine" has stopped displaying graphics and I need some help to troubleshoot before eventually buying an new display.

I would really like to find out whether its the display thats mailfunctioning or any circuit before the display connector. (the programs seems to be functioning, but nothing shows in the display).

I have found the following connection table for the "Sharp LM32P07" display:

PIN No. FUNCTION PIN No. FUNCTION
1 Vo - -16.5V
2 VEE - -24V
3 D3 9 P0
4 D2 10 P1
5 D1 11 P2
6 D0 12 P3
7 NC - -
8 VSS 3 GND
9 VDD 5 VCC
10 CP2 35 SHFCLK
11 CP1 38 LP
12 S 36 FLM

Does anyone know if its possible to use any standard interfaces on an laptop or workstation computer to test the graphics functions on the display? Or any other ideas?

Regards
Marcus (sweden)
 

HiTech

Well-Known Member
Does this display use the standard 15-pin VGA connector? If so try connecting it to a working monitor.
 

tartex

New Member
A new display costs about 300-400$ and I need to know if its the display or the circuit-board that is mailfunctioning.

The display uses 12 -pin...
 

birdman0_o

Active Member
"Stopped displaying graphics" is pretty vague. It could be anything, loose connection, dead LCD, dead processor. It's not under warranty?

And jeeez , and new TV is cheaper than that :p!
 

meatpie

Member
Try this first to test the backlight.
Darken room and hold a small torch close to the screen.
If you can see the graphics then the screen is ok but the backlight has failed.
Come back with results.

Meaty
 

tartex

New Member
Its a "Quinton" treadmill.
MeatPie: I tried your tip but I saw nothing. The fact is that i tried with and without connecting the backlight connectors. But no graphics.
As a matter of fact, the backlight went out as I troubleshooted as suggested. I connected it while the treadmill was on, and the backlight worked at first, but the second time it just went dead.

Any other ideas?
 

meatpie

Member
It can be very difficult to see what's on the screen without the backlight. You'll have to move the torch around. Hold it right against the screen.

You'll need to get some light into that screen somehow to see if it actually has graphics on it. Try removing one of the backlights from the screen and shine a torch into where you removed it from. In computer monitor size lcd's they slide out.

You could make a tester as follows.
Buy a ccfl light like this one : 2x White 15cm Car CCFL Neon Exterior/Interior Light - eBay Other Lights, Indicators, Lights, Indicators, Car Parts, Accessories, Cars, Bikes, Boats. (end time 14-Dec-09 22:46:22 AEDST)

Cut half way along the wires that go to the 2 lamps. Make sure you tape them as pairs. Now you have 2 testers.
Disconnect the LM32P07 backlight connector.
Strip the ends from the tester inverter and poke them into the display backlight connector.
Connect an external 12volt supply to the tester.
Be aware that backlights are very high voltage so keep away when you switch it on.

Meatpie
 
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