DIYbanter - View Single Post - Power supply problem on touchscreen contoller

mike[_22_]

On 11/22/2012 4:12 AM, wrote:
I've checked on this and this is what I found.

The original power supply is proving 5V - 2A, +12V - 0.3A, -12V - 0.2A
While the replacement power supply 5V - 4A, +12V - 2A, -12V - 0.5A

Has the common ground of the +12V and +5V effect on the -12V in anyway?

What do you mean by proving?
Do you mean "reading the labels on the power supplies?"
With the system operating, what voltages did you measure?
If you got the right voltmeter readings, look with a scope
to see if it's really DC.
Power supplies have a minimum load requirement. Sometimes
that's supplied inside. Other times, you're required to provide
some minimum external load for everything to work out right.

However when a new switching power supply was used the touchscreen did
not work. Reverting back to the supply from the CRT works flawlessly.

Exactly what was the symptom of "did not work?"

Does this mean that you left the touch screen attached to the LCD and only
swapped out the power supply?

Depending on the mechanical configuration, noise from the LCD backlight
might
affect the touch screen. You can check this by distancing the touch
from the lcd.