Power supply problem on touchscreen contoller

I have an old IRIS 4d/35 system with touchscreen capabilities and display is CRT type.

Recently we upgraded the system to run on LCD displays where we needed to provide the touchscreen controller with a separate power supply since the power for the controller was previously drawn from the CRT power supply.

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

The supplies required for the touchscreen controller are 12V, -12V and 5V. The CRT power supply had a common ground and so does the new switching power supply.

Any idea what could be the problem with the new power supply. Any advise would be very much appreciated.

 

[Gareth Magennis]

Perhaps the switching supply is not able to supply enough current via one or
more outputs, and is shutting down.

Many off the shelf supplies will deliver a hefty dose of 5v, much less in
the way of +12v, and often way less than the +12v figure for the -12v.


Gareth.



<vernondopaul@gmail.com> wrote in message
news:f680cb02-a7c1-40ce-88f5-9026978fdf01@googlegroups.com...

I have an old IRIS 4d/35 system with touchscreen capabilities and display
is CRT type.

Recently we upgraded the system to run on LCD displays where we needed to
provide the touchscreen controller with a separate power supply since the
power for the controller was previously drawn from the CRT power supply.

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

The supplies required for the touchscreen controller are 12V, -12V and 5V.
The CRT power supply had a common ground and so does the new switching
power supply.

Any idea what could be the problem with the new power supply. Any advise
would be very much appreciated.

 

[Gareth Magennis]

<vernondopaul@gmail.com> wrote in message
news:5e452ef0-a547-4f75-bc12-c8eae372a85c@googlegroups.com...

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?

Well the new power supply seems well capable, so either there is something
you have missed re: common grounds, or perhaps its the power up sequence
that might be wrong, and the various devices are not communicating/booting
together properly.

Dunno.



Gareth.

 

[mike]

On 11/22/2012 4:12 AM, vernondopaul@gmail.com 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.

 

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?

 

On Thursday, November 22, 2012 8:57:10 PM UTC+8, mike wrote:

On 11/22/2012 4:12 AM, vernondopaul@gmail.com 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.

What do you mean by proving? Sorry that was a spelling mistake. I meant providing.

Exactly what was the symptom of "did not work?"
The touchscreen did not respond to any touch inputs.

Does this mean that you left the touch screen attached to the LCD and only

swapped out the power supply?
Yes that's what I did.

Will check the output with a scope since the voltages are not far apart in comparison.

 

[N_Cook]

<vernondopaul@gmail.com> wrote in message
news:f680cb02-a7c1-40ce-88f5-9026978fdf01@googlegroups.com...

I have an old IRIS 4d/35 system with touchscreen capabilities and display
is CRT type.

Recently we upgraded the system to run on LCD displays where we needed to
provide the touchscreen controller with a separate power supply since the

power for the controller was previously drawn from the CRT power supply.

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

The supplies required for the touchscreen controller are 12V, -12V and
5V. The CRT power supply had a common ground and so does the new switching

power supply.

Any idea what could be the problem with the new power supply. Any advise
would be very much appreciated.

Does the touchscreen use a high "static" voltage (ultimately via the CRT
accelerating voltage) as part of its operation ?

 

On Thursday, November 22, 2012 6:36:32 PM UTC+8, vernon...@gmail.com wrote:

I have an old IRIS 4d/35 system with touchscreen capabilities and display is CRT type.



Recently we upgraded the system to run on LCD displays where we needed to provide the touchscreen controller with a separate power supply since the power for the controller was previously drawn from the CRT power supply.



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



The supplies required for the touchscreen controller are 12V, -12V and 5V. The CRT power supply had a common ground and so does the new switching power supply.



Any idea what could be the problem with the new power supply. Any advise would be very much appreciated.

When we upgraded from CRT to LCD the touchscreen was upgraded at the same time. I suspect the problem is with the power supply as reverting back to the original solves the problem.

 

[Cydrome Leader]

vernondopaul@gmail.com wrote:

I have an old IRIS 4d/35 system with touchscreen capabilities and display is CRT type.

somehow your post was stuck somewhere for about 15 years.

not sure about the touch screen problem though.

I have to ask- what is this thing still being used for??

 

[Jon Elson]

vernondopaul@gmail.com wrote:

I have an old IRIS 4d/35 system with touchscreen capabilities and display
is CRT type.

Recently we upgraded the system to run on LCD displays where we needed to
provide the touchscreen controller with a separate power supply since the
power for the controller was previously drawn from the CRT power supply.

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

Are you saying the touchscreen placed on the LCD panel works

fine when powered by the old power supply? If so, then that eliminates
the LCD drive signals as a concern for fouling up the signals on the
touch panel. CRTs have some noise on the front, but the shadow mask
generally isolates the front from a lot of noise. LCDs are REALLY
noisy beasts, with 50V pulses on a zillion "wires" on the front
of the panel.

But, assuming it really is only the power supply that is different, then
it is either the power-up sequence or noise. Possibly the new supply
voltages come up in a different sequence than the old one, or there
is noise on one or more of the voltages.

Jon

 

On Tuesday, November 27, 2012 6:39:50 AM UTC+8, Jon Elson wrote:

vernondopaul@gmail.com wrote:



I have an old IRIS 4d/35 system with touchscreen capabilities and display

is CRT type.



Recently we upgraded the system to run on LCD displays where we needed to

provide the touchscreen controller with a separate power supply since the

power for the controller was previously drawn from the CRT power supply.



However when a new switching power supply was used the touchscreen did

not work. Reverting back to the supply from the CRT works flawlessly.



Are you saying the touchscreen placed on the LCD panel works

fine when powered by the old power supply? If so, then that eliminates

the LCD drive signals as a concern for fouling up the signals on the

touch panel. CRTs have some noise on the front, but the shadow mask

generally isolates the front from a lot of noise. LCDs are REALLY

noisy beasts, with 50V pulses on a zillion "wires" on the front

of the panel.



But, assuming it really is only the power supply that is different, then

it is either the power-up sequence or noise. Possibly the new supply

voltages come up in a different sequence than the old one, or there

is noise on one or more of the voltages.



Jon

Will check on the sequence on power up, thanks Jon.

 

On Thursday, November 22, 2012 6:36:32 PM UTC+8, vernon...@gmail.com wrote:

I have an old IRIS 4d/35 system with touchscreen capabilities and display is CRT type.



Recently we upgraded the system to run on LCD displays where we needed to provide the touchscreen controller with a separate power supply since the power for the controller was previously drawn from the CRT power supply.



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



The supplies required for the touchscreen controller are 12V, -12V and 5V. The CRT power supply had a common ground and so does the new switching power supply.



Any idea what could be the problem with the new power supply. Any advise would be very much appreciated.

 

On Monday, November 26, 2012 3:57:47 AM UTC+8, Cydrome Leader wrote:

vernondopaul@gmail.com wrote:

I have an old IRIS 4d/35 system with touchscreen capabilities and display is CRT type.



somehow your post was stuck somewhere for about 15 years.



not sure about the touch screen problem though.



I have to ask- what is this thing still being used for??

Cydrome,

the 4d/35 is being used on a flight simulator. The company is planning to replace the iris system but I would still have to maintain the old simulator.