need help with aegis 152TA touch screen

HI

trying to reaper the Aegis 152TA 15" touch screen.

https://www.electro-tech-online.com/custompdfs/2012/01/Aegis2015.pdf


as I connected the 12v power supply wrong polarity, I suspects I damage it

the problem: not turning on.

things I tried:

opening the screen, I sow a bad capacitor (exploded), replace it with different capacitor from shop ( look diffident, but I have been told it's same):

old cap- (22 25a)
**broken link removed**

new cap (22mf 50v)
**broken link removed**

checking the screen after replacement - no change

I checked the power board- I could see that the 5V pin show 0v ( 12v OK):

**broken link removed**

testing the diode (disconnect 1 leg) show it is fine.
so I suspect the U13. ( is it a voltage regulator?)
need help with that

**broken link removed**

the part number is:1796-50a G3417A


thank you




**broken link removed**

Appears to be an Aimtron AT1796 - https://www.electro-tech-online.com/custompdfs/2012/01/at1796-50_488409.pdf

Bad news: Aimtron went out of business years ago. The design looks like an LT1074 from Linear Technologies, but sadly does not seem to be a drop-in replacement.

duffy said:

Appears to be an Aimtron AT1796 - https://www.electro-tech-online.com/custompdfs/2012/01/at1796-50_488409.pdf

Bad news: Aimtron went out of business years ago. The design looks like an LT1074 from Linear Technologies, but sadly does not seem to be a drop-in replacement.

Click to expand...

thank you duffy

is it possible to check this regulator on-board? if not, what is the easiest way to test it?

Got a scope? Fire it up and see if you get a square wave on pin 2. Make sure pin 5 (SHDN) is grounded (if it isn't already) when you give it the +12V, might be a control-line issue. Not sure what else you can do.

But keep in mind that all you REALLY need is a small +5V switching power supply module that works with a +12V input and puts out 3A...

...which is something you can buy for around $20. http://search.digikey.com/us/en/products/PT6302A/PT6302A-ND/278549

no scope... only multimeter .

As I'm taking the 12v source from the PC, can I take also 5v from it and connect it to the 5v on board?

it could help me see if more if problem are there.

if i do so, should I disconnect something else?

That's a good idea, the +5V from the computer supply should have an extra 3A to drive this and it is over-current protected. Like you say - there could be other problems.

I would disconnect that 1796 first, in case it is shorted internally.

connecting to +5V
the screen steel doesn't turning on ... must be something else .

is there any way to get this screen scheme?

tofutofu said:

is there any way to get this screen scheme?

Click to expand...

I don't know what you mean there. Did you give it both the 12V and 5V?
Unfortunately, if you hooked the 12V up backwards, it could have fried a lot of stuff in that monitor.

duffy said:

I don't know what you mean there. Did you give it both the 12V and 5V?
Unfortunately, if you hooked the 12V up backwards, it could have fried a lot of stuff in that monitor.

Click to expand...

hi
i gave both 12v and 5v. didn't help

you r right, connecting 12v opposite cloud make a lot of damage .
im not sure if the cap I replaced is fitting .

I want to check it out, but don't have the circle diagram.

would it help if I pass a pic of the circle?

tofutofu said:

I want to check it out, but don't have the circle diagram.

would it help if I pass a pic of the circle?

Click to expand...

No, it's ok, here's a circle diagram for reference -

duffy said:

No, it's ok, here's a circle diagram for reference -
View attachment 60694

Click to expand...

nice circle...



circle = electrical circuit