screen switches off after 5 sec :(

the_didge · 07-03-2007, 11:25 AM

Hi, i recently bought a (used) screen and it dosnt seem to work properly.

I have it connected to a 12v supply and the unit powers on, shows my pc screen then it switched the screen off and the whole unit freezes.

the model number(s) is

SP 716
PO 701
VMI 70A

can anyone help at all??

many thanks

muldrick · 07-03-2007, 12:21 PM

Probably a dumb reply, but make sure you don't have your screen setup to turn off in Control Panel> Power options.

the_didge · 07-04-2007, 03:24 AM

No, this is my work pc and all settings are fine, its deffinatly something from the unit.

if there isnt any input it does the same thing.

the_didge · 07-04-2007, 04:18 AM

A New Update

If i leave the unit unplugged from any sources, it comes up with DISCONNECTOR for approx 10 seconds then the screen goes white.

Also the board seems to be getting very very hot.

GiODi · 07-04-2007, 10:26 AM

Simple solution....cool it. Try pointing a fan directly at the circuit board. If it stays on then you know what you must do

the_didge · 07-04-2007, 11:04 AM

i seem to have located the source of the heat, but not too sure

thats where the heat SEEMS to be comming from.

dupa2 · 07-04-2007, 10:35 PM

actually these are power regulators, and typically they would be hot if you have significant current draw.
Since the screen starts at all (from cold), I think these regulators are just fine, but something takes too much energy so these warm up too much.

The most power consuming circuits in the screen is backlight, I'd check on that first.

Anyway, can you figure overall current draw for whole screen(with multimeter plugged in line with power)? By this you'll find out if the screen is within parameters or not.

I would suggest to measure voltage on output of these 2 regulators. Typical screen needs 2 voltages: 3.3V or 5V for logic, and 12V for backlight. Make sure these voltages are within range of +/- 0.25V

See if any other parts are getting hot. But not with your finger directly on chips/transistors, I still remember my burns on fingers from some processor

the_didge · 07-05-2007, 02:46 AM

thanks for the info, everything seems fine but once the screen cuts out the voltage on the regulator drops from 12 to 6v

i tried pointing a fan at the regulators and the screen works perfectly.

should i try to mount a fan inside the unit or wont this be a good option...

the_didge · 07-06-2007, 11:21 AM

can anyone help with this at all, will a fan work or will it just blow the board

thanks

GiODi · 07-06-2007, 11:33 AM

What i did with my monitor was get some memory heat sinks from Radio shack and attach them to wherever it got hot. Then i built a small, ghetto enclosure to have an exhaust fan (also from radio shack). It cost me a total of $16. If your soldering skills are up to par, you can tap into contacts on the board to get 12V. The fan i got was 21db... i can't hear it at all. They sell 9db fans on newegg made by SilenX for about $20 shipped. They may be a little overkill so I suggest trying the radio shack fan first. If you don't like if, you can return it.

dupa2 · 07-06-2007, 07:32 PM

I'd suggest replacing those regulators with different, stronger model, can you read off what each one is saying? I can refer to parts that you'd need to replace with, you can also solder the radiator to the body (already soldered to board), hopefully it'll help.
I don't recommend a fan, do you really want to hear the noise from fan?