Hannspree T280H not turning on

[cschappa]

1st Post here guys. I have a T280H that the cat knocked over. Everything else was fine before the fall, but now there is no display. There is a yellow LED that pulsates dim to bright.

I have taken out the power supply, R0800-0805-060.
I tried to test the pin outs 12v, see pic, which reads 0.00
I do have 5v.

Also, I noticed, the 2 metal heat sinks, checking the voltage between the 2 of them reads ~60v, but I am not sure if that is normal.

I have looked at another post, similar PS, but a little different.

Thanks in advance for any recommended suggestions.

Craig

[nomoresonys]

Re: Hannspree T280H not turning on

Maybe the screen is broken, were any cables loose, look the screen over carefully with a flashlight.

[cschappa]

Re: Hannspree T280H not turning on

I just checked the screen with a flashlight, it all looks the same, no cracks or bubbles. The cables all look to be intact.

[nomoresonys]

Re: Hannspree T280H not turning on

Is the input set correctly, might have bumped it.

[nomoresonys]

Re: Hannspree T280H not turning on

Are you testing it with everything plugged in or is that cable unhooked?

[cschappa]

Re: Hannspree T280H not turning on

Testing with PS disconnected from everything, except main power.

[cschappa]

Re: Hannspree T280H not turning on

Is the input set correctly, might have bumped it.

When TV is powered on, the yellow light would turn blue.

[nomoresonys]

Re: Hannspree T280H not turning on

Test it with everything hooked up as normal, see what you have on those same voltages you checked.

[nomoresonys]

Re: Hannspree T280H not turning on

Can try a simple reset, unplug tv for a few minutes then press and hold power button on tv for 30 seconds, then plug it in and try it.

[nomoresonys]

Re: Hannspree T280H not turning on

Go ahead and heat up those capacitors on your powerboard for a couple minutes with a hairdryer, then try it.

[nomoresonys]

Re: Hannspree T280H not turning on

If nothing broke and all connections are good, kinda thinking maybe a marginal capacitor gave up.

[nomoresonys]

Re: Hannspree T280H not turning on

Suppose it could have loosened a solder joint so check the joints on powerboard.

[cschappa]

Re: Hannspree T280H not turning on

So, everything is reconnected, I tried to heat the board with hair dryer, and measured leads with meter.

12v = 0
5v = 0
5vsb = 5.2

The large brown cap, 450v 120uF reads 169v and does not change when power button is pressed.

[lotas]

Re: Hannspree T280H not turning on

Most likely, your power supply is only in standby mode; in order for it to go into working mode, it needs to give a command - this must be done by the motherboard (3-5V) to turn on the “remote” pin.

[nomoresonys]

Re: Hannspree T280H not turning on

Ok, so try powerboard as stand alone, prolly easiest way is unhook cable from powerboard to mainboard on mainboard side, leave it off for test, trace wires back and jumper #1 remote pin and #7 5vSB pin, so you are jumping thru the UNPLUGGED connector. Then plug power cord in and see if you have those missing voltages and see if the backlights come on.

[lotas]

Re: Hannspree T280H not turning on

Ok, so try powerboard as stand alone, prolly easiest way is unhook cable from powerboard to mainboard on mainboard side, leave it off for test, trace wires back and jumper #1 remote pin and #7 5vSB pin, so you are jumping thru the UNPLUGGED connector. Then plug power cord in and see if you have those missing voltages and see if the backlights come on.

Just connect through a 1 kOhm resistor.

[nomoresonys]

Re: Hannspree T280H not turning on

Resistor is good practice, a safety precaution, not needed if there is no mistake in making connections.

[lotas]

Re: Hannspree T280H not turning on

Resistor is good practice, a safety precaution, not needed if there is no mistake in making connections.

It is always needed in such cases, firstly, it is not known what voltage is needed on the “remote” 3v or 5v, and secondly, it (the resistor) limits the voltage supply current.

[nomoresonys]

Re: Hannspree T280H not turning on

Actually it's not worth debating, so go for the resistor, some have had unreliable results because of using the wrong size resistor, using the right size is fine.

[cschappa]

Re: Hannspree T280H not turning on

I was able to jumper #1 & #7, I couldn't find a 1kohm resistor.

No backlight, also no 12v or 5v.