UTComp or Display failure after 12V to ACC +5V OUT(B6)

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Sergej
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Joined: Sun Apr 25, 2021 10:13 pm

UTComp or Display failure after 12V to ACC +5V OUT(B6)

Postby Sergej » Mon Apr 26, 2021 1:04 pm

Hello,
after installing and connecting the "Reveltronics" Oil pressure sensor (10 BAR) to the UTComp Pro using the 5V supply from B6, the Pressure seemed to be slightly low at Idle to me. First of all I wanted to figure out if the Voltage supply of the sensor is sufficient. Measured the Voltage output At B6 and it was about 4,8 V which might bi to low for the sensor?! As next step I was going to connect 12V for the sensor supply to see any difference in sensor reading.
This is where the problem occurred. Giving the sensor 12V I forgot to unpin the supply from B6, feeding in 12v to the 5V bar of the UTComp Pro. I heard the buzzer indicating me that I messed it up.
Now the display doesn't work properly like there is no backlight. The UTComp unit though is working, USB connection and all the sensor readings also the 5V supply works still with +4,8V at B6.

Any Idea what I might have broken the display or the control unit? The display lights up again if I repeat my failure connecting 12V to B6.

Cheers

ArT
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Re: UTComp or Display failure after 12V to ACC +5V OUT(B6)

Postby ArT » Tue Apr 27, 2021 3:54 pm

4,8V for oil pressure sensor is fine (4.5V and above is fine).

Connecting +12V to +5V output may damage module and display. When you connected +12V to +5V rail, you had also +12V on all +5V outputs on UTCOMP. From +5V outputs are powered sensors, buzzer, keyboard and display.

Which display do you have, LCD or OLED? UTCOMP-3 or UTCOMP-PRO?

Sergej
Posts: 3
Joined: Sun Apr 25, 2021 10:13 pm

Re: UTComp or Display failure after 12V to ACC +5V OUT(B6)

Postby Sergej » Wed Apr 28, 2021 8:21 am

It's a UTCOMP-PRO with the 3,2" white OLED. It better be the unit, is an easy one to replace. The display though is built and glued in, which will be a pain to replace...
As mentioned before, the unit seems to work fine with all sensor readings and supplies, buttons and buzzer also work.
On the display I see a start-up picture but very dark when I turn the key on. The clearly see that I uploaded a start-up picture with reversed contrast (white background).

ArT
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Re: UTComp or Display failure after 12V to ACC +5V OUT(B6)

Postby ArT » Thu Apr 29, 2021 9:45 am

Seems like module is fine and I worry that oled panel may be damaged or DC/DC converter on display board. The easiest way to find out is to connect second display to module. You can send to us module (without disassembling oled screen until we will know what is damaged) and we can check it with other display.

Sergej
Posts: 3
Joined: Sun Apr 25, 2021 10:13 pm

Re: UTComp or Display failure after 12V to ACC +5V OUT(B6)

Postby Sergej » Mon May 03, 2021 12:56 pm

Hello Artur, I pulled the display out, to have a look on it. To me it seems like the Resistor (R17) got hot and fell off or so (see picture). Doesn't look right like this. I will see if I can fix this otherwise I will send the unit in for a check and order a new display.

Any Idea what the resistance value might be?
Attachments
IMG_2804[1].JPG
IMG_2804[1].JPG (1.75 MiB) Viewed 76 times

ArT
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Re: UTComp or Display failure after 12V to ACC +5V OUT(B6)

Postby ArT » Tue May 04, 2021 8:04 am

It looks fine. R17 is not placed from factory. This small cap between pads is also mod from factory.
You can send unit and display for checking, we will see


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