kiloofblow
Posts: 3
Joined: Sat May 04, 2013 8:37 pm

Re: Modifying a 3.5" car display for USB power.

Sat May 04, 2013 8:56 pm

I purchased a 3.5" screen from Amazon that looked the same as the ones shown here and for the same price. When I opened the case, however, it was a different board than what has been shown on this thread so far. I do not see that XL1509 chip, but there are three similar looking 8 pin chips.

Here they are:
RC4558 - http://www.alldatasheet.com/datasheet-p ... C4558.html

ACT4060A - http://www.alldatasheet.com/datasheet-p ... 4060A.html

Pm25LD512 - http://www.chingistek.com/img/Product_F ... %20v04.pdf

None of these seem to have the same connections so it may not even be one of those I need to look for.

I can upload a picture soon, however I do not have access to a camera at the moment.

Is there anything else I should look for on the board as fa a 5v connection?

Let me know if you can help! Thanks!

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dasimpson
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Re: Modifying a 3.5" car display for USB power.

Sun May 05, 2013 6:30 pm

yes they should be a 5 volt capacitor you can connect to

kiloofblow
Posts: 3
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Re: Modifying a 3.5" car display for USB power.

Mon May 06, 2013 10:40 pm

kiloofblow wrote:I purchased a 3.5" screen from Amazon that looked the same as the ones shown here and for the same price. When I opened the case, however, it was a different board than what has been shown on this thread so far. I do not see that XL1509 chip, but there are three similar looking 8 pin chips.

Here they are:
RC4558 - http://www.alldatasheet.com/datasheet-p ... C4558.html

ACT4060A - http://www.alldatasheet.com/datasheet-p ... 4060A.html

Pm25LD512 - http://www.chingistek.com/img/Product_F ... %20v04.pdf

None of these seem to have the same connections so it may not even be one of those I need to look for.

I can upload a picture soon, however I do not have access to a camera at the moment.

Is there anything else I should look for on the board as fa a 5v connection?

Let me know if you can help! Thanks!
Image

This is the board. Has anyone seen this version yet?

kiloofblow
Posts: 3
Joined: Sat May 04, 2013 8:37 pm

Re: Modifying a 3.5" car display for USB power.

Wed May 08, 2013 7:43 pm

dasimpson wrote:yes they should be a 5 volt capacitor you can connect to
What would be the best way to go about finding the 5v connection?

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dasimpson
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Re: Modifying a 3.5" car display for USB power.

Wed May 08, 2013 10:40 pm

multi meter on ther terminals of each cap or the 2 white boxed areas on the left for a reading of 5 volts

cherry
Posts: 6
Joined: Fri Aug 10, 2012 12:09 pm

Re: Modifying a 3.5" car display for USB power.

Sat Jun 22, 2013 3:29 pm

marcialr wrote:Hi! I bought this screen and once opened found that it has a slightly different board.
Image
On one corner I recognized a similar circuit as the one is explained in this thread to be unsoldered and read XL1509



so i looked for the datasheet


so i could identify pin2 as the converted current output (5V desired) and soldered directly the red cable comming from the usb. Note the bad work done both pin 1 and 2 are soldered together bypassing the circuit. Also soldered the black cable to the other side pins, whithout taking care as they all are ground

Image

Everything is working fine! the resolution is not good to do much text coding as i think it will tire your eyes very quickly but for some quíck and dirty things should be fine. Haven't tried video!

P.S. the 12V input cable should not be used now (the red jack on the first photo)
e21c wrote:I bought very similar display and I modified it as presented below. I assumed that there is a circuit similar to this one attached to XL1509-5.0 datasheet. Additionally, I didn't cut off any path or remove any element so my display may be powered from 5 or 12 V sources.
Hi guys, thank a lot for your posts. I have the same Board as you, but I'm not really 100% sure where I should solder. What I'd like to do is to take off the original red (or rather orange in our case) power cable and resolder it somewhere else, so I can use a USB cable that has a connector that will fit the power cable on the other side.

Can I just solder the orange cable to the pin nearest to the larger capacitor (?!?) on the 10v/22uF capacitor like in e21c's pic? Or do I have to connect Pin 1 and Pin 2 (short) of the XL1509 converter and connect my power cable to Pin 2 ?

Sorry for asking such a simple question, but I'd really like to power the monitor over USB and don't want to blow it. Cheers!

Karethoth
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Joined: Fri Jun 28, 2013 6:15 pm

Re: Modifying a 3.5" car display for USB power.

Sat Jun 29, 2013 1:39 pm

Well, I just connected the red wire to the positive lead of one of the two 10V capacitors.
Image

And here is a slightly more detailed view:
Image
As the two capacitors are in parallel, it doesn't really matter if you connect the red wire to the A or B pin, but I chose to connect the wire to the A pin for personal reasons. And as my soldering skills are sub par, I added some hot glue just to make sure it really stays still and won't be making any excess connections to components near it.

whatever
Posts: 7
Joined: Thu Jul 04, 2013 5:57 pm

Re: Modifying a 3.5" car display for USB power.

Thu Jul 04, 2013 6:14 pm

I have the exact same screen as Karethoth and I did the exact same thing but all I get is a blank screen. The screen turns on but nothing from the pi is displayed

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dasimpson
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Re: Modifying a 3.5" car display for USB power.

Fri Jul 05, 2013 6:45 am

you need video input for it to display that or like me it needs more then 5 volt

whatever
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Re: Modifying a 3.5" car display for USB power.

Fri Jul 05, 2013 7:25 pm

dasimpson wrote:you need video input for it to display that or like me it needs more then 5 volt
What do you mean I need video input? I have a video composite cable connected from the monitor to the pi. I even increased the voltage to 7 and there was still no display when the power wire is connected to one of those caps

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dasimpson
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Re: Modifying a 3.5" car display for USB power.

Sat Jul 06, 2013 8:16 pm

you see the far left the white box try and see if one of them is 5 volt
I would supply 12 volt as normal to the normal sport for it and see what gives 5 volt you should then beable to add 5 volt there wire thickness might be a issue and not allowing enogth current

whatever
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Re: Modifying a 3.5" car display for USB power.

Mon Jul 08, 2013 11:45 pm

dasimpson wrote:you see the far left the white box try and see if one of them is 5 volt
I would supply 12 volt as normal to the normal sport for it and see what gives 5 volt you should then beable to add 5 volt there wire thickness might be a issue and not allowing enogth current
This is what I did.

Image

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dasimpson
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Re: Modifying a 3.5" car display for USB power.

Wed Jul 10, 2013 10:35 pm

I see in the post above yours he also added 3 extra wire from the resisters below the ic to the line of contacts maybe that's the difference also he connected to the other cap that could make a difference also

whatever
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Re: Modifying a 3.5" car display for USB power.

Fri Jul 12, 2013 9:10 pm

dasimpson wrote:I see in the post above yours he also added 3 extra wire from the resisters below the ic to the line of contacts maybe that's the difference also he connected to the other cap that could make a difference also
Tried that. it didn't work still.

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dasimpson
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Re: Modifying a 3.5" car display for USB power.

Sun Jul 14, 2013 2:17 pm

the only difference I see then are the 3 wires his has that yours dosent

selorami
Posts: 3
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Re: Modifying a 3.5" car display for USB power.

Thu Jul 18, 2013 10:54 am

kiloofblow wrote:
kiloofblow wrote:I
ACT4060A - http://www.alldatasheet.com/datasheet-p ... 4060A.html
Is there anything else I should look for on the board as fa a 5v connection?
Image
This is the board. Has anyone seen this version yet?
This might be late for your problem, but for anyone else with same board:
I got my display today and first thing I did was taking it apart. It had exactly same PCB design. Here's what I did to make it work with 5VDC:
Image

The ACT4060A is adjustable DC/DC converter with output adjusted to 5V (with external resistors). I removed the inductor between ACT4060A and output capacitors, just in case if ACT4060A doesn't like getting voltage to the output without input voltage. While I was at it, I also removed the IC itself and diode next to the inductor, but that isn't necessary... Did it to get some parts for future projects.

I haven't tested the power consumption, but I quess it's little less than before the modification (package stated max 2W).

Picture isn't perfect, but good enough for 20GBP portable display.

killerhippy
Posts: 5
Joined: Wed Jul 24, 2013 11:39 am

Re: Modifying a 3.5" car display for USB power.

Wed Jul 24, 2013 11:54 am

Refering to postings at page 4 I have the same board Kronalias has posted
a youtube video about Fri Feb 22, 2013 4:12 pm and dasimpson assumes
Fri Feb 22, 2013 4:45 pm that it is sufficient to shorten 12 and 5 Volt pins
of the voltage control chip (is this correct?).

I'd like to do that because it is the simplest method I think. All you have to
use is a small cable to solder to 2 contacts on a not so small chip. Though you
need to know exactly where to solder.

Has anybody the same board and measured which pins are the correct ones?
Has anybody verified that this really works?

killerhippy
Posts: 5
Joined: Wed Jul 24, 2013 11:39 am

Re: Modifying a 3.5" car display for USB power.

Wed Jul 31, 2013 11:45 am

In between I have bought a 12 V 1 Ampere switched power source and the display runs fine with the raspberry pi.

I took pictures of the voltage control chip:
Image
Image

It reads
XD1509
-5.0E1
31329

and it has a dot at the very left bottom edge near to the capacitors.

I tried to find this chip to get the datasheet but no succes.

I'd like to ask if one of you knows this chip and can tell about it?

Is it save to use my multitool to measure the volts? Is my assumption about the dot that this signs minus correct? - I am unshure because it is at the wrong side...

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dasimpson
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Re: Modifying a 3.5" car display for USB power.

Wed Jul 31, 2013 5:24 pm

the dot tends to mean pin 1 of the chip
from looking at the photo as it is in that pick the pins facing you should be 12v next pin 5v from what I remmeber

killerhippy
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Re: Modifying a 3.5" car display for USB power.

Thu Aug 01, 2013 12:30 am

My power source delivers 14.2 V

Taking the dot as base, I have the following measurements:

...to the cable connector
^
I
-12,21 | -12,21 | -12,21 | -12,21
PIN1 | -6.71 | -7.17 | -12.21
I

to the capacitors

If I get minus measurements, I think PIN1 is not PIN1, what do you think?

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dasimpson
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Re: Modifying a 3.5" car display for USB power.

Thu Aug 01, 2013 3:17 pm

I would put the ground pin of the meter on the ground power lead then use the psotive side of your meter to read the chip pins

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dasimpson
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Re: Modifying a 3.5" car display for USB power.

Thu Aug 01, 2013 3:20 pm

the far left cap is 12 volt the other 2 should be the 5 volt if you follow that rul the chip uor looking at near the 12v cap the pin facing you is 12 nect is the 5

killerhippy
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Re: Modifying a 3.5" car display for USB power.

Thu Aug 01, 2013 11:51 pm

Thanks for your answers, I will look up that later.
Karamell wrote:I did it similar without removing anything:

Image

The big advantage is, that you can do this without any advanced soldering skills. :)
...
One thing wonders me...

What do you think, what if I give usb power to ground and 5V to 2 of the 4 pins that do look so much as if they were prepared for usb connection? Has anybody tried that, yet?

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dasimpson
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Re: Modifying a 3.5" car display for USB power.

Sat Aug 03, 2013 8:25 pm

yeah 2 are power and 2 are data lines to the soc not usb data lines

killerhippy
Posts: 5
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Re: Modifying a 3.5" car display for USB power.

Sun Aug 04, 2013 12:39 am

Works!
P8040019.JPG
P8040019.JPG (61.2 KiB) Viewed 5719 times
At least with my display it is possible to power it by usb just with 2 wires without the need to modify anything else.

Great.

If I need to, I can still use 12 V with the other connection.

Thanks all!

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