MathiasRyan
Posts: 2
Joined: Sun Jul 02, 2017 10:08 pm

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

Mon Jul 03, 2017 3:17 pm

Lordasriell wrote:Hello,

i didn't have the same board as you, but i was able to make it work at 5.2v.
The Step-Down Converter ,wich is a JW5022 (datasheet here) output 5v on pin 3 (see datasheet), so by putting 5v directly on this pin it will work like a charm ( maybe i can take of the chip too ?)

http://imgur.com/3VDslSd
the board itself (i don't think i have seen it in the topic ?)


http://imgur.com/bIwEC5f
the JW5022 Synchronous Step-Down Converter (sorry i took the picture after the mod so we can't really see the name)

http://imgur.com/ds6Iu6b
The screen working with a Pi zero w, both on a gba sp battery. (850mha, maybe a little bit low :| )

i thought this might help someone ^^

I have the same screen as this. I found another link online that shows this chip removed. Have you tried it?
http://www.sudomod.com/wiki/index.php?t ... #Variant_9

Also can the set of three buttons be removed from the screen if only one AV source is being used? Should the board detect which AV line is in use?

lexgamer
Posts: 3
Joined: Wed Jul 12, 2017 3:22 pm

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

Wed Jul 12, 2017 3:40 pm

Hi,

I need your help :(

I try to run a screen with this type of card.
http://hpics.li/f5dce1b

It turns on, flashes, displays colors, sometimes I see the interface of Recalbox.

Can you help me to soluttion this problem how can I do to power it in 5v?

Thank you

BMS Doug
Posts: 3824
Joined: Thu Mar 27, 2014 2:42 pm
Location: London, UK

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

Thu Jul 13, 2017 7:19 am

lexgamer wrote:Hi,

I need your help :(

I try to run a screen with this type of card.
http://hpics.li/f5dce1b

It turns on, flashes, displays colors, sometimes I see the interface of Recalbox.

Can you help me to soluttion this problem how can I do to power it in 5v?

Thank you
We would need better pictures / data from the card.

We need to identify the voltage regulator used, discover it's output voltage and how to bypass it (if necessary.

There is one 8 pin chip and 2 6-pin chips, please post the chip identifiers from those.
Doug.
Building Management Systems Engineer.

lexgamer
Posts: 3
Joined: Wed Jul 12, 2017 3:22 pm

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

Thu Jul 13, 2017 6:43 pm

Hi Doug,

I hope its enough

http://hpics.li/b0bd100

Thanks

BMS Doug
Posts: 3824
Joined: Thu Mar 27, 2014 2:42 pm
Location: London, UK

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

Fri Jul 14, 2017 7:27 am

lexgamer wrote:Hi Doug,

I hope its enough

http://hpics.li/b0bd100

Thanks
Hi LexGamer

It looks like a 25Q40 (the 8 pin chip) is 4M-Bit flash memory, one to the 2 six pin chips must be the voltage regulator.
Doug.
Building Management Systems Engineer.

lexgamer
Posts: 3
Joined: Wed Jul 12, 2017 3:22 pm

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

Sat Jul 15, 2017 8:05 pm

How can I test what chip is right? Is this risky?

A ship is 02683


EDIT : It's ok that works !! the left ship is regulator voltage .

Thank you for your help :)

c_roemer
Posts: 1
Joined: Tue Aug 22, 2017 7:35 am

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

Tue Aug 22, 2017 7:42 am

lexgamer wrote:
Sat Jul 15, 2017 8:05 pm
How can I test what chip is right? Is this risky?

A ship is 02683


EDIT : It's ok that works !! the left ship is regulator voltage .

Thank you for your help :)
@lexgamer, can you tell what you did to make it work?
i have a little struggle with the board version, and i don't know if it is broken by now.

thanks in advance
Christopher

Hiroc80
Posts: 1
Joined: Thu Aug 24, 2017 9:27 am

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

Thu Aug 24, 2017 9:31 am

Hello guys. I bought the BW auto monitor from Amazon. I connected the monitor to my Rasberry Zero but it does not work. Does anyone know how I can modify it to 5V? Attach the monitor photo. Thank you :)
Attachments
IMG_20170822_090804 (Large).jpg
IMG_20170822_090804 (Large).jpg (209.25 KiB) Viewed 7377 times

Scionsamurai
Posts: 2
Joined: Wed Aug 30, 2017 8:06 pm

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

Wed Aug 30, 2017 8:35 pm

Hello all,
I have this board.
5" reverse monitor pcb https://imgur.com/gallery/4K83d
I'm having trouble getting it to run off of 5v. It's a 5" reverse monitor. The 8 leg(pin?) Chips are labeled "MK 25D40BTIG 1717" (located in the middle of the board) and "Toehcode TD1519A FB516462" (side of pcb: there is a scratch on the or in the first word and B516 of the last word. Used best guess to get those so they might be off)
Any assistance would be greatly appreciated and sorry if this board was already addressed and I missed it.

BMS Doug
Posts: 3824
Joined: Thu Mar 27, 2014 2:42 pm
Location: London, UK

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

Fri Sep 01, 2017 9:16 am

Scionsamurai wrote:
Wed Aug 30, 2017 8:35 pm
Hello all,
I have this board.
5" reverse monitor pcb https://imgur.com/gallery/4K83d
I'm having trouble getting it to run off of 5v. It's a 5" reverse monitor. The 8 leg(pin?) Chips are labeled "MK 25D40BTIG 1717" (located in the middle of the board) and "Toehcode TD1519A FB516462" (side of pcb: there is a scratch on the or in the first word and B516 of the last word. Used best guess to get those so they might be off)
Any assistance would be greatly appreciated and sorry if this board was already addressed and I missed it.
The TD1519A is the voltage regulator. Measure the output voltage from pin 3. and let us know what it is.
Image
Doug.
Building Management Systems Engineer.

BMS Doug
Posts: 3824
Joined: Thu Mar 27, 2014 2:42 pm
Location: London, UK

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

Fri Sep 01, 2017 9:18 am

Hiroc80 wrote:
Thu Aug 24, 2017 9:31 am
Hello guys. I bought the BW auto monitor from Amazon. I connected the monitor to my Rasberry Zero but it does not work. Does anyone know how I can modify it to 5V? Attach the monitor photo. Thank you :)
We'd need to know about the voltage regulator chip to help.
Doug.
Building Management Systems Engineer.

Scionsamurai
Posts: 2
Joined: Wed Aug 30, 2017 8:06 pm

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

Sat Sep 02, 2017 12:46 am

Thank you for the reply BMS Doug!
I'm not sure if i'm in need of a new(decent) multimeter. I wasn't getting any reading from 1,3,4,5,6, or 8. I was getting in between 3.7 and 4.8 on 2 and 7.

BMS Doug
Posts: 3824
Joined: Thu Mar 27, 2014 2:42 pm
Location: London, UK

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

Mon Sep 04, 2017 1:34 pm

Scionsamurai wrote:
Sat Sep 02, 2017 12:46 am
Thank you for the reply BMS Doug!
I'm not sure if i'm in need of a new(decent) multimeter. I wasn't getting any reading from 1,3,4,5,6, or 8. I was getting in between 3.7 and 4.8 on 2 and 7.
This was when you were feeding it from a 5V supply?

Please connect a 12V supply to the board for testing purposes and tell us the voltage output on pin 3.
Doug.
Building Management Systems Engineer.

cmiles74
Posts: 1
Joined: Mon Sep 11, 2017 6:48 pm

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

Mon Sep 11, 2017 10:19 pm

BMS Doug wrote:
Fri Sep 01, 2017 9:18 am
Hiroc80 wrote:
Thu Aug 24, 2017 9:31 am
Hello guys. I bought the BW auto monitor from Amazon. I connected the monitor to my Rasberry Zero but it does not work. Does anyone know how I can modify it to 5V? Attach the monitor photo. Thank you :)
We'd need to know about the voltage regulator chip to help.
I believe I have this same unit. I think the label on the part is: MK, 25040ATIO, 1645. I'm not a big electronics guy, but this looks like the right part.

https://photos.app.goo.gl/XIZ2kUxLp210WMSD2

robbaz
Posts: 4
Joined: Sat Sep 16, 2017 11:13 am

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

Sat Sep 16, 2017 2:05 pm

Hi guys, I got the same BW screen board and I tried to check the two 6-pinned chips looking for the voltage regulator as BMS Doug said. I searched online for their datasheets without success. One is labeled as O26B3 and the other as JWBV 795D. I think that the second one is the voltage regulator. I supplied the board with 12V and these are voltages on each pin.
bw_screen.jpg
bw_screen.jpg (222.98 KiB) Viewed 7025 times
Can you help me to understand how to power this screen with 5V?

BMS Doug
Posts: 3824
Joined: Thu Mar 27, 2014 2:42 pm
Location: London, UK

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

Mon Sep 18, 2017 8:27 am

I Agree that the JWBV 795D is the voltage regulator, I was also unable to locate a datasheet.

The voltage regulator will have a recognisable set of inputs and outputs, the first 4 are likely to be present on most voltage regulators:
Vin (Input Voltage)
Vout (Output Voltage)
En (Enable)
Gnd (Ground)

The remaining pins are more varied, possibly:
Fb (Feedback)
BS (Bootstrap)

These Voltage regulator datasheetsmight give an idea of what to expect although it doesn't entirely match.


Pin 1: 6.2V (Vout?)
Pin 2: Gnd (Gnd)
Pin 3: 0.8V
Pin 4: 9.7V
Pin 5: 12V (Vin)
Pin 6: 2.7V (FB?)
Last edited by BMS Doug on Mon Sep 18, 2017 8:30 am, edited 1 time in total.
Doug.
Building Management Systems Engineer.

BMS Doug
Posts: 3824
Joined: Thu Mar 27, 2014 2:42 pm
Location: London, UK

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

Mon Sep 18, 2017 8:29 am

I would suggest feeding the board with a reduced voltage and seeing how the voltages change, try 9V if you can.
Doug.
Building Management Systems Engineer.

robbaz
Posts: 4
Joined: Sat Sep 16, 2017 11:13 am

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

Wed Sep 20, 2017 6:16 pm

BMS Doug wrote:
Mon Sep 18, 2017 8:29 am
I would suggest feeding the board with a reduced voltage and seeing how the voltages change, try 9V if you can.
Hi BMS Doug, at the moment I don't have a 9V DC supply reliable at home so I tried with an higher voltage, 24.4V. I hope this will help anyway!

These are my measurements:

Pin1: 7.18V
Pin2: gnd
Pin3: 0.78V
Pin4: 20.2V
Pin5: 23.7V
Pin6: 2.98V

BMS Doug
Posts: 3824
Joined: Thu Mar 27, 2014 2:42 pm
Location: London, UK

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

Thu Sep 21, 2017 7:41 am

robbaz wrote:
Wed Sep 20, 2017 6:16 pm
BMS Doug wrote:
Mon Sep 18, 2017 8:29 am
I would suggest feeding the board with a reduced voltage and seeing how the voltages change, try 9V if you can.
Hi BMS Doug, at the moment I don't have a 9V DC supply reliable at home so I tried with an higher voltage, 24.4V. I hope this will help anyway!

These are my measurements:

Pin1: 7.18V
Pin2: gnd
Pin3: 0.78V
Pin4: 20.2V
Pin5: 23.7V
Pin6: 2.98V
Pin 1: 7.18 (was 6.2V) (Vout?)
Pin 2: Gnd (Gnd)
Pin 3: 0.78 (was 0.8V)
Pin 4: 20.2V (was 9.7V)
Pin 5: 23.7 (was 12V) (Vin)
Pin 6: 2.98 (was 2.7V) (FB?)

Not that there was any doubt but Pin 5 is confirmed to be Vin.

Pin 1: Vout?
Pin 2: Gnd
Pin 3:
Pin 4: Enable
Pin 5: Vin
Pin 6: FB?

I'm pretty sure that Pin 1 is the output and Pin 6 is the feedback, how can we prove it?

Its time to step up to destructive testing:
If we disconnect pins 1 and 6 from the circuit board but leave enough connected to the chip we should see one of them drop to 0v (the feedback pin) and the other increase to near the supply voltage (the Vout pin).
Doug.
Building Management Systems Engineer.

BMS Doug
Posts: 3824
Joined: Thu Mar 27, 2014 2:42 pm
Location: London, UK

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

Thu Sep 21, 2017 8:33 am

If Vout is 6.2 - 7V then there is no guarantee that a 5V supply will be enough to drive it.
Doug.
Building Management Systems Engineer.

robbaz
Posts: 4
Joined: Sat Sep 16, 2017 11:13 am

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

Thu Sep 21, 2017 5:08 pm

BMS Doug wrote:
Thu Sep 21, 2017 7:41 am

Pin 1: 7.18 (was 6.2V) (Vout?)
Pin 2: Gnd (Gnd)
Pin 3: 0.78 (was 0.8V)
Pin 4: 20.2V (was 9.7V)
Pin 5: 23.7 (was 12V) (Vin)
Pin 6: 2.98 (was 2.7V) (FB?)

Not that there was any doubt but Pin 5 is confirmed to be Vin.

Pin 1: Vout?
Pin 2: Gnd
Pin 3:
Pin 4: Enable
Pin 5: Vin
Pin 6: FB?

I'm pretty sure that Pin 1 is the output and Pin 6 is the feedback, how can we prove it?

Its time to step up to destructive testing:
If we disconnect pins 1 and 6 from the circuit board but leave enough connected to the chip we should see one of them drop to 0v (the feedback pin) and the other increase to near the supply voltage (the Vout pin).
Yay, destruction time! :D Have you any tip about how to disconnect only those pins on this tiny component (other than probably phisically remove them forever with a cutter)?

Searching on another forums I also found this thread where a user suggested to completely remove the chip and connect 5V directly to our pin6 (feedback?) but another user tried this mod and did not succeed (maybe because he said that already fried the screen before).
What do you think about?

BMS Doug
Posts: 3824
Joined: Thu Mar 27, 2014 2:42 pm
Location: London, UK

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

Fri Sep 22, 2017 7:31 am

robbaz wrote:
Thu Sep 21, 2017 5:08 pm

Yay, destruction time! :D Have you any tip about how to disconnect only those pins on this tiny component (other than probably phisically remove them forever with a cutter)?

Searching on another forums I also found this thread where a user suggested to completely remove the chip and connect 5V directly to our pin6 (feedback?) but another user tried this mod and did not succeed (maybe because he said that already fried the screen before).
What do you think about?
I read that thread but am unconvinced in light of your voltage readings. if pin 6 is showing 2.7V (one of the common output settings for a voltage regulator) then the output voltage from the chip pretty much has to be either:

2.7V (which you read from pin 6) - which would mean that 5v is twice the designed output voltage and very likely to destroy the board.
or:
~6V (which you read from pin 1) with a voltage divider circuit producing a Feedback value on Pin 6 (which I think is the more likely). In this case putting 5V on pin 1 would reduce the voltage regulators output to 0.

Industrially produced boards tend to use a high melting point lead free solder, If you wish to de-solder the pins and pull them away from the board I would dilute the solder holding them to the board with a low melting point solder (such as chip-quick) and then bend them clear. The price of Chip-quick doesn't make it very economical for single usage purchase, possibly using a normal lead alloy solder would serve the same purpose (although not quite as well).

This video is a good guide to de-soldering.
Doug.
Building Management Systems Engineer.

robbaz
Posts: 4
Joined: Sat Sep 16, 2017 11:13 am

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

Fri Sep 22, 2017 8:06 am

BMS Doug wrote:
Fri Sep 22, 2017 7:31 am
robbaz wrote:
Thu Sep 21, 2017 5:08 pm

Yay, destruction time! :D Have you any tip about how to disconnect only those pins on this tiny component (other than probably phisically remove them forever with a cutter)?

Searching on another forums I also found this thread where a user suggested to completely remove the chip and connect 5V directly to our pin6 (feedback?) but another user tried this mod and did not succeed (maybe because he said that already fried the screen before).
What do you think about?
I read that thread but am unconvinced in light of your voltage readings. if pin 6 is showing 2.7V (one of the common output settings for a voltage regulator) then the output voltage from the chip pretty much has to be either:

2.7V (which you read from pin 6) - which would mean that 5v is twice the designed output voltage and very likely to destroy the board.
or:
~6V (which you read from pin 1) with a voltage divider circuit producing a Feedback value on Pin 6 (which I think is the more likely). In this case putting 5V on pin 1 would reduce the voltage regulators output to 0.

Industrially produced boards tend to use a high melting point lead free solder, If you wish to de-solder the pins and pull them away from the board I would dilute the solder holding them to the board with a low melting point solder (such as chip-quick) and then bend them clear. The price of Chip-quick doesn't make it very economical for single usage purchase, possibly using a normal lead alloy solder would serve the same purpose (although not quite as well).

This video is a good guide to de-soldering.
Ok! I got the same impression reading that thread.
I'll try to desolder that chip! I was concerned about how to desolder just two of those six pins but I'll try and I'll let you know as soon as possible! Thank you ;)

tamrielx
Posts: 1
Joined: Wed Nov 01, 2017 9:01 pm

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

Wed Nov 01, 2017 9:08 pm

Images aren't displayed for me : [

MathiasRyan
Posts: 2
Joined: Sun Jul 02, 2017 10:08 pm

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

Mon Nov 06, 2017 8:51 pm

MathiasRyan wrote:
Mon Jul 03, 2017 3:17 pm
Lordasriell wrote:Hello,

i didn't have the same board as you, but i was able to make it work at 5.2v.
The Step-Down Converter ,wich is a JW5022 (datasheet here) output 5v on pin 3 (see datasheet), so by putting 5v directly on this pin it will work like a charm ( maybe i can take of the chip too ?)

http://imgur.com/3VDslSd
the board itself (i don't think i have seen it in the topic ?)


http://imgur.com/bIwEC5f
the JW5022 Synchronous Step-Down Converter (sorry i took the picture after the mod so we can't really see the name)

http://imgur.com/ds6Iu6b
The screen working with a Pi zero w, both on a gba sp battery. (850mha, maybe a little bit low :| )

i thought this might help someone ^^

I have the same screen as this. I found another link online that shows this chip removed. Have you tried it?
http://www.sudomod.com/wiki/index.php?t ... #Variant_9

Also can the set of three buttons be removed from the screen if only one AV source is being used? Should the board detect which AV line is in use?
Just to update on this. I only tried to get this screen working today. I soldered the 12 volt power line of the screen to the 5 volt pad underneath the USB power of my rpi zero. After an initial amount of flickering the image stabilized. The screen appears to work without any modification.

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