LCD screen

[Susco]

I have that salt water chlorinator, which has an LCD screen of 7 x 3 cm.

 

The LCD works, but the polarizing film has gone black, so now I have to shine with a torch on it to read it.

 

I notice the LCD glass can be easily removed, so I assume it will be possible to replace it.

 

Only I don't know where to look for it. The chlorinator manufacturer sells complete PCB only, so that is a no go.

 

Any suggestions where to find such a part?

 

Edited August 24, 2020 by Susco

[jastheace]

i've had a search. the only thing i've come up with is this.

amorn in pattaya (i think there's other branches, bkk and cm, but i don't know where you are) bottom of tuk com near friendship. take the whole pcb (to save cracking the display) and ask them. If you have a picture or image of what is on the display, such as all bits 'lit' up on a display check, they may be able to help. if its a module bespoke to zodiac, then very small chance outside of the OEM.

good luck

[jastheace]

also sometimes if the display is very weak, and only readable at funny angles, there maybe a couple of capacitors gone. can't see then on the image you've posted, so maybe on the other side. again amorn have these, or used to anyway.

look like these perhaps....

more likely the 2nd image.

[jastheace]

got it. 

here's the link. this is farnell uk, so should be easy to source in TH as well

count the pixels and measure whole module rather than what's visible to confirm. take this info to amorn and they can order if not in stock.

https://uk.farnell.com/midas/mc122032b6w-bnmlw-v2/display-lcd-graphic-122x32-bstn/dp/2675686

you can take the lcd bit of the pcb supplied. and bob's your mothers brother.

 

 

[Susco]

5 minutes ago, jastheace said:

got it. 

here's the link. this is farnell uk, so should be easy to source in TH as well

count the pixels and measure whole module rather than what's visible to confirm. take this info to amorn and they can order if not in stock.

https://uk.farnell.com/midas/mc122032b6w-bnmlw-v2/display-lcd-graphic-122x32-bstn/dp/2675686

you can take the lcd bit of the pcb supplied. and bob's your mothers brother.

 

 

How do I count the pixels?

 

The one you post has PCB attached, I'm actually looking for the LCD only, as it is easily removed from the PCB.

 

The measurements I posted is the exact size of the LCD glass.

 

I very much doubt that Amorn has anything in stock, other than cookies and candy, as they are a shadow of what they were 5 years ago, but I assume I can place an order myself with Farnell

[jastheace]

9 minutes ago, Susco said:

How do I count the pixels?

 

 

my error. i tried counting the pixels in the image you posted, and noticed it's an 'alphanumeric' display. 16 x 4 characters. that put the previous link out the window.

we need one like this;

although this is a 20 x 4. you do not have to use the pcb it comes with. 

i would,as mentioned already, check the capacitors (are there any?) as i have changed many many many on displays like this. when they begin to fail, gets hard to read as all the dots get 'lit' up so hard to distinguish the characters. can i have a picture of the other side of the pcb? will follow thread....

[Susco]

35 minutes ago, jastheace said:

my error. i tried counting the pixels in the image you posted, and noticed it's an 'alphanumeric' display. 16 x 4 characters. that put the previous link out the window.

we need one like this;

although this is a 20 x 4. you do not have to use the pcb it comes with. 

i would,as mentioned already, check the capacitors (are there any?) as i have changed many many many on displays like this. when they begin to fail, gets hard to read as all the dots get 'lit' up so hard to distinguish the characters. can i have a picture of the other side of the pcb? will follow thread....

I will take it apart tomorrow or so, as it is installed in the pump house, and post a picture.

 

I'm sure it is not the capacitors, because it started with a black dot in the middle which always got bigger, so it must be the polarizing foil that deteriorated.

 

I have actually quite few devices that have that problem lately, however none of them get sunlight as they are all indoors, as I know that can be a reason.

 

Thanks for your help

[jastheace]

ok. i think you're on the right tracks then re polarizing. maybe no sun but temps high in the pumphouse?

then you need 16 x 4 (16 character per row, 4 rows. transflective. most are 5v so get that.

 heres an ebay example

https://www.ebay.co.uk/itm/1PCS-1604-LCD-Display-HD44780-4x16-chr-16x4-BLUE-STN-NEGATIVE-Backlight-NEW/253630902609?hash=item3b0d947151:g:-EYAAOSwc~5a~paU

except has a green back light, but thats just the led colour so don't worry. comes on a pcb. the back has 6 lugs to straighten, then the black surround will come off. the display is now loose so care it doesn't fall out! theres a conductive piece of rubber to remember to use on the edges. get it on the edges or the display won't work.

there maybe some identifying mark or code on your one to help.

you like a challenge? 555

 

[Metropolitian]

Actually.. starting with a dark spot in the middle and then moving to all the screen during time is a corroded backfoil.

I had it with the remote from the aircon.

That one was an easy fix not beautiful but it worked out fine enough for the missus, for the 20x4 display as yours it's better to replace the display.

 

It looks like the PCB uses an - Hitachi 44780 connection - display.

You can find these as 2004 LCD. (Important is that you need one without an I2C interface, of which some of the LCD's come with)

Example sources :  Shopee (abroad) 104b  Shopee (inside Thai, faster shipping) 159b

 

Confirm that it is the same kind of display, by looking at the rear side of the PCB, but I think it is. Even the holes for the white spacers is there.

 

[Metropolitian]

[Metropolitian]

2 hours ago, jastheace said:

also sometimes if the display is very weak, and only readable at funny angles, there maybe a couple of capacitors gone. can't see then on the image you've posted, so maybe on the other side.

If the text on the display is unreadable and only able to read in specific angles then the contrast setting is mismatch, this is not just a few capacitors on the back of the display but controlled trough the pins (pin 3 to be exactly pulling up or down at pin 1 and 2). So if that is the case , the contrast, then you had to look on the PCB where the display is soldered onto.

[Susco]

Here are some pictures and dimensions of the LCD

 

PCB size 85 x 55

 

Black frame internal 84 x 40 x 6

 

visible area  61.5 x 25

 

window on the chlorinator 58 x 23

 

 

 

[maxpower]

The LCD and its connecting zebra strips are interchangeable on most of the standard 1604 Chinese LCD displays.

 

Unless really unlucky the existing contrast setting (if not software adjustable) should be ok after replacing the LCD.

 

Alternate solution is to remove the complete LCD sub board and replace which requires some de-soldering skill and the correct tools.

[Susco]

17 minutes ago, maxpower said:

The LCD and its connecting zebra strips are interchangeable on most of the standard 1604 Chinese LCD displays.

 

Unless really unlucky the existing contrast setting (if not software adjustable) should be ok after replacing the LCD.

 

Alternate solution is to remove the complete LCD sub board and replace which requires some de-soldering skill and the correct tools.

Thanks for reminding about the zebra strips

 

Where I previously took the measurements from the black from of a spare chlorinator, I now disassembled the one in use and the measurements of the glass are  83.80 x 40.70 x 2.77

 

So the problem will be to find the exact size.

 

The PCB is mounted with 4 small screws, but I guess the soldering will that row of pins at the top

 

 

[Metropolitian]

2 hours ago, Susco said:

 

 

Now clear that it is an 1604 , 16 characters and 4 lines.

Shopee has that here.

A blue screen cost the half of the green one, here.

 

You can try to change the glass first, before going the exchange of the whole element.

 

Do you have a actual picture of the item working with the faulty screen? So we can see the real issue.

 

It is also possible that the contacts between glass and board was simply lost and a clean up of the zebra rubber and the copper pads and glass sometimes fixs things.

Had that in the past with a few calculators.

[Susco]

9 minutes ago, Metropolitian said:

 

Do you have a actual picture of the item working with the faulty screen? So we can see the real issue.

 

A picture would result in just a black screen.

 

I disassembled it to take the measurements, and the is clearly visible that the polarizing foil is detaching from the LCD

 

Edit to add : I do see the ones you post has 4 black dots on the back, while mine has 3. Does that make a difference?

Edited August 25, 2020 by Susco

[Metropolitian]

12 minutes ago, Susco said:

 

A picture would result in just a black screen.

 

I disassembled it to take the measurements, and the is clearly visible that the polarizing foil is detaching from the LCD

In most case that is just fine. In fact there are two of them, at the front and at the rear of the glass.

Normally they are transparent and they change to black when you rotate one of them 90' .

 

In the past I have rotated some of them to make the LCD 'black' , they were squared so easy to do, anything displaying in the screen shows 'whitish'  . Inverted in fact.

 

All what the glass do is energizing crystals that by rotating blocks out either horizontal/diagonal/vertical light waves. Without foil you won't see that happens, the foil will make it black if the lightwave are blocked both hor/vert. direction.

 

You can try to remove the deteriorated polarizing foil and replace it with another polarizing foil, which isn't easy to get but they are out there.

 

Test the foil with your computer screen, only one foil should be transparant and when you rotate it in front of your screen it will change to blueish black.

 

12 minutes ago, Susco said:

Edit to add : I do see the ones you post has 4 black dots on the back, while mine has 3. Does that make a difference?

That's a possibility. But great change that the schematic for signalling tothe glass between the boards is universal with the 1604 glasses.

 

For the pin-outs between the big and small PCB the pins are the same.

 

So changing the glass -can- work.

Changing the whole element -will- work.

 

 

 

 

[Susco]

2 minutes ago, Metropolitian said:

In most case that is just fine. In fact there are two of them, at the front and at the rear of the glass.

I only see 1 foil, at the front, and it is black and has some folds in it, so it's coming of the glass.

 

At the backside of the LCD is silver metal plate.

 

5 minutes ago, Metropolitian said:

You can try to remove the deteriorated polarizing foil and replace it with another polarizing foil, which isn't easy to get but they are out there.

Been there, got the t-shirt, with the spare unit.

 

The foil came of easily enough, but there is some very persistent glue on the glass, and I cracked it trying to remove the glue.

 

I have sent the pictures and the dimensions to the seller on Shopee, to ask if he has one that sure fits.

 

Will see if he answers.

 

Thanks for your help

[Metropolitian]

 

Currently i have the 2004 and 1602 as in the picture here.

 

I have seen the 2004 with 4 black dots and even with 6 black dots once.

They house a small integrated circuit under it and is a way of cheap mass producing and mostly found in displays like in your watches.

The 1604 can come with 3 black dots, like this one and yours, but 4 black dot's isn't a big difference just a difference in the PCB production and the un-housed IC's used.

 

No 1604 here but not for long I just added the one I found in my shopping cart

[stouricks]

Try Radiospares.co.th.

 

[Metropolitian]

That is no working link.

 

But perhaps you meant RoseSound groups, also known as RS Components.

 

They do have the 1604/164 display, although the picture is blurry and no shots from the back.

The specs are the same as other options given earlier.

[Metropolitian]

37 minutes ago, Susco said:

I have sent the pictures and the dimensions to the seller on Shopee, to ask if he has one that sure fits.

 

Will see if he answers.

One thing to keep in account is the voltage. They come in two flavors, 5v and 3.3v.

Many newer displays works fine on both voltage, and many online are sold as 5 volt.

 

Are you able to measure the voltage on the original board?

(between pin 1 and 2 or the last two 15,16 which is for the background light)

[Susco]

39 minutes ago, Metropolitian said:

One thing to keep in account is the voltage. They come in two flavors, 5v and 3.3v.

Many newer displays works fine on both voltage, and many online are sold as 5 volt.

 

Are you able to measure the voltage on the original board?

(between pin 1 and 2 or the last two 15,16 which is for the background light)

I will have to take it off again, but the cheaper of the 2 you posted shows it work on 3.3/5V

[Susco]

On 8/25/2020 at 1:13 PM, Metropolitian said:

Now clear that it is an 1604 , 16 characters and 4 lines.

Shopee has that here.

A blue screen cost the half of the green one, here.

I ordered the blue screen and it arrived today.

 

It says on the package 5V, and I'm still not sure if mine is 3.3 or 5V.

 

Gonna try it on the spare unit first, and will first try if replacing the glass only works.

 

Is there something that can go wrong by trying this, or is it just a matter of it works or it doesn't?

[Susco]

On 8/25/2020 at 1:13 PM, Metropolitian said:

A blue screen cost the half of the green one, here.

 

You can try to change the glass first, before going the exchange of the whole element.

Ordered and replaced the whole element.

 

Total cost 96 Baht.

 

Works perfect, in my opinion much more bright than original, but that can be just an impression as has been a while since I had seen anything on the screen.

 

Original replacement would have been 196 AU$ + shipping.

[egypte]

On 9/23/2020 at 11:45 AM, Susco said:

Ordered and replaced the whole element.

 

Total cost 96 Baht.

 

Works perfect, in my opinion much more bright than original, but that can be just an impression as has been a while since I had seen anything on the screen.

 

Original replacement would have been 196 AU$ + shipping.

 

Have the same probleme here,

 

How easy was it to change ?

Any Soldering involved ?