DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

[DSPEngineer]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

This morning I changed the left LCD display, and the PSU is working now:
https://photos.app.goo.gl/pTw3qxBHe1GG5Hfh7

I really hope that it will keep working for several years. I almost never used it but still the LCD display stopped working. I am worried that the right display also will fail soon but at least I know what to do now.

[DSPEngineer]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

I ordered this:
https://www.elextra.dk/details/H1416...8aAkB0EALw_wcB

[DSPEngineer]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

Thanks Ali101.

I am thinking about ordering:
"EDS805 LCD Display Module 4 Bit 8 Digit TN Segment LCD 50.8x30.48x2.8mm 45.72x16.51mm Metal Pin"

https://www.aliexpress.com/item/3277...archweb201603_

I seems to have the right size and the right number of pins. Do you agree?

/Kim

[Ali101]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

from Aliexpress
https://www.aliexpress.com/item/7263...rchweb201560_4

but as i know soldering stuff and have right equipment so i order only LCD Glass but it will be better for you to buy hole penal if you don't have right equipment and knowledge. just search on above website 8 segment Digital LCD Module and you will get bunch of results.

[DSPEngineer]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

I have the df-1730sbc-3A where the right display is still working but the left display shows LO BAT -1.8:88, just like yours. If you get your PSU with the new LCDs, I would really appreciate if you could tell me where you bought the LCDs.

[Ali101]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

still waiting for LCD delivered from China, shall post back here once received new LCD,

Thanks Sam.

[sam_sam_sam]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

@R_J no difference with clean sockets and board, all same, all segments on,

@eccerror i had replaced new IC 7106 but it not fixed issue, hence it is LCD fault, buying new LCD and shall replace,
Thanks.

Let us know what happens when you install the new LCD displays if it works or not

Thanks

[Ali101]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

@R_J no difference with clean sockets and board, all same, all segments on,

@eccerror i had replaced new IC 7106 but it not fixed issue, hence it is LCD fault, buying new LCD and shall replace,
Thanks.

[eccerr0r]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

The 7106's say ImBAD so they must have failed. *runs*

If you catch the segments on with the power off and capacitors discharged, try taking a piece of wire and shorting the "BP" signal to each of the segment pins. It should instantly turn the segment off. If not, the LCD is clearly bad.

(as an aside) Hmm... I have an extra ICL7116 lying around, need to put it in something. Hate having this as a spare when I'm still using magnetic movement meters to monitor voltage... have a few 2-digit LCD modules at my disposal, just need to etch a board. just need to...

*sigh*

[Ali101]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

@R_J no i not did, let me try this before placing LCD order online,
Thanks for suggestion, appreciated,

[R_J]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

quote from post#9

i did clean all boards of power supply with IPA using brush but nothing seems working,

Did you remove the ic's from the modules and clean the sockets and board, it does'nt take much to cause the ic's and display not to function.

[sam_sam_sam]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

To swap between LED/LCD with the same board, the 7106 and 7107 are very much alike ... but are different!!! You need to board edit to swap between the two.

7106 pin 21 is an output used for the backplane and must not be grounded as it can sink or source current.
7107 pin 21 is used for system ground reference and is the current sink pin for the LEDs

7106 pin 26 is battery V- and must not reference pin 21.
7107 pin 26 is negative supply, and is referenced to pin 21.

Other than rerouting the segments and the LED common anode/LCD backplane wiring, these pins on the IC also need to be reconfigured.

This is why I made the comment that it would be better to buy a double sided board and mount the LED meter module to so you do not have modified the case where the meter display is

One note I have not sat down and look both versions to see all of what needs to be done to use the board that is in the power supply display board

[Ali101]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

@sam @eccerr0r thanks alot for professional suggestions and kind help, appreciated, shall follow them on same,
Shall return with feedback once done,
Thanks.

[eccerr0r]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

To swap between LED/LCD with the same board, the 7106 and 7107 are very much alike ... but are different!!! You need to board edit to swap between the two.

7106 pin 21 is an output used for the backplane and must not be grounded as it can sink or source current.
7107 pin 21 is used for system ground reference and is the current sink pin for the LEDs

7106 pin 26 is battery V- and must not reference pin 21.
7107 pin 26 is negative supply, and is referenced to pin 21.

Other than rerouting the segments and the LED common anode/LCD backplane wiring, these pins on the IC also need to be reconfigured.

[sam_sam_sam]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

The pinouts of the ICL7106 and ICL7107 are so much alike but the pinouts of the LCD modules and LED 7-segment modules are quite different.

Yeah probably best to just get meter modules, but if you're planning to simply replace the LCD, might well just cut off the old ones and clean up. The problem is that the way pins are connected to the glass LCD substrate will easily break when heated or even touched.

The display module is different you are correct

But the pins on the meter ic chip are the same

segments keep on even disconnect all connections of Power supply from display board & just give 9V external to display board,
ONE LCD is around USD $2 but i need to buy them from China Online (Aliexpress) & it will take huge time to arrive,
so can't be quick results,
have any suggestion to try before remove LCDs?

If there is no circuit under the display then you could basically put the LED display on top of the main meter board and just hook up power inputs and the meter input

Because you will probably need the original board to be able to mount the meter display to the case unless you buy a double sided blank board that is big enough to mount the meter module


But if go the route of replacing the LCD display you need to very careful installating the new one that the display is mounted correctly so it can be seen correctly you have basically one chance at if you do not use a ic chip header and then put the display pins in the header

If was doing this —> this is the route I would take using a header and then the LCD display

But I would not recommend just replace the LCD module because the couple of links you posted it appear that these display are crap

I would replace LCD display module but I have done them before I have a Desoldering Gun station that I repair quite a few times and have had to remove the LCD display to fix or replace the back light module

It can be a real pain in the a** to do this if you do have a Desoldiering Gun station and even if you have one it still can be a pain in the a** to do and get it right

[sam_sam_sam]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

The pinouts of the ICL7106 and ICL7107 are so much alike but the pinouts of the LCD modules and LED 7-segment modules are quite different.

Yeah probably best to just get meter modules, but if you're planning to simply replace the LCD, might well just cut off the old ones and clean up. The problem is that the way pins are connected to the glass LCD substrate will easily break when heated or even touched.

The display module is different you are correct

But the pins on the meter ic chip are the same

If there is no circuit under the display then you could basically put the LED display on top of the main meter board and just hook up power inputs and the meter input

Because you will probably need the original board to be able to mount the meter display to the case unless you buy a double sided blank board that is big enough to mount the meter module


But if go the route of replacing the LCD display you need to very careful installating the new one that the display is mounted correctly so it can be seen correctly you have basically one chance at if you do not use a ic chip header and then put the display pins in the header

If was doing this —> this is the route I would take

[eccerr0r]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

So the segments are all on when the PSU is off? That sounds like bad LCD.

The pinouts of the ICL7106 and ICL7107 are so much alike but the pinouts of the LCD modules and LED 7-segment modules are quite different.

Yeah probably best to just get meter modules, but if you're planning to simply replace the LCD, might well just cut off the old ones and clean up. The problem is that the way pins are connected to the glass LCD substrate will easily break when heated or even touched.

[sam_sam_sam]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

I would not recommend doing this because the quality of these display have gone down hill

When I played with them many years ago this was not a problem with these display

I would recommend going to the LED version of this meter module you find them fairly easily on eBay or Alibaba.com or Banggood.com or some where like this

I saw them for about $12.00 each in kit format and even less than if you look hard enough

The ICL 7106 and ICL 7107 have the same exact pin out the only difference is that the ICL 7107 has extra circuit for the LED segments

Now this one does not have the extra circuit on this one

https://www.ebay.com/itm/ICL7107-Dig...wAAOSwqS1dXjtv

You will need to use the red defuser with this display

[Ali101]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

segments keep on even disconnect all connections of Power supply from display board & just give 9V external to display board,
ONE LCD is around USD $2 but i need to buy them from China Online (Aliexpress) & it will take huge time to arrive,
so can't be quick results,
have any suggestion to try before remove LCDs?

[eccerr0r]

Re: DC Power Supply (DF1730SB-5A) Programmable LCD Reading Problem

weird, and the segments turn off when power isn't connected?

LCD failure is like very low on my suspects unless all the segments stay on without bias...

Now getting one of those through hole LCD displays...and how much would one cost, or rather... two?