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How to repair flash and surface accumulated LC of Sartorius LCD

cxc621

New Member
Our two Sartorius LCD FKF 2SS03 for our lab's temperature controller have the following problem:
One of them always flash as attached Fig.1 and Fig.2 show; another one the area near cracked surface accumulates the black
liquid crystals as attached Fig.3 shows. Does any one know how to repair them?

Thanks Fig 1.LCD screen flash.jpgFig 2. LCD screen flash.jpgFig.3.Cracked LCD.jpg
 
Last edited:

Externet

Active Member
Cannnot be repaired, will take the replacement from manufacturer as it is not a generic type : needs the 'g' and perhaps other characters on it.
 

gophert

Well-Known Member
Most Helpful Member
Our two Sartorius LCD FKF 2SS03 for our lab's temperature controller have the following problem:
One of them always flash as attached Fig.1 and Fig.2 show; another one the area near cracked surface accumulates the black
liquid crystals as attached Fig.3 shows. Does any one know how to repair them?

Thanks View attachment 119802View attachment 119805View attachment 119809
The black-out version is a lost cause.

The flickering dim one MIGHT be rejuvenated by taking it apart - carefully.
As you remove the glass, there is a foam "zebra connector" that brings power to the circuit on the glass. The zebra connector has strips of conductive carbon embedded in the foam and non-conductive strips. That way, when the foam block is properly placed, the circuits on the glass are properly fed from the PCB. Take it apart, hope the glass is fairly clean, clean the circuit board with clean water and soft Q-Tips or cotton balls or wood tongue depressor sticks/toothpicks. Make sure you do not scrape so hard that you pry the copper from the circuitboard substrate. Gently wipe each side of the zebra connector with distilled water. Clean the glass display with distilled water (where the zebra connector touches the glass).

Let everything dry well (overnight) and then reassemble.

Good luck. When you open it up, there may be big patches of green copper corroded PCB oxidation. Try not to rub this off too much. The little bit of copper metal may be barely holding on to complete the circuit. Be delicate and remember that crud/corrosion with an electrical connection is better than perfection on cleanliness with broken connections.

If the black bezel is ruined, you can use your artistic ability to make a new one with PowerPoint and a nice printer. I just used paper and a black/White laser printer.

It is usually a spill of NaOH or other caustic powders or liquids that cause this in chemical labs. I've cleaned a few in my days in the lab. They usually work and I had no experience the first time I cleaned one.

The good news is that you don't need a Sartorius balance to be successful in the lab. Those used to cost $600 to several thousand dollars 25-years ago. Cheap, Chinese-made balances are now available for under $100 and some one-decimal balances can be bought for even less ($20) on Amazon or eBay.
 

gophert

Well-Known Member
Most Helpful Member
Thanks , Gophert

I will try as your instruction.
You need to assume you are starting with a lost item so you have nothing to lose. If it does work partially and you really need it, keep using it as-is. There is a risk that it will never work and parts are no longer available for these old balances.
 

cxc621

New Member
The black-out version is a lost cause.

The flickering dim one MIGHT be rejuvenated by taking it apart - carefully.
As you remove the glass, there is a foam "zebra connector" that brings power to the circuit on the glass. The zebra connector has strips of conductive carbon embedded in the foam and non-conductive strips. That way, when the foam block is properly placed, the circuits on the glass are properly fed from the PCB. Take it apart, hope the glass is fairly clean, clean the circuit board with clean water and soft Q-Tips or cotton balls or wood tongue depressor sticks/toothpicks. Make sure you do not scrape so hard that you pry the copper from the circuitboard substrate. Gently wipe each side of the zebra connector with distilled water. Clean the glass display with distilled water (where the zebra connector touches the glass).

Let everything dry well (overnight) and then reassemble.

Good luck. When you open it up, there may be big patches of green copper corroded PCB oxidation. Try not to rub this off too much. The little bit of copper metal may be barely holding on to complete the circuit. Be delicate and remember that crud/corrosion with an electrical connection is better than perfection on cleanliness with broken connections.

If the black bezel is ruined, you can use your artistic ability to make a new one with PowerPoint and a nice printer. I just used paper and a black/White laser printer.

It is usually a spill of NaOH or other caustic powders or liquids that cause this in chemical labs. I've cleaned a few in my days in the lab. They usually work and I had no experience the first time I cleaned one.

The good news is that you don't need a Sartorius balance to be successful in the lab. Those used to cost $600 to several thousand dollars 25-years ago. Cheap, Chinese-made balances are now available for under $100 and some one-decimal balances can be bought for even less ($20) on Amazon or eBay.
Thanks ,Gophert
It seems that two glasses sheet are glued together as attached figs show. Can I take apart it directly using small straight screw drive? What kind of glue I can use for assemble after cleaning?


LCD06.JPGLCD07.JPG
 

gophert

Well-Known Member
Most Helpful Member
No, do not take it apart. If it is sealed, the glass is not the problem. Look at the connector and the copper traces on the PCB going to the connector m
 

gophert

Well-Known Member
Most Helpful Member
This display looks pretty good or as good as it is going to get. Make sure the connector block makes firm connection to the connector block on the pcb. Make sure the pins on the pcb connector are clean and free of corrosion. Use a soft pencil eraser to polish up the copper or brass pieces.
 

cxc621

New Member
This display looks pretty good or as good as it is going to get. Make sure the connector block makes firm connection to the connector block on the pcb. Make sure the pins on the pcb connector are clean and free of corrosion. Use a soft pencil eraser to polish up the copper or brass pieces.
Hi, Gophert
I have done as your suggestion. Now when I power on the balance, the LCD screen shows in seconds then become dim and disappear. How can we explain it?Are there any other methods I can use to fix it?

Zheng
 

gophert

Well-Known Member
Most Helpful Member
Hi, Gophert
I have done as your suggestion. Now when I power on the balance, the LCD screen shows in seconds then become dim and disappear. How can we explain it?Are there any other methods I can use to fix it?

Zheng
Make sure it is dry - check all the pcb traces going to/from the pcb to make sure there is an electrical connection. Sometimes you have to add jumper wires across corroded copper traces to complete the circuit.

Good luck.
 

cxc621

New Member
Make sure it is dry - check all the pcb traces going to/from the pcb to make sure there is an electrical connection. Sometimes you have to add jumper wires across corroded copper traces to complete the circuit.

Good luck.
In the same balance, the black-out LCD shows data well except the black area that cannot be read. The LCD without crack still become dim after I clean it with pencil eraser. Perhaps I need clean the pin slot of the connector to PCB and use hair dry to dry all area as some youtube video show for fix the LCD for calculator?
 

cxc621

New Member
Make sure it is dry - check all the pcb traces going to/from the pcb to make sure there is an electrical connection. Sometimes you have to add jumper wires across corroded copper traces to complete the circuit.

Good luck.
I cleaned the cable and slots of connector to pcb using electrical contact clean liquid, pencil eraser, needle and hair dryer (As Fig.2-3). The black numbers of LCD showed when LCD was switched on and then became thin and disappeared. I tried to disconnected and reconnected the connectors to PCB in fig.1 when all board was powered on, and got the same results. I am not sure the slots of connector is cleaned enough or if I should change the cable. Is it possible the replace the cable with the one attached to the cracked LCD?fig 1.JPGfig.2.JPGfig.3.JPG
 

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