Hp 50g vertical display problem

[Randall]

My 50g has developed between 1 and 3 vertical lines in the display. When present the lines run the entire length of the display and appear at the same location (so far).

Light pressure on the display or twist on the calculator (in the right place) will make the lines go away. The shade of the line(s) is white. And remains white whether that part of the display is blank or should be showing something. It seems the problem is caused by a bad connection to the display.

I replaced the batteries even though the low battery indication was not on. No change in symptoms.

Any suggestions?

Thanks Randy

[cyrille de brébisson]

Hello,

You have 2 bad contacts between the PCB and the display.

The contact is done using a heat glued/sealed plastic flexible connector.

Most likely, this has been damaged (or the connection has weakened).

It IS possible, if you are super/very careful to fix such things, but it means opening the calculator, possibly also prying the LCD off and then re-heat glueing the connector strip, which is not an easy feat.

Usually, to do so, you place on the strip some non glue non melt plastic isolator (like anti static tape), and use the soldering iron at low temp to tranfert some heat on the connector and glue it...

I have done it once or twice, but it is hard.

Cyrille

[Randall]

Thank you Cyrille. I suspected a loosening and/or weakening connection.

Several years ago I had help and repaired a 39g display connection.

The 50g display repair is more than my capabilities.

I do have a prime but still use the 50g a lot. Guess I need to speed up the transition.

Thanks again. Randy

[Tugdual]

50g to Prime is not a transition it is a downgrade.
There is nothing that compares with the 50g.

[Alejandro Paz(Germany)]

Anecdote:
That problem used to plague the 48SX at the beginning of the 90s. I got one at the time with 1 missing line, and later it developed into 3 missing lines . The elastomer between the display and the PCB was/is defective, it is a sandwich of rubber and some conductive but flexible compound.

I used to apply some failure locating spray to the edge of the display, and because both compounds have different coefficients of thermal expansion you can see if the problem is there, the lines become visible.
***

Looking at the photos http://s1189.photobucket.com/user/_rs1n_...sort=3&o=8

It looks like they were for the conductive foil ( ), well apply so pressure between the foil and the PCB and see if the lines reappear, then, some glue may help.

[Randall]

(03-23-2016 06:52 PM)Tugdual Wrote:  50g to Prime is not a transition it is a downgrade.
There is nothing that compares with the 50g.

I experienced a lot of problems updating my prime operating system. So much so tha I left a note on the hp website. To my surprise, I received a call from a real person. I took the opportunity to add my prime product update requests: Rpl enhancements, DDAYS functions, and key label color improvements. When I finally got the prime updated dday functions were included.

My 49g+ was a good machine until the keys started failing. Eventually the 50g came along and provided a good platform.

I hope hp listens to users and modifies the prime accordingly.

[Randall]

(03-24-2016 11:11 AM)Alejandro Paz(Germany) Wrote:  Anecdote:
That problem used to plague the 48SX at the beginning of the 90s. I got one at the time with 1 missing line, and later it developed into 3 missing lines . The elastomer between the display and the PCB was/is defective, it is a sandwich of rubber and some conductive but flexible compound.

I used to apply some failure locating spray to the edge of the display, and because both compounds have different coefficients of thermal expansion you can see if the problem is there, the lines become visible.
***

Looking at the photos http://s1189.photobucket.com/user/_rs1n_...sort=3&o=8

It looks like they were for the conductive foil ( ), well apply so pressure between the foil and the PCB and see if the lines reappear, then, some glue may help.

Thanks for the info. With help I disassembled a hp39g and reseated the display connector. The photos look more complex than the 39g. The failure locator spray is a product I have not used. However, I will wait before I attempt to open the hp50g.

[CK1-CK]

(03-23-2016 05:50 AM)cyrille de brébisson Wrote:  Hello,

You have 2 bad contacts between the PCB and the display.

The contact is done using a heat glued/sealed plastic flexible connector.

Most likely, this has been damaged (or the connection has weakened).

It IS possible, if you are super/very careful to fix such things, but it means opening the calculator, possibly also prying the LCD off and then re-heat glueing the connector strip, which is not an easy feat.

Usually, to do so, you place on the strip some non glue non melt plastic isolator (like anti static tape), and use the soldering iron at low temp to tranfert some heat on the connector and glue it...

I have done it once or twice, but it is hard.

Cyrille

I know the post is old, but I have exactly the same problem (see pictures).

Can someone please mark on the picture where I can find the defective spot?

I have a hot air dryer and soldering iron available.

I am thankful for every tip, because I would like to repair the calculator.

[CK1-CK]

and one more picture.

[CK1-CK]

Hello Forum,

I've made several attempts to fix the calculator.

Here's what I've tried:

• Heating the display and display connector with a hot air dryer. Then press the connectors onto the PCB.
• Use of contact oil for the Display-Connectors
• Pressing the connectors at different places on the PCB
  

Unfortunately everything has been without success so far. The vertical stripes on the display are unfortunately still there.

Can you please give me another tip?
Where was the break of the connector in your case?

I do not want to dispose the calculator.

Best regards
CK


Ich nehme gerne auch Tipps in deutscher Sprache entgegen Ich weiß die Fangemeinde ist groß

[RHIX]

I have the same issue. I have about 10 lines on the left portion of the screen which are blank. I've disassembled the calculator and haven't been able to get the contacts which correspond to those columns to reconnect. It's disappointing that my 30 year old 48SX works perfectly but this 7 year old HP50g is now essentially useless. Considering a Prime but I noticed they aren't even on the HP website. I assume the latest model is the V2. Is HP working on something new? I hope we can get our LCD issues resolved.

[CK1-CK]

Is the red or green connector responsible for the vertical stripes? (see pictures)

Probably the red one.



Does anyone know the temperature the plastic strip connector can withstand?
I think at 200° Celsius (392°Fahrenheit) it is too warm and the strip melts.

[RHIX]

I set my soldering iron to about 350-400F and used an 1/8" thick piece of silicone tubing as the insulator. I think the temp on the other side of the silicon was around 180-200F. (Used a laser temp gun to measure the surface temperature) This temperature combined with about 2-seconds of moderate pressure, reconnected glue bond and all 10 of my vertical lines.

I've only worked with the connections you have labeled as "red".

[franz.b]

(03-24-2016 11:11 AM)Alejandro Paz(Germany) Wrote:  [cut]
I used to apply some failure locating spray to the edge of the display, and because both compounds have different coefficients of thermal expansion you can see if the problem is there, the lines become visible.
[cut]

(05-25-2020 08:02 PM)CK1-CK Wrote:  [cut]
[*]Use of contact oil for the Display-Connectors
[cut]

Hi, sorry if the question is a bit off topic, but it is related to the same problem on my 50g. Can you explain / link these products to me? I didn't know it existed and I can't find any trace of it on the web ... Thanks a lot.

[artag]

(09-21-2021 05:24 PM)franz.b Wrote:  Hi, sorry if the question is a bit off topic, but it is related to the same problem on my 50g. Can you explain / link these products to me? I didn't know it existed and I can't find any trace of it on the web ... Thanks a lot.

I assume you've long ago given up or found the answer, but I found this thread and have a similar problem to tackle. I assume they products mentioned are :

https://www.amazon.co.uk/MOTIP-Freezer-E...B015XMW8A4 or similar, and
https://www.amazon.co.uk/Servisol-701-10...B000KEB6WW

Although I probably wouldn't use that cleaner which is just an oil in alcohol but instead something like

https://caig.com/shop-item/deoxit-d-series/

which i think has a better cleaning action and a residue that isn't just an insulating antioxidant oil since unlike a plug-in contact there isn't enough pressure to displace it.

I'm unenthusiastic about the cleaner but the freeze spray won't cause new problems and is an interesting thing to try. I have more confidence in the heating suggestions.