Pioneer LCD problem or feature!

[Mark Edmonds]

Hi folks,

I recently got an old 17B II for a song - in good condition except a strange feature in the display.

Firstly, the LCD is dark even when the calc is off and viewing angle is narrow when operating. Slight annoyance.

Secondly, the odd thing is that you can read some text through the LCD. The text is in the top right hand corner of the display, mirrored in relation to the calc and reads: "3-A7088B-DL NOSPE" on the top line and "C374M" just beneath. Neither of these lines obstruct the actual display segments.

Reversing the text gives: "EPSON LD-B8807A-3", "M473C". Presumably, this is the component name for the LCD?

The calc cannot have been opened in the past.

Anyway, the point of me mentioning this is can it be got rid of? I am wondering if the LCD has suffered a bit of high pressure or temp extreme during its life which is why it is dark and this text shows through.

Has anyone come across this before or can offer any advice please?

Thanks! :)

Mark

[Randy Sloyer]

That's not a feature, it's a fault...

I have seen it many times. The LCD was cooked at high temperatures and either the polarizer or liquid crystal material has failed or it could be both. It's toast, literally with total replacement being the only solution.

There was a reason why it a bargain :(

[Mark Edmonds]

Thanks for your reply Randy.

Do you know - does this mean the display is going to decay further and might go dead completely or will it remain as is unless I do something stupid to it?

Thanks

Mark

[Randy Sloyer]

With the ones I've seen, they're relatively stable with no further deterioration over time.

The Epson number you see from the front in reverse is the part number printed on the back of the device. Normally it is not visible but the opaque layer is gone and it has become a transmissive LCD, not reflective. Unfortunately, the polarizer is damaged as well so restoring the reflective coating will still leave you with a bad display. Been there, tried it.

[Mark Edmonds]

OK, appreciate your help here Randy. I'll leave it as it is and to be honest, the 17bII hasn't excited me so far. At least I've learnt a lesson to watch out for in the future!

Mark

[Martin Pinckney]

Randy,

Along the same line of questioning (about Pioneer displays, that is), my 27s has two verticals lines of inactive pixels. Is this fixable? Thanks,

Martin

[Randy Sloyer]

Missing vertical lines are usually a damaged LCD so yes, it should be repairable.

[Frank Boehm (Germany)]

but a problem with the contact strip - this is usually fixable by cleaning the strip, the display and PCB *and* taking care, there is enough pressure applied when reassembled. In some cases, the line driver has failed - this is not fixable.