[Interest Check] FK-5001/9000 calculator replacement

[thefarside]

I’m also interested and curious if the calculator on the FK-8000 would be compatible with this project.

[forter4]

I'm also interested. Just acquired an FK-5001 with a non-working calculator

[smleeeeee]

I’d be interested as well. Just got a 5001

[kelvinhall05]

IMG_2884.JPG (2.26 MiB) Viewed 5180 times

[dodddummy]

I got an FK-9000 and would definitely buy this calculator module.

[engr]

Any news on this project? I got an FK-9000, FK-5001, and FK-8000 with calculator issues... Would love to restore all of these.

[kelvinhall05]

Any news on this project? I got an FK-9000, FK-5001, and FK-8000 with calculator issues... Would love to restore all of these.

[engr]

Sorry, best I can do is $50 try and replace electrolytic capacitors in the PCB and hope that was the cause of some calculator issues on Focus boards (which is what I am hoping to try within the next couple of weeks). Anything more complex than replacing components is currently beyond my comfort level.

[kelvinhall05]

Sorry, best I can do is $50 try and replace electrolytic capacitors in the PCB and hope that was the cause of some calculator issues on Focus boards (which is what I am hoping to try within the next couple of weeks). Anything more complex than replacing components is currently beyond my comfort level.

The issue has nothing to do with capacitors. The conductive adhesive used to attach the display ribbon gets weak with age, effectively disconnecting the display. I've experimented with new adhesive but it's nearly impossible to apply it in a way such that no contacts are bridged but there's enough to keep the ribbon attached.

I keep toying with the idea of making mine open source, but quite frankly the idea of having to inevitably do tech support for a bunch of DT boomers who can't read instructions really turns me off.

[engr]

The issue has nothing to do with capacitors. The conductive adhesive used to attach the display ribbon gets weak with age, effectively disconnecting the display. I've experimented with new adhesive but it's nearly impossible to apply it in a way such that no contacts are bridged but there's enough to keep the ribbon attached.

"‘All functioning Focus boards resemble one another, but each broken Focus board is broken in its own way" - Leo Tolstoy on keyboards, probably, 1878.

My FK-5001 has a glitch where the calculator works fine when using the keyboard plugged into PC, without a battery. When powered from a battery, however, it turns off once I enter too many digits. I am guessing it has something to do with PCB, and the capacitors seemed like a low hanging fruit to check first.

It's a shame these Focus boards have so many issues, because functionality-wise they are amazing.

[kelvinhall05]

The issue has nothing to do with capacitors. The conductive adhesive used to attach the display ribbon gets weak with age, effectively disconnecting the display. I've experimented with new adhesive but it's nearly impossible to apply it in a way such that no contacts are bridged but there's enough to keep the ribbon attached.

"‘All functioning Focus boards resemble one another, but each broken Focus board is broken in its own way" - Leo Tolstoy on keyboards, probably, 1878.

My FK-5001 has a glitch where the calculator works fine when using the keyboard plugged into PC, without a battery. When powered from a battery, however, it turns off once I enter too many digits. I am guessing it has something to do with PCB, and the capacitors seemed like a low hanging fruit to check first.

It's a shame these Focus boards have so many issues, because functionality-wise they are amazing.

I have played with dozens of these calculators and they all fail in the same way lol. The problem you're describing is independent, though I still feel it's not related to capacitors, as the battery is ultimately on the same power rail as the 5v from a PC, just separated with a diode and resistor iirc (I don't have an original board on me to check). If it was a cap problem it would affect it all the time.

[engr]

I have played with dozens of these calculators and they all fail in the same way lol.

Now that I'm looking at it... I don't understand how exactly this ribbon is electrically connected to the display in the first place. I am not seeing any connecting terminals on the LCD side, it's like it's just glued to glass. Are there just transparent strips of conductive glue leading from the ribbon conductors to the LCD?

[kelvinhall05]

I have played with dozens of these calculators and they all fail in the same way lol.

Now that I'm looking at it... I don't understand how exactly this ribbon is electrically connected to the display in the first place. I am not seeing any connecting terminals on the LCD side, it's like it's just glued to glass. Are there just transparent strips of conductive glue leading from the ribbon conductors to the LCD?

The problem is PCB-side, not display-side. If you looked very close with light at the right angle you would see traces running in the glass.

[engr]

The problem is PCB-side, not display-side. If you looked very close with light at the right angle you would see traces running in the glass.

So this method will not work on the PCB side?

[kelvinhall05]

The problem is PCB-side, not display-side. If you looked very close with light at the right angle you would see traces running in the glass.

So this method will not work on the PCB side?

I don't have tools like that at my disposal so I couldn't try it. Don't see why it wouldn't work.

[dodddummy]

Is there are update on whether this will happen? I'm ready to give you my money.