Looking for HP41CX Advice

[GreyUser]

(08-08-2021 09:24 PM)Massimo Gnerucci Wrote:  

(08-08-2021 07:05 PM)GreyUser Wrote:  The original tall key 41C’s were quite the homing pigeons and most made the trip back Corvallis more than once. It is exceptionally rare to find one in the wild with all original parts.

All of my TK 41s are working, with original parts.
Call me lucky.

I would be very surprised to learn that any 41C was still working with the original pink elastomeric cpu board connectors. The resistance new was usually around 1K and just like carbon composition resistors, the resistance goes up over time. The battery connection pin is the only one that matters since it’s the only one with any appreciable current being passed through it.

[Neve]

(08-08-2021 09:58 PM)GreyUser Wrote:  I would be very surprised to learn that any 41C was still working with the original pink elastomeric cpu board connectors. The resistance new was usually around 1K and just like carbon composition resistors, the resistance goes up over time. The battery connection pin is the only one that matters since it’s the only one with any appreciable current being passed through it.

Pardon my ignorance, but to be perfectly honest with you, I have no idea what pink connector you’re referring to. But I trust you. Do you happen to have any pictures that would enlighten me?

Cheers

[GreyUser]

The HP41 cpu connectors, oldest to newest, left to right.
           

[Massimo Gnerucci]

(08-08-2021 09:58 PM)GreyUser Wrote:  

(08-08-2021 09:24 PM)Massimo Gnerucci Wrote:  All of my TK 41s are working, with original parts.
Call me lucky. :)

I would be very surprised to learn that any 41C was still working with the original pink elastomeric cpu board connectors. The resistance new was usually around 1K and just like carbon composition resistors, the resistance goes up over time. The battery connection pin is the only one that matters since it’s the only one with any appreciable current being passed through it.

My own first TK (1953A) - I know since I had to open it for cleaning - had the second type connector, not the pink one.
I don't know what's inside the other three. Maybe the pink one is in the 1930A unit (that reliably works, BTW)...

[aurelio]

(08-08-2021 09:24 PM)Massimo Gnerucci Wrote:  

(08-08-2021 07:05 PM)GreyUser Wrote:  The original tall key 41C’s were quite the homing pigeons and most made the trip back Corvallis more than once. It is exceptionally rare to find one in the wild with all original parts.

All of my TK 41s are working, with original parts.
Call me lucky.

+1 Massimo

I've "transformed 41or CV in CL, never TK , not only to have the more performing LCD, but also to not sacriface my few TK: I'm not a frequent visitor of TAS but I remember that pristine older 41s were not so easy to find like the newer models. Better to keep in a drawer a CX or a CV board unused than to have a wonderful CL with a darker display.

[Neve]

(08-09-2021 12:18 AM)GreyUser Wrote:  The HP41 cpu connectors, oldest to newest, left to right.

Thanks for the picts.

From memory, my one and only TK has the middle connector.

[Neve]

(08-09-2021 11:47 AM)aurelio Wrote:  +1 Massimo

I've "transformed 41or CV in CL, never TK , not only to have the more performing LCD, but also to not sacriface my few TK: I'm not a frequent visitor of TAS but I remember that pristine older 41s were not so easy to find like the newer models. Better to keep in a drawer a CX or a CV board unused than to have a wonderful CL with a darker display.

I personally don’t mind. To me, there’s no point in keeping an entire calculator in a drawer. I’m not a collector, and they’re meant to be used. The slightly darker LCD isn’t really an issue, and won’t, in any way, keep me from using the calculator.
Sure the later LCD’s are a bit brighter and look a bit nicer, but that’s not a dealbreaker for me. I actually like the feel of the taller keys. They feel more positive. Whatever rocks your boat, I guess. Everyone is different.
On a side note, I wouldn’t mind at all a TK with a later LCD.