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HP-41cx Won't Power Up - Printable Version

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HP-41cx Won't Power Up - pwright - 05-13-2020 02:28 PM

Greetings,

I have just acquired an HP-41cx and it won't power up after the long trip from California to Florida in a UPS truck. The unit did work fine about a week ago.

I've tried all of the tricks listed in the Forum Archive short of taking the device apart and will try them again.
https://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/articles.cgi?read=149

As to taking it apart and cleaning the flex circuits that doesn't look difficult but I am concerned about removing screws in 40 year old plastic. The '41cx is in pristine condition and I would really hate to crack the case removing screws.

Is there anything I'm missing? Any advice is appreciated.

Cheers


RE: HP-41cx Won't Power Up - Allen - 05-13-2020 11:59 PM

are there any gaps between the top and bottom halfs? You can try squeezing along all corners and see if the case halfs compress together and come apart causing a gap.

Some models will fail to power on if the top interal posts are broken (causing the battery terminals to lose contact with the pcb.) other models will fail to power on if the bottom posts ( behind the R/S key and x key ) fail to connect the motherboard to the flex connector with enough pressure.

With the calculator laying flat, it's possible to apply pressure on the keybord face on all four corners with 4 fingers on one hand, and with the other hand try the ON or ON+ <- + ENTER reset procedures.

Sadly this is quite common with the fragile plastic of these models to be get cracked internally in transit. I also received a HP41 this week with a broken post behind the R/S key and discovered it using the same method above.

(you are also right, that it's practically guaranteed to crack the case if opened, this vexes me greatly.)


RE: HP-41cx Won't Power Up - pwright - 05-14-2020 10:35 PM

Thanks Allen for the reply. The case of this example is very solid but I've decided to send it back. It would be unfair to the seller to damage the plastics and ask for a refund if the operation wasn't successful. hopefully I'll be able to find another one.

Cheers