HP 42S odd behavior and a temp fix.

[d4days]

I pulled a 42S out of a box of calcs I have (collect waaaaay too many), and decided to use it again. I put fresh batteries in it, but nothing. Rechecked all three battery voltages and all's good. Did the "touch battery contacts together" thing to discharge any residuals. Put batteries back in. Nothing. Tried the E+ and XEQ with the ON button and finally got a "MEMORY CLEARED", but buttons did not respond. Took batteries back out and did everything again. This time nothing. Slightly flexed the machine (I'll try anything once) and E+ and XEQ and ON, then got "MEMORY CLEARED". But, keys not responding yet. Tried every button, and the SIN and square root buttons worked. ?? The number 8 worked and 7, but 7 had to press a little harder. To make a short story long, I found that if I apply a little pressure to the calc just above the top row of keys, but below the display...between the square root and LOG buttons, all the buttons work without excess pressure..! So, what's going on here? I assume something is loose or something. Thanks in advance for your help and for listening/reading.

[Diego Diaz]

Hi,

HP-42 keyboard is of the membrane type and the contacts with the CPU board are held in place by a pressure sponge (no hi-tech whatsoever). This pessure tends to get weaker as time goes by.

With this arrangement keyboard malfunction in the long term is a common failure for this series.

Regrettably, the only way to properly fix such problem requires to take the calculator apart to replace the sponge with a tighter one, which is not an easy task and often leave marks or dents in the case.

Sorry about the bad news.

Best regards from Caribbean.

[d4days]

(05-27-2016 03:39 AM)Diego Diaz Wrote:  Hi,

HP-42 keyboard is of the membrane type and the contacts with the CPU board are held in place by a pressure sponge (no hi-tech whatsoever). This pessure tends to get weaker as time goes by.

With this arrangement keyboard malfunction in the long term is a common failure for this series.

Regrettably, the only way to properly fix such problem requires to take the calculator apart to replace the sponge with a tighter one, which is not an easy task and often leave marks or dents in the case.

Sorry about the bad news.

Best regards from Caribbean.

Hmm. I was hoping to not open it up, but, in the back of my mind, knew it was probably necessary. Thanks for the info.

[rprosperi]

(05-27-2016 11:30 AM)d4days Wrote:  I was hoping to not open it up, but, in the back of my mind, knew it was probably necessary. Thanks for the info.

Contact Adam Jones (AJ04062 here on the Forum) if you'd like to have it repaired for you, he does this kind of work. The hard part of any Pioneer repair is getting the case apart and back together without scarring the case or seams; I can verify Adam does these repairs with no sign of having been touched when done. Good Luck.

[d4days]

(05-27-2016 12:48 PM)rprosperi Wrote:  

(05-27-2016 11:30 AM)d4days Wrote:  I was hoping to not open it up, but, in the back of my mind, knew it was probably necessary. Thanks for the info.

Contact Adam Jones (AJ04062 here on the Forum) if you'd like to have it repaired for you, he does this kind of work. The hard part of any Pioneer repair is getting the case apart and back together without scarring the case or seams; I can verify Adam does these repairs with no sign of having been touched when done. Good Luck.

Thanks! Will look into.