HP 35 ... top row buttons


Hi everyone,

I recently purchased on TAS a complete, fine looking 4th version HP 35 s/n 1346A 46XXX. I never fully appreciated, until having examined one, the fine design and construction of this pioneering electronic slide rule (especially the battery door design with sliding clasps/pads). The only cosmetic deficiency is some wearing off of the silver paint above the OFF/ON switch. It is a very nice addition to my collection and will be used as well!

It works well except for the top row of keys which need to be pressed quite forcefully to register. I knew this when I purchased it so no surprises there. The 'on' switch is a little touch and go also, and the x^y and LOG keys are the hardest to get to work consistently. The e^x works the best of the lot (top row only). I believe all of the above issues are related. Seems to be a case of poor contact and shouldn't be a difficult repair job - once I figure out exactly how to do it.

I am not an expert HP calculator electronics tinkerer, having only taken apart a Spice model successfully using the fine explanation at Spice Repair to add some foam to increase pressure on the circuit card. If Geoff Quickfall's book will be out soon, hopefully he can put me on his list of buyers....

In the meantime, can anyone (Geoff??) recommend a repair method for this beauty? I do not want to cause any damage to it! It is my 15th HP RPN model and I guess I will have to start maintaining them on my own at some point.

Thanks! ----- Jeff Kearns


Maybe this is the best link for me to use: HP 45 Restoration . Any other suggestions? -- Jeff


Any other suggestions?

Not sure if it will add anything to Geoff's information, but
this thread might be worth a look.



Jeff -- Your post (which I had seen at some point) is likely the info I am in need of.

Once I get enough courage to peel that label back without damaging it, I will disassemble my 35 and clean it up.


Jeff Kearns

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