The Museum of HP Calculators

HP Forum Archive 18

 HP 34C batteries with AA 1.5V cellsMessage #1 Posted by Damien MATTEI on 1 Sept 2008, 4:33 p.m. hello, i find a post saying that use of AA 1.4 volt cells could damage the contact by breaking them, in my opinion it is true but i find a method to avoid that, use a hammer to stike lightly on the positive end of the cell will crush (make it flat) it in a way it will not hurt the connection on the HP , so the 1.5 volt will have same length that the 1.2 volt rechargeable batteries. After doing that check that cell as no leakage. it works great.(i made it using energizer cells) power is 3V with two cells ,i assume that it is not too much for calculator as a lot of people use it without having reported problems other than the possible breaking of batteries contact which can be avoided with this method. another issue i had with my hp 34c is the misfunctionning of a key (the dot key) ,after opening calculator i find there was a contact problem in the plastic bubble containing contacts for this particular key as the others keys on column and row of the dot key was working well,even if the aluminium of contact seems perfect,it needed an extra pressure, adding 4 or 5 peice of sticking paper beetween the bubble and the key solve the problem . note that this method is working for a solderless unit regards, damien

 Re: HP 34C batteries with AA 1.5V cellsMessage #2 Posted by Les Wright on 10 Sept 2008, 3:18 a.m.,in response to message #1 by Damien MATTEI Damien, for some reason the idea of interfering with the integrity of the battery casing by weakening it by even a gentle whack makes me uneasy. I far prefer to use standard length NiMH cells with a thin bit of foil completing the circuit. I am careful when I insert them--straight in, not an angle, push gently, and so far the connections have survived. I have a 33C too with a snapped connector but there is enough of a stub left to complete contact. I don't use the little metal sleeve to complete the circuit when using standard size AA batteries. Makes everything a little too thick and snug. I also recharge the cells in the calculator. This may not be best for the batteries in the long run, since the old charger wasn't designed for newer NiMH cells, but I would rather have the batteries last a little less long than risking breaking anything by taking them in and out to charge elsewhere. Les

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