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Hp-46 printer problem - Printable Version

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Hp-46 printer problem - Maximilian Hohmann - 07-04-2007

Hello!

I have searched the archives already, but only found a reference to a possible power supply capacitor failure that might cause printing problems in an hp-46. If this is not the cause with my units (I will check it tonight), what other problems/solutions are known?


In my case, I have two otherwise fully working hp-46 calculators, both with the LED display option, that share the same printing malfunction: The paper advance only works sporadically, if at all. From the outside I suspect a worn drive roller or belt or non-engaging clutch. The working principle of the paper advance mechanism can only be guessed without disassembling the printer and I am a bit reluctant to do so, especially if there are no spare parts anyway...


Greetings, Max


NB: Sooner or later, because they take up too much space (says my wife) I will have to part with one of them - so if anyone is interested, watch the classifieds section! (I prefer trading to selling and could throw in a nice 41CX as well)


Re: Hp-46 printer problem - Tony Duell - 07-04-2007

You can get 'my' schematics of the HP46 from The Australian Site. The logic board diagrams show the circuit that operates the feed solenoid, you might just check that's working correctly, but I am pretty sure your problem is mechanical.

From what I remember (and it's been a few years since I've been inside the 46), the feed solenoid in the printer engages a follower on the main camshaft, and it's the force of that cam rotating that operates the feed ratchet. My guess is that there's hardened grease somewhere in the mechanism so that it doesn't snap over as sharply as it should. Unfortunately I've never stripped a 46 printer (I did a similar printer in a Fluke data logger about 20 years ago...), so I can't tell you just what to take off.