HP Forum Archive 14

[ Return to Index | Top of Index ]

HP-41 Buying Tips Message #1 Posted by Mike on 8 July 2004, 2:22 p.m. I have decided to start including an HP-41 Buying Tips in all my auctions. I'm finding more and more people selling HP-41 calculators as "like new" and "mint" that have serious problems. So, I produced this HP-41 Buying Tips, to inform buyers. I think I may add a comparison chart between the C, CV and CX. But my main focus was letting people know of potential problem areas. What do you think? Anything else I should mention? Edited: 8 July 2004, 2:26 p.m.

Re: HP-41 Buying Tips Message #2 Posted by Mike H on 8 July 2004, 3:21 p.m., in response to message #1 by Mike Great idea, can we link to it? A problem I have seen is broken tines on the charger port cover, chipped corners on the battery case or corrosion on the battery springs. Mike H. 1111

Sure linking is ok Message #3 Posted by Mike on 8 July 2004, 3:31 p.m., in response to message #2 by Mike H I have no problem with anyone linking to the tip sheet. The more that are educated about this, the fewer will be disappointed. I would like to avoid people using the link and simply falling back on "you should have asked", which I have heard from some sellers. I hope this educates sellers as well as buyers. Edited: 8 July 2004, 3:33 p.m.

Re: HP-41 Buying Tips Message #4 Posted by Brian Ayling on 9 July 2004, 4:50 a.m., in response to message #1 by Mike Possibly also worth mentioning dead or intermittent keys. I know there is a possibility of repair using a tiny wire brush, but I had a Halfnut that wouldn't respond to such treatment (dead decimal point key), relegating the calculator to the parts bin...

Re: HP-41 Buying Tips Message #5 Posted by David Smith on 9 July 2004, 1:07 p.m., in response to message #4 by Brian Ayling I've never met a mechanically sound key that could not be fixed using the wire brush technique. Sometimes you have to do it a few times (while preesing and releasing the key). It may also help to use some contact cleaner like DeOxit instead of alcohol.

Re: HP-41 Buying Tips Message #6 Posted by Chan Tran on 9 July 2004, 2:49 p.m., in response to message #5 by David Smith David. Can you elaborate on how to fix the keys using the wire brush technique? I have a full nut CV that has a couple of keys with problem.

Re: HP-41 Buying Tips Message #7 Posted by David Smith on 9 July 2004, 1:10 p.m., in response to message #4 by Brian Ayling Usually the "1" and sometimes the "2" key like to go a bit soft on the earlier machines with the high top keys. Also check the length of the display time out and auto-shutoff features. Also check all the memory. I have a couple of machines with wonky RAM chips. Also check all the ports. Sometimes one (or often pairs) of ports will not work properly.

Re: HP-41 Buying Tips Message #8 Posted by Brian Ayling on 9 July 2004, 8:31 p.m., in response to message #7 by David Smith David wrote : "Also check the length of the display time out and auto-shutoff features." What should actually be checked? On my three 41's the shut off time varies from 8 to 12 minutes. Is that reasonable? Also the TONE frequencies are noticeably lower on one machine, but that is the one with the shortest shut-off cycle. Swapping batteries makes little difference. Since they all seem to function fine, I assume this is all within tolerance?

Re: HP-41 Buying Tips Message #9 Posted by David Smith on 10 July 2004, 4:10 p.m., in response to message #8 by Brian Ayling A fair number of HP41 machines have problems where they shut off after anywhere from 0-30 seconds. Some never shut off. Also some display modules only display while a key is being held down (many times caused by old solder flux on the CPU or display or contamination on the keyboard)

Re: HP-41 Buying Tips Message #10 Posted by Ronald on 11 July 2004, 5:20 p.m., in response to message #8 by Brian Ayling Tone is dependent on the internal clock frequency. The internal clock frequncy is determined by a simple condensator with a tolerance. In the past I used to speed up HP 41 machine's to 175% of the normal speed, consequence was next to a higher power consuption also an linear increase in tone frequency.

[ Return to Index | Top of Index ]

Go back to the main exhibit hall