The Museum of HP Calculators

HP Forum Archive 06

[ Return to Index | Top of Index ]

41CX: strange display problem
Message #1 Posted by Harald J. Schulz on 17 Oct 2001, 12:04 p.m.

My new 41CX (halfnut, S/N 26...) seems to be a little bit confused: It displays none of the announciators (Flags, Shift, G/Rad, User, Prgm) other than Alpha. But: in Alpha-Mode, all is working fine, shift, flagstate, rad etc. pops into display. Unfortunatly all is gone again after leaving the alpha-mode...

Any ideas how to fix this annoying behaviour? Discharge to a "memory lost" doesn't help.

      
Re: 41CX: strange display problem
Message #2 Posted by db(martinez,california) on 17 Oct 2001, 11:37 p.m.,
in response to message #1 by Harald J. Schulz

it IS confused, isn't it? i took my half nut out and once in alpha i couldn't get into program without it shifting out of alpha or play with flags, or xeq anything. however user could toggle. i don't know about this but mabye you could try a soft reset. it couldn't hurt but discharge to a memory lost should do whatever this will. press the back arrow and enter keys and hold them then press on and let up on all three. good luck; someone here will probably know what to do.

            
Re: 41CX: strange display problem
Message #3 Posted by Vieira, Luiz C. (Brazil) on 18 Oct 2001, 7:13 a.m.,
in response to message #2 by db(martinez,california)

A hunch:

Is it possible that the COMMON connection for the other annunciators (PRGM, USER, G RAD, flags) is "lifted" (not connected) and, somehow, when ALPHA is lit, this connection is stablished by ALPHA potencial?

I have seen this kind of not-normal opperation in signaling panels using LEDīs and lamps switched by transistors, never in LCDīs. Sometimes, when both COMMON connectors are lifted AND stay connected each other, this may happen if switched voltage is not the same. 41īs LCD, as all others, operate with three voltage levels.

I would also guess bad internal display connections. Did any battery leak?

                  
Re: 41CX: strange display problem
Message #4 Posted by Harald J. Schulz on 18 Oct 2001, 2:28 p.m.,
in response to message #3 by Vieira, Luiz C. (Brazil)

"I would also guess bad internal display connections."

Sounds possible, i will check that if the seller give me his OK. I hoped it was a simple software- or user-problem but it seems to be more serious.

"Did any battery leak?"

Unfortunately ;) not, its in nearly mint condition, and i will be really sorry if i have to return it. My working-horse-CV looks (and feels, thanks to one loose screw-post(?) i have to repair really soon) quite ugly against this lovely CX...

                  
Re: 41CX: strange display problem - a correction
Message #5 Posted by Vieira, Luiz C. (Brazil) on 18 Oct 2001, 4:33 p.m.,
in response to message #3 by Vieira, Luiz C. (Brazil)

Excuse-me, all.

"41īs LCD, as all others, operate with three voltage levels"

should be:

"41īs LCD, as many others, operate with three voltage levels"; some new LCDīs use four voltage levels.

"Sometimes, when both COMMON connectors are lifted... "

should be:

"Sometimes, when TWO OR MORE COMMON connectors are lifted "

Thanks.


[ Return to Index | Top of Index ]

Go back to the main exhibit hall