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HP Forum Archive 15

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HP-41CX - Clock does not appear!
Message #1 Posted by Tom Summer on 2 Jan 2006, 3:18 p.m.

I have a problem with my hp-41cx: the clock will not appear after I clicked 'Shift' and 'On'. the hp-41 however obviously is on, because after the next click 'On', I can turn it on again and/or it would accept the 'DELETE' function per '<-'. the clock itself works, which means the command 'TIME' gives the current time into the x-register and all other functions of the Time-module work properly, too. What to do to display the clock permanently? Probably one component on the platinum is defective - only which one? Can anyone help?

      
Re: HP-41CX - Clock does not appear!
Message #2 Posted by Gileno on 2 Jan 2006, 3:23 p.m.,
in response to message #1 by Tom Summer

new batteries! ! ! ! :-)

            
Re: HP-41CX - Clock does not appear!
Message #3 Posted by Tom Summer on 2 Jan 2006, 3:26 p.m.,
in response to message #2 by Gileno

Just kidding, ehh?? Of course the batteries are new, all functions of the calculator work properly - even the card reader, which has the highest power consumption.

Edited: 2 Jan 2006, 3:26 p.m.

                  
Re: HP-41CX - Clock does not appear!
Message #4 Posted by Randy on 2 Jan 2006, 4:05 p.m.,
in response to message #3 by Tom Summer

Try reseting it. Warning: This will clear memory.

  1. Turn the unit off
  2. Press and hold the backspace key
  3. Press and release the ON button
  4. Release the backspace key

The unit should now be on and display MEMORY LOST

                        
Re: HP-41CX - Clock does not appear!
Message #5 Posted by tom summer on 3 Jan 2006, 6:19 a.m.,
in response to message #4 by Randy

Hi Randy,

Thank you. I did this already before I posted the problem. MEMORY LOST appears. Unfortunately without further success.

Best wishes, Tom

      
Allow me a silly question? (was: HP-41CX - Clock does not appear!)
Message #6 Posted by Vieira, Luiz C. (Brazil) on 2 Jan 2006, 9:45 p.m.,
in response to message #1 by Tom Summer

Hi, Tom;

if your answer is "No, I do not allow you a silly question!", please, do not read... It may be considered a silly question, anyway! <8^(

although it seems silly, I cannot help asking it: are you sure it is an HP41CX?

Please, prior to blame me for that question, just let me ask a few others: Is it a newly bought unit, that you have never used before? Did [SHIFT][ON] work properly before? Have you tried [CAT] 2 and checked for the headers-only, CX-style catalog output?

I'm asking these all because it is not hard to hardwire the Time and the X-Functions modules inside a regular HP41CV and 'transplant' its guts to a CX case.

Again, please, if this is not the case, forgive me. I have seen some weird 'hacked' models that called my attention to what can and cannot be done...

Will you forgive me?

Cheers.

Luiz (Brazil)

            
Re: Allow me a silly question? (was: HP-41CX - Clock does not appear!)
Message #7 Posted by tom summer on 3 Jan 2006, 4:34 a.m.,
in response to message #6 by Vieira, Luiz C. (Brazil)

Hi Luiz,

Thank you for your posting. I never would quote it as a silly question, because I did a transplantation from CV to CX and viceversa with other hp-41's, too. But this one is a genuine HP-41CX. [CAT2] shows the CX-ROM Version and the extended CX funktions.

In another post I learned that disconnecting the cardreader without shut off the HP-41 could cause this problem. I bought this one used, so I did not know anything about its 'history'.

Best Regards, Tom

                  
Re: Allow me a silly question? (was: HP-41CX - Clock does not appear!)
Message #8 Posted by Francois on 3 Jan 2006, 3:23 p.m.,
in response to message #7 by tom summer

Hi Tom,

Try the CLOCK function. I think it works like the SHIFT ON.

Best regards

François

                        
Re: Allow me a silly question? (was: HP-41CX - Clock does not appear!)
Message #9 Posted by tom summer on 4 Jan 2006, 3:59 a.m.,
in response to message #8 by Francois

Bonjour François,

I tried this, too. But the command [CLOCK] shows the same effect - same problem.

Thanks, Tom

                              
Re: Allow me a silly question? (was: HP-41CX - Clock does not appear!)
Message #10 Posted by Chan Tran (USA) on 4 Jan 2006, 9:29 a.m.,
in response to message #9 by tom summer

When you xeq the clock function what happened? Just nothing happened or the calculator display "nonexistent"?

                                    
Re: Allow me a silly question? (was: HP-41CX - Clock does not appear!)
Message #11 Posted by tom summer on 4 Jan 2006, 9:38 a.m.,
in response to message #10 by Chan Tran (USA)

Hi Chan,

the function [XEQ][CLOCK] causes the same effect as [SHIFT][On]. The display becomes empty: no signs, no characters. Pressing [<-] the display shows the content of the X-Register again.

Thanks, Tom

                                          
Re: Allow me a silly question? (was: HP-41CX - Clock does not appear!)
Message #12 Posted by Michel Beaulieu on 4 Jan 2006, 8:48 p.m.,
in response to message #11 by tom summer

I think you will have to open the calculator in order to "celan" the contact between PCB's. In fact, just opening it and moving the two halves of the calculator can fit it! PAY ATTENTION to plastic posts; the yare very fragile so don't screw them in to much...

                                                
Re: Allow me a silly question? (was: HP-41CX - Clock does not appear!)
Message #13 Posted by Tom Summer on 9 Jan 2006, 3:48 p.m.,
in response to message #12 by Michel Beaulieu

Hello Michel,

last weekend I opened the calculator again and cleaned the contacts. No success. But another phenomenon became obvious: Once pressed [Shift][On] or [XEQ][CLOCK] the calculator cannot be shut off totally anymore?!? After [Off] any key turns the HP-41CX on and further to that: [<-]+[On] does not lead to 'MEMORY LOST'. To make the calculator working normally, batteries have to be removed for a few seconds. But the above mentioned problems (no clock ...) remain.

Best regards, Tom

                                                      
Re: Allow me a silly question? (was: HP-41CX - Clock does not appear!)
Message #14 Posted by Hans-Joerg Gessler on 11 Jan 2006, 1:21 p.m.,
in response to message #13 by Tom Summer

My question: Did the "BAT" indicator appear in the display? - With my 41cx it's exactly then that the clock won't be displayed (for avoiding too much power consumption)! In my opinion you possibly & simply should recharge the batteries or replace them by new ones.

Good luck, Hans-Joerg

                                                            
Re: Allow me a silly question? (was: HP-41CX - Clock does not appear!)
Message #15 Posted by Tom Summer on 14 Jan 2006, 5:58 a.m.,
in response to message #14 by Hans-Joerg Gessler

Hi Hans-Jörg,

the BAT-Indicator is off. I used new batteries (let's say, they were sold to me as new ones ...). Does it also occur when the BAT-Ind. is off? If so, I'm going to buy new batteries.

Best regards, Tom

      
Re: HP-41CX - Clock does not appear!
Message #16 Posted by David Smith on 13 Jan 2006, 12:15 p.m.,
in response to message #1 by Tom Summer

I have seen this when either the clock crystal or the 22 megohm resistors in the clock circuit are bad.

            
Re: HP-41CX - Clock does not appear!
Message #17 Posted by Tom Summer on 14 Jan 2006, 6:02 a.m.,
in response to message #16 by David Smith

Hello David,

Thanks for this important information. Due to the fact that the clock itself seems to be ok ([TIME], [SW] e.g. work properly) this could be the reason of the problem. I am going to open the HP-41CX again...

Tom

            
Re: HP-41CX - Clock does not appear!
Message #18 Posted by Tom Summer on 15 Jan 2006, 11:20 a.m.,
in response to message #16 by David Smith

Hi David,

Two more attempts to make the HP 100% working:

1. fresh batteries --> no success 2. I replaced the resistor (the old one did have about 26 MegaOhm), the new one has exactly 22.0 MOhm --> no success.

Very frustrating. Do you really think the clock cristal could be bad however [TIME] and [SW] work properly?

Tom

Edited: 15 Jan 2006, 11:21 a.m.

                  
Re: HP-41CX - Clock does not appear!
Message #19 Posted by David Smith on 15 Jan 2006, 11:32 a.m.,
in response to message #18 by Tom Summer

If TIME and SW are actually working properly, then your problem most likely is the firmware ROM. I know that if the clock crystal has problems, you don't get the clock display.

I had one machine where the clock was very flakey and would not come on from the power switch. It would come on from the keyboard. Apperently it was a bad CPU contact. Pressing the keyboard keys pressed down on the CPU card enough to get contact for a short time, but the clock stopped if you touched the machine.

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