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HP 41C strange model - Damien MATTEI - 12-13-2008

hello,

collecting calculators i find some difference beetwee HP41C,
we know already it exists early version with tall keys,and later versions with rounded corners,but what do you think of an LCD display
having one white dot at each corner? i'm owner of one of those,does any one else got one? i think yes on ebay as i find one just selling this week:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=190273646012&indexURL=1&photoDisplayType=2#ebayphotohosting

i suppose it exist a lot of them anywhere in the world...
does any one have an explain about that?

regards,

damien


Re: HP 41C strange model - Nelson M. Sicuro (Brazil) - 12-13-2008

My HP-41CV ("full"nut, coconut) uses the same display. It loks like a little glue dot or spacer or a backplane contact (at least three of them). And for some bizarre reason, mine hasn't a serial number... I have restored it from at least two part sources (front and back from different calcs) and the back part really do not have a serial number. Did anyone saw something like that?

Best regards,

Nelson


Re: HP 41C strange model - Allen - 12-13-2008

Here's
one I had with White dot display


Re: HP 41C strange model - Damien MATTEI - 12-14-2008

hello,

mine is same with one white dot at each corner at the place where some hp41c have rounded corner,i wondering if the model has been repaired, if the dot where existing behind the rounded corner ones and if parts could have been taken from the LCD display to repair another model but it doesn't seems as the soldering on mine is really perfect from factory.
I just wanted to know if HP made some model with the 4 white dots showing in the LCD or if it was result of a repair?
Personnaly i find that not esthetic at all and i'm asking if the model with white dots where selling or if it was some repairs or a transition model beetween square corner and round corner.
I never heard anyone else talking about that in forums so i wanted to know.

Another things i noticed opening many HP41C are the difference in the design of circuit ,the 'motherboard' from one model to another of the same year or more could be really different,not simply the electronic components that belongs from different manufacturer but the place of chips on the circuit,really amazing.

regards,

damien


Re: HP 41C strange model - Randy - 12-14-2008

There are six different processor board layouts that where used over the life of the product. They are all well documented in the full 41 service manual available from TOS.

While they are not as well documented as the boards, there were at least three different versions of the LCD, the hybrid display driver and interconnects. While most are interchangeable, there are some incompatibilities, both electrically and mechanically.