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Odd HP-35 Red Dot
09-28-2017, 12:15 PM (This post was last modified: 09-28-2017 12:32 PM by jebem.)
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RE: Odd HP-35 Red Dot
(09-27-2017 11:55 PM)aj04062 Wrote:  Well I picked up this Red Dot the other day. I am confident in saying this even though it looks like a V4 HP-35.
...
To my surprise it is an early board (note 03-72 date plus 1211 marking).


It's always a pleasure to look to these machines internals and reconfirm the high quality of the 70's technologies.

Mine is not a red dot for sure.
Also it has got a PCB date code of 40 73, and one of the ROM ICs is marked with 7344 (1973 week 44):
http://4.bp.blogspot.com/-pyNvbIEGkAY/VC...M_7888.JPG

But looking to your PCB, it seems that at least one of the ROM ICs is marked as "7303" (1973 week 03).
Would this still qualify it as a red dot?

Can you check if some of the ICs solder joints where manually re-soldered?
If yes, then probably someone have rebuilt it in 1979....

Edited to add this:
Does your machine have the famous "exp(ln(2.02) = 2" bug of the early firmware?

Jose Mesquita
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Messages In This Thread
Odd HP-35 Red Dot - aj04062 - 09-27-2017, 11:55 PM
RE: Odd HP-35 Red Dot - jebem - 09-28-2017 12:15 PM
RE: Odd HP-35 Red Dot - aj04062 - 09-29-2017, 09:56 PM
RE: Odd HP-35 Red Dot - Dave Frederickson - 09-29-2017, 11:21 PM
RE: Odd HP-35 Red Dot - aj04062 - 09-29-2017, 11:53 PM
RE: Odd HP-35 Red Dot - Dave Frederickson - 09-30-2017, 01:08 AM



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