HP35 with "the Bug" and the CHS-EEX - Printable Version +- HP Forums (https://archived.hpcalc.org/museumforum) +-- Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum-1.html) +--- Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum-2.html) +--- Thread: HP35 with "the Bug" and the CHS-EEX (/thread-114441.html) |
HP35 with "the Bug" and the CHS-EEX - Dan W - 05-24-2007 Hi all, I have one HP35 with "The Bug" and one without. The behavior of the CHS key with the EEX key is different with the buggy HP35 than the other. But I haven't found this difference written up anywhere. On the buggy HP35, if I enter a number, then EEX, I do NOT see two digits off to the right until I type them in. On the non-buggy HP35 I see two zeros to the right as soon as I hit EEX. On the buggy HP35 I must hit the CHS key immediately after the EEX key to get a negative exponent. When I do this I get -00 displayed, then I can punch in the actual exponent. But after that the CHS key does not do anything - I can't change the (-) to a (+). On the non buggy, I can enter the EEX digits and hit CHS at will, reversing the EE sign each time. Is this known behavior of some HP-35's or related to The Bug? Or is this a different problem? Thx
-- Dan
Re: HP35 with "the Bug" and the CHS-EEX - Eric Smith - 05-24-2007 I think that was a separate change, which occurred in a release before the famous bug fix. There were at least three public releases of the HP-35 firmware. If you ever have occasion to open them, please note the part numbers on the ROMs (round metal cans, part number 1818-xxxx).
Re: HP35 with "the Bug" and the CHS-EEX - Dan W - 05-25-2007 The ROMs for the one with the bugs are:
K7239FC 1818-0020 The numbers are on the side, not the top. Is there a document describing in detail the different ROMs sold and the bugs or errata in each set? Thanks,
-- Dan
Re: HP35 with "the Bug" and the CHS-EEX - Eric Smith - 05-26-2007 There are at least three public releases, and possibly four. There were internl engineering releases, of which it is possible that some prototype units may exist. Prototypes: combinations including 1818-0001 through 1818-0019 Earliest known release: 1818-0006, 1818-0017, 1818-0020
Intermediate: (unknown, possibly unreleased) Bug fix: 1818-0024, 1818-0026, 1818-0027 Revision, purpose unknown: 1818-0024, 1818-0026, 1818-0028
Peter Monta has dumped the (6, 17,20) set, and a later release that is believed to be the (24, 26, 27) set, so these can be compared in simulation in Nonpareil. At some point it will be a good idea to dump the sets with 27 and 28 for verification.
Re: HP35 with "the Bug" and the CHS-EEX - Dan W - 05-26-2007 Thanks Eric.
This bug affecting the operation of CHS with EEX has much more user impact than the 2.03 ln e^x bug, but is less well known. Was it resolved quickly in an intermediate release before the more famous bug?
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