Wanted: 49G+ w/ 3rd rev. keyboard

[Massimo Gnerucci]

(07-01-2014 06:31 PM)HP67 Wrote:  

(07-01-2014 06:29 PM)Massimo Gnerucci Wrote:  Because it's from april 2006!

Darnit! Now my only hope is to get you to paste it from google groups since none of the other servers I know of retains it that long.

Thanks, Massimo.

Here we go! But you should do something for this Google idiosyncrasy...

I don't normally post to this newsgroup, but I do read everything. However,
I feel the point has come where I need to settle some things.

There has been a lot of misinformation over the years about the keyboard in
the HP 49G+. I have used a large number of 49G+ calculators and every
single ROM, so I feel I am in a good position to analyze the different types
of keyboards, so I will try to set things straight as best as I can.

First, as most of you are aware, the problems in the 49G+ keyboard have been
caused by both hardware and software.

The very first 49G+ units had an absolutely terrible keyboard. These were
all made in 2003 (mostly CN33 and CN34 serial numbers), and they are easily
identified by the loud, hollow clicking sounds when pressing keys. The keys
required a significant amount of force to press, and missed keystrokes were
common. The keys also frequently broke under use that most would not
consider abuse.

The manufacturing process for the keyboard appears to have been changed at
the end of 2003. The first unit I used with the second-generation keyboard
had a serial number starting with CN352. This later keyboard required less
force to press and was quieter than the original keyboard. However,
reliability was only slightly improved, with missed keystrokes still common
and the "loose tooth" broken key problem at least as bad as before.

Most readers of this group probably have 49G+ calculators with this
second-generation keyboard, as it was produced for about a year and a half.
All CN4 and CNA4 units, as well as the early CNA5 units and a few very late
CN3 units, have the second-generation keyboard.

The third-generation keyboard was introduced in mid-2005. I have seen
several units with CNA515 serial numbers with the third-generation keyboard,
but I have also seen several CNA52 units with the second-generation
keyboard, so it seems to have been slowly introduced. All CNA534 and later
units that I have used have had the new keyboard.

The third-generation keyboard is easy to detect. The plastic used in the
keys, as well as the mechanics behind the keys, have both changed. I do not
know whether there are any units with only one of these changes, so there
may be some hybrids out there, but I have not seen or heard of any.

The new plastic is a lot more flexible, and it makes the keys significantly
more durable. It would take a large amount of abuse to damage the
third-generation keyboard, so broken keys should be a thing of the past.
This new plastic can be identified visually, as the plastic itself is
slightly smoother, and the key labels are slightly less shiny. The keys now
have metal domes behind them, which make them feel a lot like HP
48SX/GX-style keys. Key travel is slightly shorter, and they feel more
responsive. They are also far more reliable, so no keystrokes should be
lost in normal use.

The newest keyboards have been available on the retail market in the US for
the last few months, so calculators purchased this year may be of the new
design.

This means the hardware problem has been definitively solved, which brings
us to the software problems.

The early 1.2x 49G+ ROMs were a disaster, and many keystrokes were lost
somewhere in software on those ROMs. It doesn't really matter if they were
lost in the operating system (Kinpo OS) or the Saturn emulator, because the
49G ROM never saw the keystrokes.

ROM 2.00 Build 50 changed the key handling, meaning that individual
keystrokes were no longer lost in software. However, there was so much
variation within the apparently large manufacturing tolerances in the
keyboards that its keybounce settings were rarely appropriate. Many users
reported either doubled keystrokes (keybounce time set too short), and other
users reported having the second keystroke in an intentionally doubled
series being missed (keybounce time set too long).

Various 2.01 builds tried different keybounce timings, but due to the poor
hardware in the first and second-generation keyboards, nothing worked
perfectly for everybody.

ROM 2.05-4 Build 88 brought back the KEYTIME commands. This allowed the
user to set the keybounce timing in 20-millisecond increments, so it could
be set appropriately for any hardware. This was the first ROM that could
truly be considered reliable for keyboard entry. Of course, this assumes it
is being used on reliable hardware.

The new, third-generation metal dome keyboard does an amazing job at
eliminating keybounce. Setting the KEYTIME to as low as 160 ticks (that's
just 20 milliseconds) still has no bounce, and buttons can be pressed as
fast as humanly possible with no missed keystrokes.

In summary: Get a 49G+ with a serial number of CNA534 or higher, install ROM
2.06, and you should never have any more missed keystrokes or broken keys.

Regards,

Eric Rechlin