|Hyper HP-41 Speed-Up by Synergistic Design|
Message #1 Posted by Dan Grelinger on 14 Aug 2008, 11:02 a.m.
I installed a "Hyper-41" Double Speed Upgrade from Synergistic Design (purchased through Educalc) in my HP-41CX halfnut in February of 1988. Over the years, I had noticed that the batteries would deplete much more rapidly if the calculator was left in the normal speed setting while turned off. It is also impossible to change the batteries without the clock losing its time when left in the normal speed setting. This has contributed to a little corrosion on my battery contacts because the batteries deplete within a couple of months, even if I am not using it. It is especially problematic because the hyper-speed toggle micro-switch on the side of the HP-41 can be accidentally pressed when interting the calculator into its case, unknowingly toggling the speed setting.
I finally rigged up a multimeter to measure battery supply current for my HP-41CX, and was able to verify that the calculator is using quite a bit more current in normal speed mode versus 'hyper mode'. When the HP-41CX is off, and left in hyper mode, supply current is between 10 and 30 microamps. When left in normal speed mode, supply current is between 710 and 720 microamps, an obviously big difference. If I assume that an alkaline N-cell has a current capacity of 800 mAh, I calculate that at this increased current, a new set of cells will deplete in 47 days when left off.
I vaguely remember reading/hearing that one 'feature' of this speed conversion pacage was that an LED was included on the board that would light up in one of the modes, and could be seen through some spot in the calculator case. I have assumed that it was this LED indicator that was causing the increased current use when switched in normal mode. But, when I tried to view light shining from the case, I could not see anything, even in a completely dark room with my eyes adjusted to the darkness.
I still have the original box and instructions for the speedup kit, and examined the documentation last night, but could not find any mention of this LED indicator. I looked up Katie's 1988 Educalc catalog and read the description for this speed conversion unit, but there was no mention of an LED indicator. I don't think I dreamed this up, but I don't remember exactly where I saw it, or even if it was for this particular unit. It might have been info I got when calling Educalc for support on this issue, but I don't remember.
Does anyone else have experience with this particular speed up conversion kit that they could share? I scanned the forum archives and could not find any pertinent info.
BTW, except for this problem, this speed up has worked well for me over the years. My HP-41CX runs just a tad over double speed with it. It works well with many of my modules, even my Advanced HEPAX. The documentation recommends against using it with HP-IL, more than two doubled modules, or a nearly full port extender. I have a triple module (Advantage + 2 XMem)that seems to cause problems if another module is installed in the HP-41 as well, and the XMEM does not work reliably regardless. I also noticed that most of the older (single) XMEM modules work just fine at double speed, but that most of the newer ones do not. I recently purchased a NoV-32 from Diego (what an amazing little device!), and it does not work at double speed, the machine locks up when turned on. I think he specifies it at 1.7 X normal speed.