|An unusual HP 71B - questions|
Message #1 Posted by Doug (NYC) on 14 Jan 2013, 6:44 p.m.
I recently purchased another HP 71b in trying to complete my "perfect 71." However, this 71b was very unexpected and has some unusual characteristics. I don't know what it is; it's some sort of Franken71 and hopefully you can help me identify what's going on.
1. Why does my new 71B have 168,443 RAM and VER$ has "FTH:1A EDT:A KBD:B" when all 6 slots are empty?
2. Why can I add only 4K extra RAM with software modules or lots of RAM but no software modules?
(Now, I read http://www.hpmuseum.org/cgi-sys/cgiwrap/hpmuseum/archv007.cgi?read=13392 but didn't entirely understand it. This might be the answer to #2.)
With everything removed (all 6 ports including front) and batteries, the calculator reports the following:
VER$: HP71:1BBBB FTH:1A EDT: A KBD:B
Now, as I recall, a stock 71b should be reporting about 16k of MEM and just the HP71:XXXXX in the version. So, I have one that strangely has over 160k of RAM and Forth. (It is because it had Forth I purchased it; I wanted a Forth module, but this is not a module!) I am not sure what KBD:B means. It passes the ROM self-test (ON-/, 2).
It also came with a module that looks blank but with a golden label with no writing. This module when inserted modifies calculator to:
VER$: (as above) WB:D TXTU:A
WB is the 71b spreadsheet. I'm not sure what the TXTU:A is. It also came with a CURVE FIT module. Adding that adds in a "FIT:A" to the VER$ response. Then, adding the HP-IL module that it came with adds "HPIL:1A" to the VER$. Those are expected.
Next, I add a 96k card reader RAM module to it, but the calculator now gives me an error: "WRN: Configuration" when I start it up. MEM now reports 266,697, but the VER$ now shows "HP71:1BBBB FTH:1A EDT:A KBD:B HPIL:1A WB:D TXTU: A" so the FIT:A is no longer being seen. Removing the 5061-7241 CURVE FIT still results in the 71b saying "WRN:Configuration."
Removing both modules, so that the only things installed are the 96k card reader RAM module and HP-IL module causes the warning to go away. MEM is still 266,734.
In the next test, I now add a 32k module (Front slot, Corvallis) and again now I get the WRN. Nonetheless, the RAM seems to be accepted, as MEM reports 296,546 and VER$ reports "HP71:1BBBB FTH:1A EDT:A KBD:B HPIL:1A". Adding another 32k module now shows 329,356 MEM, and VER$ shows only "HP71:1BBBB!" and continues with the warning. Adding 4k modules one at a time shows more memory each time, but now there's just RAM.
If I take out the 96k card reader RAM module, I can then put in all my other modules (HP-IL, Math, Curve Fit, and the strange WB/TXTU) without an error. VER$ reports HP71:1BBBB FTH:1A EDT:A KBD:B HPIL:1A MATH: 1A FIT:A WB:D TXTU:A" so it's all being seen, with MEM of 168,338. Adding a 32K module to the front will return the WRN:Config error, but the VER$ is the same as before and MEM is 201,106 as expected, so I'm not sure what's now the problem.
Replacing the 32K with a 4K reports MEM of 172,429 and no configuration problems!
Unfortunately, I have no more software modules to test, no card reader module to test (I'd love to get one), and I imagine the 64K RAM card reader module I have would do the same thing as the 96K module given the results with the 32K front port module.
So, what's this odd 71b I have? And what's with the "too much RAM" WRN problems?