Help programming WP 34s

[John Galt]

Here are a few preliminary thoughts that might go toward minimizing any unknown factors.

1. If you prefer Linux that's ideal as far as I'm concerned. What I don't know about Windows would fill several books, with several chapters devoted to "com ports" alone.
2. Therefore all my programming efforts used Ubuntu Linux and Wine. Linux-specific instructions: How to Install Wine on Ubuntu 18.04 Bionic Beaver. I followed them explicitly, it worked perfectly, so I did not perceive a need to document anything specific. If you have any Linux / Wine related questions they're probably already addressed in that other thread. Your knowledge of Linux certainly eclipses mine, but please ask if anything is not abundantly clear.
3. I attempted to flash the calc using programs other than MySamBa, but none of them worked. At least one of them should not be hosted on the Sourceforge site because its output bore no resemblance to anything that could possibly work. As I understand the HP30b, timing is critical. MySamBa has been reliable for me so I recommend sticking with it.
4. The calc's power supply is also critical. Maintaining adequate and correct voltage throughout the flash cycle is required. Your desire to power the calc through J31 instead of relying upon possibly weak batteries is good, and I agree with it, but you might want to consider using your bench power supply. One less thing to worry about. (Edit: see this post. The programming pad itself is inadequate to power the calc, at least with the pogo pins I’m using. So use your power supply.) I bricked one calc due to what I suspect was a Vcc power interruption during a flash cycle. Admittedly I had to work at it though, demonstrating it's difficult but not impossible to brick one. I've programmed and reprogrammed hundreds of times and that was my only casualty. Conclusion: Make it effectively impossible to lose power while flashing it.
5. Suggestion: I lost an embarrassing amount of time trying to figure out why I couldn't make my system work. In the end the culprit was incorrect documentation for my $1.79 USB to serial device, whose labels for Tx and Rx were swapped. That was it. Color codes mean zip so don't rely upon them. You can't possibly harm anything by switching Tx / Rx, so try it. I recommend using a 1k resistor in each to obviate concerns about possible level differences.
6. Observation, using my bricked WP34s: MySamBa sends three short but distinct bursts of data to the calc at about one second intervals before it gives up. That takes about three seconds, during which the Windows "Send File" button remains "down". This same timeout will occur if you neglect to turn your calculator on before attempting to flash it. On the other hand if MySamBa cannot even get so far as to access its designated "com port" then the "Error Unable to connect" dialog appears immediately. This observation may help you to determine where the problem lies.

Worst case scenario: Won't be in time for Christmas, but (assuming you're in the US) you could always send it to me and I'll flash it.

Or, confirm it's really dead :-(