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[WP-34S] Cable and flashing options for Mac users
01-22-2015, 08:55 PM (This post was last modified: 01-23-2015 12:41 AM by John Galt.)
Post: #62
RE: [WP-34S] Cable and flashing options for Mac users
(01-22-2015 08:00 PM)BarryMead Wrote:  ... the TX of the Prolific Cable must connect to the RX of the calculator (JP5), and the RX of the Prolific Cable must connect to the TX of the calculator (JP6). Also the GND must connect to the calculator's Negative battery terminal (The top of the battery is Positive), so you want the battery terminal that touches the bottom of the CR2032 coin cell.

Yes, that's very helpful. Unless I am mistaken that confirms how I connected it, however, I have not disassembled the calculator and have made no connections other than to the six externally accessible "pogo pin" pads. And, the battery of course.

A picture certainly helps, and the one I've been using is jebem's one here (thanks again Jose):

[Image: Flash_box_hp_30b_sch_proto_001a.jpg]

Referring to that diagram (omit the rest of the circuit, which is not present):

Prolific cable -> calculator

Green -> 1k resistor -> J35 (upper left)
White -> 1k resistor -> J33 (upper center)
Black -> coin cell center conductor (ground) (but I also tried J34)
Red -> no connection

Quote:One of the HP-30B calculators that I modified had a "DEFECTIVE" zero ohm jumper on JP5 or JP6 I don't remember which one it was. Use your ohmmeter to see if both sides of these zero ohm resistors are connected to each other.

That's very helpful! I will do that. If either one was broken (defective), flashing attempts using the programming port would obviously fail. I have been putting off disassembly, awaiting $1 worth of 9ยข clock crystals, apparently stuck on the slowest boat to ever depart Shenzhen.
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RE: [WP-34S] Cable and flashing options for Mac users - John Galt - 01-22-2015 08:55 PM

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