WP 34S will not turn on

[BarryMead]

(12-05-2017 05:51 PM)brettpim Wrote:  I have PL2303 USB-Serial Port adapter which I used to flash the WP 34S originally. I am powering the calculator with a fixed voltage power external supply at 3V. I have used the reset procedure on page 150 of the manual to erase the firmware and have then tried flashing many times but with no success. I am using

wp34sflashcmd calc_xtal_full.bin /dev/ttyUSB0

with read/write permissions for ttyUSB0

The calculator draws 130 mA as soon as I attach the power supply and pressing the on button does not change this, nor does resetting the calculator. When I short the Vcc and the Erase terminals from the 6 pads the calculator then draws around 730 mA and again this does not change when I press rest nor when I press the on button. Is it correct that the amperage does not change whether the calculator is on or off?

Is there some way to verify if my PL2303 is functioning?

Is there some way to determine the internal state of the calculator?

The current draw of the calculator should go way down to a few micro amps when you press the reset button, and not go into the mA range until after you press the "ON" button. It seems clear that the "Boot Loader" portion of the firmware is corrupted, and that the only way you will be able to resurrect your calculator is to use a hardware flashing device known as a jtag programmer. One can be purchased for about $43 US
and I found a source a while back on this forum. The device plugs into and gets its power from a standard type B USB Printer Cable, and attaches to the JTAG pins of the calculator. I don't own one of these devices, but others
have reported being able to fix dead calculators (those with corrupted bootloader firmware) using this device. The device has other uses as well. It allows you to hardware debug programs and set breakpoints etc.
I found the web page of where to order one I was thinking of. Here it is:

A company named OLIMEX makes a cheaper open-source software version of the ARM JTAG programmer that sells for only $43.17 (39.95 euros). It can be ordered from this web site:
https://www.olimex.com/Products/ARM/JTAG/ARM-USB-TINY/

You may also need the ARM-JTAG-20-10 Accessory to adapt the JTAG pin count to that of the calculator. This accessory costs $4.95 more.