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Bricked hp30b wp34s
05-18-2014, 03:09 PM (This post was last modified: 05-18-2014 03:12 PM by thedanielm.)
Post: #1
Bricked hp30b wp34s
Got a usb to serial adapter like this http://www.ebay.ca/itm/271355948797?ssPa...1497.l2649 to flash my 30b with wp34s. I took the back off and soldered wires for the serial connection to the adapter. I didnt have batteries for the calculator (and i had the back off so I dont think a battery would have stayed in there anyway) so I used the 3.3v from the adapter to power up the calculator. With power from the adapter the calculator was functioning and then at some point the screen went blank before I did any of the flash procedure. I may have inadvertently erased the firmware or maybe a wire crossed and fried something.

I have tried to resurrect it by following the flash procedure numerous times using the flash tool (on both windows xp and linux machines) but no luck. If anyone has any ideas let me know. I've already read all the threads on here from guys who thought they bricked the calculator. I know I have the right port selected in the flash tool because the adapter flashes a couple times when it tries to connect to the calculator. The response is always failed to connect.

Or if there is anyone from canada on here who would like to see if they can resurrect it I would be willing to send it to you.. i'm about to toss it in the trash anyway and start with a new one. This is really bothering me since I have spent a lot of time playing around with arduino - who thought a simple reflash would be so difficult?
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05-18-2014, 04:10 PM (This post was last modified: 05-18-2014 04:47 PM by jebem.)
Post: #2
RE: Bricked hp30b wp34s
From your description, I don't think you had the opportunity to flash it.
The message from mySamba is just telling that it cannot talk to the calculator.

However, if you did the ERASE operation, it is normal that the calculator looks "dead" when you power it on.

I would check and eliminate possible causes:

1. Test your usb to serial adapter for good operation:
- Interconnect the TxD and RxD serial pins of the adapter with a 1Kohm resistor to create a loopback connection;
- Open Windows device manager and check for COMx ports; leave it running;
- Plug the usb to serial converter to the Windows PC;
- Windows should recognize the new device and load the correct driver; you will be able to see an additional COMx port in Device manager; take note of that port nb;
- Get a copy of Windows XP Hyperterminal program and run it (well, if you are running Windows XP the tool is there already!); create a new session, and start typing on the keyboad: if your usb to serial adapter is working fine, you should be able to see the typed keys as echoed characters inside Hyperterminal;

2. Test your HP-30B

- Unplug/unsolder any wires from the back;
- If you do not have CR2032 3V cells at hand, get two AAA or AA batteries, connect them in series to have 3Volt (I use a battery holder) and use clip wires to power the calculator: in the cell's holder, the central cell contact is the Negative (-V) and the outer lateral contact is the Positive (+V); both CR2032 3V cells are connected in parallel in the cell's holder;
- power on the calculator to see if it works; if yes, the calculator was not Erased yet; if not, you need to remember if you did the Erase sequence!
- assuming that you did the Erase, take a digital multimeter, select current readings in mA (200mA full scale is enough) and insert it between one of the AA/AAA batteries contacts and the clip wire, to measure the consumed current; power on the calculator, and you should see a number there, like 2 to 20 mA; this indicates that the calculator is probably OK, it is just waiting to be flashed;

3. If points (1) and (2) passed OK, then it is time to try again!

Just to remember, you need to use 3 wires from the serial adapter to the calculator:
- GND (Ground);
- Txd from the serial adapter connects to the RxD in the calculator;
- RxD from the serial adapter connects to the Txd in the calculator;
Additionally:
- I would use two 1Kohm current limiting resistors, one in the TxD and anotther in the Rxd wire.
- I would NOT use the 3.3Volt from the usb to serial adapter to supply power to the calculator: it does NOTsupply enough current! Use the above 2 x 1.5Volt AA/AAA batteries in serial in a battery holder, or the CR2032 cells inserted. That is probably the main reason why the flash operation is not working.

Jose Mesquita
RadioMuseum.org member

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05-18-2014, 04:50 PM
Post: #3
RE: Bricked hp30b wp34s
Thanks for the very thorough reply! I will try this tonight and let you know what I find.
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05-18-2014, 11:15 PM
Post: #4
RE: Bricked hp30b wp34s
I connected 3v from 2 AA batteries. there is no current draw. When I press the power button the amp draw jumps up and then falls back to zero when the button is released

Connecting reset j36 to j31 induces an amp draw of about 4ma, reset button seems to have no effect. I have tried the procedure outlined in the manual but I cannot get the calculator to maintain any current draw (this would be an indication the calculator is ready to be flashed?)

My guess is that I must have shorted something out and fried it.

Any other things I can check? what component would fry in an overvoltage condition? does anyone have a circuit diagram for the calculator?
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05-18-2014, 11:32 PM
Post: #5
RE: Bricked hp30b wp34s
(05-18-2014 11:15 PM)thedanielm Wrote:  does anyone have a circuit diagram for the calculator?
Of course. It's in the 20b Dev Kit. You might like to take a look at this, too.

Dave
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05-19-2014, 01:02 AM
Post: #6
RE: Bricked hp30b wp34s
Seems to me that serial communication is dead. If someone is interested in soldering in the JTAG connector and reprogramming it that way Ill send it for the cost of shipping. If not shes goin in the trash.

Thanks to those who responded. A new 30b is on the way.
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05-19-2014, 01:18 AM
Post: #7
RE: Bricked hp30b wp34s
I am in Halifax and can try to revive it for you if you wish, send me a private message if you are interested.
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05-31-2014, 06:07 PM
Post: #8
RE: Bricked hp30b wp34s
UPDATE: I managed to flash the new calculator and old one.

Here is what worked for me.

Used mysamba instead of the flash tool. I was unsuccessful with the flash tool on both my linux machine and windows xp.

The FDTI serial adapter I was using had a variety of connections. I initially was using the TX and RX pins but switched to using TXD and RXD which worked.

Thanks for everyones help!
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