WP34S Reset during printing

[Christoph Giesselink]

I have a problem with WP34S 3.3<P>3678 newly expanded with IR transmitter LED.

For the IR transmitter I used a SFH409 transmitter LED and a 365Ohm resistor.

When using the <P>STK printer command everything is ok, but when using a printer command with larger output like <P>REGS the printing stops somewhere around the r10 register with a "Reset" message in display. I thought that maybe caused by low batteries and measured the equipped onces (both >3V) and also using new ones, same problem.

Any hints?

Christoph

[Marcus von Cube]

(09-30-2014 06:23 PM)Christoph Giesselink Wrote:  I thought that maybe caused by low batteries and measured the equipped onces (both >3V) and also using new ones, same problem.

Bad news :-(

You can try to increase the printer delay to allow the cells to recover between two lines of output. I tried hard to minimize the power consumption of the IR circuit by generating the pulses with very little CPU intervention but the strain on the cells may still be an issue.

[walter b]

IIRC, a similar problem was reported earlier this year. Since I guess you're well equipped, I'd suggest you power your WP 34S using a 3 VDC source of larger capacity (a larger battery should do) and check if the problem persists. I'll look for that previous case in the meantime.

d:-I

(Just saw Marcus was faster than me.)

[Dieter]

(09-30-2014 07:52 PM)Marcus von Cube Wrote:  I tried hard to minimize the power consumption of the IR circuit by generating the pulses with very little CPU intervention but the strain on the cells may still be an issue.

While we're at it: I wonder if anyone here may use some kind of external power supply for the 30B/34s. Maybe some kind of power pack (with D cells ;-)) or simply an AC adapter. Do you think this would make sense? How could such a power source connect with the 30B/34s hardware?

As far as printing is concerned: I always liked the idea behind the TI 58/59 printer cradles (PC100 series) that also supplied the calculator with energy. ;-)

Dieter

[walter b]

Here's the old thread I remembered: http://www.hpmuseum.org/forum/thread-1773.html

d:-)

[Didier Lachieze]

(09-30-2014 08:00 PM)Dieter Wrote:  

(09-30-2014 07:52 PM)Marcus von Cube Wrote:  I tried hard to minimize the power consumption of the IR circuit by generating the pulses with very little CPU intervention but the strain on the cells may still be an issue.

While we're at it: I wonder if anyone here may use some kind of external power supply for the 30B/34s. Maybe some kind of power pack (with D cells ;-)) or simply an AC adapter. Do you think this would make sense? How could such a power source connect with the 30B/34s hardware?

Dieter

If you have installed Harald's USB board in your 34S you should be able to power it from USB.

[Dieter]

(09-30-2014 08:08 PM)Didier Lachieze Wrote:  If you have installed Harald's USB board in your 34S you should be able to power it from USB.

Ah, yes. I suppose in this case you can also use a simple standard USB AC-adapter to power the device.

Dieter

[walter b]

(09-30-2014 08:46 PM)Dieter Wrote:  

(09-30-2014 08:08 PM)Didier Lachieze Wrote:  If you have installed Harald's USB board in your 34S you should be able to power it from USB.

Ah, yes. I suppose in this case you can also use a simple standard USB AC-adapter to power the device.

Yes you can.

d:-)

[Christoph Giesselink]

TNX for your comments. I increased the resistor from 365Ohm to 432Ohm today, but no success. I still get the Reset message, the only difference to before, the max distance between calculator and printer is now ~10cm less. The good news, the workaround with the ()DLAY command is working.

Seem that I have to look for a high efficiency IR-LED transmitter to fix the problem on it's roots or be okay with the workaround.

Christoph

[matthiaspaul]

If the problem hasn't been solved already, I'd like to suggest a small hardware modification, which should improve the situation by decoupling the IR LED's anode from the power plane and thereby reducing the voltage drops on the CPU's supply rail:

http://www.hpmuseum.org/forum/thread-294...l#pid28498

Greetings,

Matthias