WP 34s battery problem

[Elite]

Hello,

I know that this has been dicussed but I'm really having problems with the battery:

When I try to enter something the calculator keep dying and after pressing ON shows RESTORED.

I have tried putting new batteries but after two weeks the same symptoms appear rather quickly again.

The batteries are CR2032 GRUNDIG and are supposed to be 200mAh.

When a prorgam with BATT inside is run the result ranges from 2.3 - 2.5, but without load that is 2.9 - 3.0.

I haven't used the WP 34s much, just for quick calculations so I am wondering is the anything that could be done?

Maybe use other batteries?

NB: 34S 3.3 T 3695

[TASP]

Assuming your numbers there are VDC, an LCD calculator should not 'pull down' the voltage of a fresh set of batteries regardless of what it is doing.

(help me out here, that model doesn't have an illuminated display, right?)

Look for corrosion, expiration date on batteries, moisture (bad!) or fess up to taking the calculator apart and modifying it for more computing power.

[robberknight]

(05-05-2015 10:09 PM)Elite Wrote:  I have tried putting new batteries but after two weeks the same symptoms appear rather quickly again.

Since the WP 34s firmware is stable and known not to cause issues like this it sounds like a hardware problem with your calculator to me.

One possible cause could be a crack in one of the ceramic capacitors. That would lead to a higher leakage current and drain your battery.

Do you have a good multimeter with enough resolution and a low milliampere range? Then you could apply 3 volts, keep the calculator in standby, and measure the average standby/off current. If you measure more than about 10µA then there is something broken.

Unfortunately it is not easy to pinpoint the problem to one exact component unless you have a near short circuit. But then the calculator would not show anything even with new batteries.

Did you install the crystal with the capacitors? Maybe the capacitors got a crack while soldering. Ceramic capacitors are quite sensitive to mechanical stress (which can be caused by expansion due to heat during soldering).

[Derek W]

(05-05-2015 10:09 PM)Elite Wrote:  The batteries are CR2032 GRUNDIG and are supposed to be 200mAh....

Maybe use other batteries?

NB: 34S 3.3 T 3695

Before giving up, I would certainly try that. Grundig used to be a respected German manufacturer, but since early 2000s has had owners who mostly seem to have used it as a brand name for equipment sourced from a variety of makers. I haven't encountered their batteries, but I have found that lithium batteries bought in bulk from low-cost shops in UK can have very poor life in some applications, even those with apparently well-known brand names (Kodak and Hyundai are examples).