blue chip resetter canon - can they go bad?

[PeterBJ]

ROX wrote:

...PeterBJ - I'm not really too familiar with a multimeter but I do have one. Can you tell me how to test with it? When I have time to tinker with it, i'll try it. I'd like to confirm what it is thats wrong...

I found a couple of tutorials here: http://www.youtube.com/watch?v=bF3OyQ3HwfU and here: http://learn.adafruit.com/multimeters/overview . If you are not too familiar with electricity/electronics be very careful. If you try to test voltage with the multimeter wrongly set to measure current you create a short circuit. Also mains voltage is dangerous, and some batteries like a large automotive 12V battery can create very high short circuit currents, several hundred amperes or maybe more than a thousand amperes! Even an AA NiCad or NiMH cell can create enough current to burn thin wiring. If you know somebody who is familiar with electronics, I suggest to ask him or her to demonstrate the use of the multimeter.

barfl2 wrote:

Mine is the Redsetter bought I think from Octoinks had it about 18 months used regularly but do not do massive amount of resets. I took bottom off and it has a 3V Mitsibuishi battery CR3032 type. This should be a reliable manufacturer. I once was told by a local retailer that you should NOT check voltages of these button cells with a volt meter they had a seperate gadget they used

I think you will have years of trouble free service from your Redsetter. The battery problems seem only to affect the very first models.

The reason for the advice that a voltmeter is not suited for testing batteries, is that the volt meter draws only a very small current, which could give a false good indication. The battery has an internal resistance causing the voltage to drop under load. When a battery is is getting used up, the no load voltage decreases and the internal resistance increases. The internal resistance may increase faster than the no load voltage drops. So the voltage should be measured when loading the battery with a suitable current. For testing the CR2032 I think a load resistor of 680 ohms will be suitable. This will draw approximately 5mA from a good CR2032, The 5 mA is approximately the current drawn by a newer model Redsetter when in use. I think that as long as the voltage of the battery is more than 2.8 V or 2.9V under load the battery is still good for use with the Redsetter. I think the special device is just a simple voltmeter in parallel with a suitable load resistor and housed in a small box.

 

[Tandberg]

The retalier got it right, the voltage (without any load applied) only tells you
the cell might be OK. The simplest battery tester at least uses a load to
see if the cell can deliver current. If the load is matched to the battery type
and size the test is even better.

A low voltage without load menas the cell is dying.

Some cells leak a tiny bit and the corrosion on the battery holder can give the
same problems as with a bad cell.

Keeping the (new) battery and the holder clean increases service life. A fingerprint
on the insulating part of a watch battery can draw as much current as the watch itself.
Battery powered resetters will probably use a switch to connect the battery or go into
"hibernate mode" after a preset time. In both cases the battery life should be close to
the storage life if you don't use the resetter frequently.

Disclaimer:
This information comes from areas with designs very similar to resetters, I'm using a
USB powered type myself. The engineering braincell avoids batteries with unknown
status if possible.

[darn - PeterBJ was quicker]

 

[PeterBJ]

Here is a scan of my first generation Redsetter with a 2xAA battery box attached using double sided sticky tape, click to enlarge.



The two alkaline AA cells show a no-load voltage of 3.19 V dropping only to 3.17 V during a reset, indicating that the internal resistance is much lower than for the CR2032 Lithium cell. I hope that battery problems are now a thing of the past with the alkaline cells. In my opinion the added battery box doesn't make the Redsetter less convenient to use.

I could also have made the Redsetter USB powered by using 3 silicon diodes like 1N4001 in series with the USB 5 V supply voltage. These diodes are rated for 1 A and the current that can be drawn from a USB port is limited to 500 mA. An overloaded diode can short out, meaning that the voltage drop will be zero, the use of 1 A diodes makes this approach more fail safe. Remember to add a load resistor like 1 k Ohm across the battery terminals to keep the voltage down. The 0.6 V voltage drop across a conducting silicon PN junction is only a rule of thumb, actually this voltage drop is current dependent, and for low currents it tends to go towards 0 V meaning that you will have almost 5 V across the battery terminals. The voltage should drop immediately when current is drawn, but does the Redsetter contain any capacitors? Better play it safe and include the load resistor to protect the Redsetter from overvoltage.

The reason I chose the battery box instead of using a USB cable from a defunct mouse + 3 diodes and a resistor, is that I like the "cordless" resetter much more than the USB powered versions. I think the USB cable is an inconvenience. If you don't mind the USB cable I recommend buying a USB powered resetter for long trouble free service.

Strictly speaking a battery is made from two or more cells, but the use of the word "battery" when you actually mean a single cell is sometimes more convenient and commonly used, both in Danish and English.

 

[pebe]

Hi barfl2

Thanks for the Maplin tip, I will check that out.

What brand/model of resetter are you using?

I think that the high power consumption only affected the first PGI-5/CLI-8 Redsetters, later models didn't have this flaw. In spite of the early Redsetter's appetite for batteries it has served me well for almost five years.

As a resetter is an important tool for a refiller of Canon cartridges, I think that other people's experiences with different brands and models of resetters would be valuable information.

Mine is the Redsetter bought I think from Octoinks had it about 18 months used regularly but do not do massive amount of resets. I took bottom off and it has a 3V Mitsibuishi battery CR3032 type. This should be a reliable manufacturer. I once was told by a local retailer that you should NOT check voltages of these button cells with a volt meter they had a seperate gadget they used

Your local retailer was right. A digital multimeter effectively measures the battery voltage off-load. Best use a 150ohm 1/4watt resistor to put a 20mA load on the battery.

Use the crocodile clips of your multimeter, connect it across the resistor (either side of the body) then bend the wire ends of the resistor round to contact either side of the battery.