Delmhorst J2000 calibration

[tacks Y]

I was looking at a used J2000 and was told if battery goes dead it will mess up the calibration. Has any one had this problem? Did you send it in? Do you have the MCS 1 to check calibration? Thanks

[YellowHammer]

Nah, I don't believe that.  I've had my battery die many, many times, in several J2000's and never had a problem.  A dead battery is how I know to change them.  

As a confirmation, the J2000 series comes with an interanl shunt calibration resistor, and when selected, will provide an instant reading of accuracy.  

Make sure it's got a good battery, hit the calibration buttons and if the meter displays 12%, it's good.  

Its possible that an internal malfunction will cause a dead battery and will also display an incorrect reading, but that is a different situation.  It wasn't caused by a dead battery, it just ain't working right.  I've had that happen.  

[WDH]

Like YH, I replace the battery when it is dead and there is no issue with calibration. 

[tacks Y]

Thanks guys. I had called Delmhorst and that is what the rep told me about buying a used one. He suggested I buy the MCS1 for $40 to confirm it was working right.

[YellowHammer]

I read that in the manual years ago, and checked the manual yesterday, and jogged my memory, but had forgotten about it until this topic.  It never made sense to me, so years ago, I called them up about it, and had them explain the reason why it could come out of calibration.  At that time they couldn't (I never got in contact with the right technical guy).  I assumed their amplifer circuit would come off baseline and they could not correct for it. However, they did explain the internal calibration routine, and it's the same as the MCS1, in that a reference resistor, equivalent to the resistance of wood at 12% MC, is put in the system by pressing buttons on the J2000, and if the meter is functionjng correctly, it will read 12%.  The internal shunt resistor has only one value, equivalent to 12%,  however, the external shunt resistors in the MCS1 have two calibration resistors, so can check at two points on the curve, 12% and 22%.  

I used to return all my J2000's for yearly factory calibrations, and I never had one that that didn't meet factory cal if the built in, internal shunt resistance calibration check was correct and read 12%.   However, if the internal shunt check was wrong the unit was bad.  Generally, if the unit is bad, it's obvious from the display, it reads "FFF" or similar.  No way to miss that.  So, personally, I'd have full confidence in buying a unit simply by checking the internal shunt calibration installed in the meter and then sticking it in a piece of wood in a house (probably at 7% or 8% to make sure the physical probe mounts and connectors were good, and to give a second confidence check) After all, that's why they installed the internal shunt cal option, and that's why I stopped sending them in for factory cal, plus it was expensive.  

However, the MCS1 will work at two points instead of one, so it might be a good investment to have traceability, and would be useful for that.

The issue of the unit becoming damaged when when the battery dies is a manufacturer issue and should never happen, because any battery operated unit must be expected to lose battery power many times in its service life.  So they need to fix this, but personally, I've never had it happen.  What would happen if a cell phone stopped working correctly every time the battery died? Or a smoke detector?  

Most of the J2000 failures I've had come from other issues, such as cracked display, cracked plastic handle, loose sensor connections, push buttons that stop working, etc.  I also had issues with freezing and condensation.  I stopped sending mine in for repair every time they failed, they charge $100 minimum for repair, no matter what's wrong and once broke, they keep breaking.  So I just have them on One Click ordering on Amazon.  The best way to keep them working is to bring them back into the house in an air conditioned environment when not being used.  

[xlogger]

sorry to change the subject some but it time for me to order some new pins for my slide hammer. any other places cheaper than from Delmhorst? 

[tacks Y]

Thank you Yellowhammer for taking the time to explain this.  Tom

[GeneWengert-WoodDoc]

The original meters used electronic tubes and required adjustment from time to time, as well as calibration every use as the battery changed voltage.  We used to adjust the X and Y values manually.  I suspect it involved temperature sensitivity of the equipment as well.

 The external shunt resistor and most meters were calibrated for four needle probes originally, at 12% and 22% MC.  As we developed transistor and printed circuit boards, the stability of the components improved.  So, it is rare to ever have small calibration change today and recent times.  Battery voltage is also controlled so even with weak batteries, the meter still works.  This is not true with cheap meters however.

What does change is the resistance within the probe wire and connections, now and then.  Also, when a cool meter is taken into a humid kiln, the humidity on the older components or within the wires or 26E probe can give you bad readings.  So, having an external resistor check at 12% MC is a good idea.  The internal check will not catch probe issues.

[tacks Y]

Thanks Gene.

[tacks Y]

Ok I now have the J2000 and hammer probe. Checking wood at 6 to 8%. Not pushing in very far 1/16 to 1/8". Is this far enough? Tried the hammer to 1/4" or more, is this far enough? Reads are close, not much sun. What should I shoot for? The kiln dried wood in my shop is about the same. What do I need, more sun? More fan time? Thanks      

[GeneWengert-WoodDoc]

What are you trying to measure?  To get the average MC, the insulated needles need to go about 1/4 of the thickness.  To get the core MC, halfway.

A typical MC target for hardwood lumber when it leaves the kiln is 6.8% to 7.2% MC.

Although the meter may read 6% MC, any reading under 6.5% MC could be drier.

Do you get around 22% to 30% MC when you touch both needles with your fingers at the same time?

[YellowHammer]

Tacks, not sure what you are asking?

[tacks Y]

Seems hard to push in, did not want to break. With red oak should I be able to push in farther? The hammer slide I can beat in farther. So I want to shoot for 6%. I checked a pile air drying at around 12%. So to get to 6% should I just crack the vents and run the fan when hot? Will try with my fingers. The hammer reads .1 to .2% higher,  so wetter farther in? This is all on the edge of 4 quarter.  Thanks 

[GeneWengert-WoodDoc]

When going into the edger face with the short needles fastened to the case, you are measuring the surface MC, which does not tell you the MC further in.  If you have oak, and the surface is dry, it is indeed difficult to get the needles that are fastened to the case into the wood very deep.  Plus, being uninsulated, the measure the wettest MC, so that means on a foggy morning you will get a higher reading even though the average MC has not changed, compared to measuring the wood when the humidity is low.

You, therefore, should almost always use the hammer probe with insulated needles.  It measures the MC where the tips are.  Replace the needles when the coating begins to wear off.  With dry oak, the needles do break.  So, the 1/2" long needles are better than 1" long.  As many times the core MC is critical, drive the needles into the face of the lumber, not the edge.

You mention cracking the vents.  Is the lumber in a kiln?  Is it solar heated?  To achieve the lowest MC in a solar kiln, the vents are only opened a very slight amount.  In a kiln that is not tight, but has a few small leaks, the vents can be fully closed the last few days.  Fans are run only when the kiln is hot...maybe 10AM to 5PM.

Remember to make the temperature correction, which is the temperature of the wood, not the air.

[tacks Y]

Yes the wood is in my solar kiln. Still trying to learn how to use it. I have not been running the fans much, thought that is what I read here some where. It was air dried for years. Will run the fans more and check the face. Thank You

[xlogger]

I went of of town this weekend and when I got back I went down to test a load of walnut slabs, battery was dead so I put in new battery. Like Robert said I've done this several times with no problem. But this time it gave me negative reading. When I just hit the button is doesn't read 12 anymore, I got it in front of now and it's showing -5.7. This is the first time it's ever gave me problems. I put in wood here in house and it shows 7.6 which I would think its correct.
Just when back outside and recheck walnut again, looks like its about right. I've got it in the heat cycle around 145-150 degrees and getting an average reading of 7.8 with the high at 9.5. But its still showing -4.5 with testing here not in any wood. Not sure how much I should depend on it?
So Robert you just suggest getting a new one? I see on Amazon they are $360. Do you still send your old one in or just toss it or would a call to Delmhorst do any good?

**update, just got off phone with Danny, best phone call I've made in awhile. He directed me in the correct way to check and nothing is wrong with my Delmhorst, thanks again Danny.

[YellowHammer]

What did you do?

[WDH]

You have to mash both buttons at the same time . 

[xlogger]

You have to mash both buttons at the same time .

Some how I forgot and only pushed one. I'm getting more and more forgetful the older I get. Like when I open the vents so it would not over heat and forgot to cut vent on. :-[  

[YellowHammer]

Yep, hitting both buttons at the same time will fix the problem. :D :D 

Same with setting the electrode type.

My unit has lots of black Sharpie marks on it, including black lines drawn between buttons to activate functions.  I also write the species numbers on the unit. 

In this day and age of plastics molding, there is no reason for Delhmorst not to actually mold the shortcuts and species numbers into the handle of the unit.

Since they don't, I just write them on there with permanent ink.
   

[Stephen1]

Hold it! Which 2 buttons? I missed reading something.
I find I need to be a lot younger to figure which button to push after and for how long ???

[WDH]

The moisture content button and the button below it with the check mark on it.