Gem Pro 250

[savageshooter86]

Ok just got my GP 250 last week and had it set up and calibrated. Just a couple quick questions for anyone who uses one. Did the linear calibration and the std calibration to verify scale. Wiped everything down with dryer sheet and also have the line filter by the AC plug and one also by the plug on the scale end of it.

1) What weighting mode do you use? 0001 or 0002.......

2) I place the powder pan on and tare it out and it gives me 56.10 gr. Weigh some charges and then it will start reading 56.15 when I take pan off BUT when I put it back on there it still is showing 0.00 gr?

Any help on these 2 things for me

 

[CoverDog]

First off the 0001 & 0002 are for jewelers using it for carate weight of diamonds. Just leave it set on the 0001.

Second, if your scale is giving you a reading with a 5 at the end when you have it set to weigh in grains you don't have a GemPre 250 you must have a GemPro 500 with GP 250 markings. Your 250 will always have an even number as the last number (0,2,4,6,8) since it weighs to 2/100th's of a grain.

I'm a little confused about your tare method. You say you place the pan on the scale the "tare it out" and it reads 56.10. I think the reading is before you hit the tare button not after. Once you place the pan on the scale it should read your 56.10 but once you hit tare it should read 0.00 If the scale reads 0.00 with the pan on that is correct, but if you remove the pan it will read 56.10

The pan that came with mine weighs 62.48 but I don't use it. I use a pan that I had from an RCBS scale that is aluminum. It weighs 222.60

Hope this helped....

 

[savageshooter86]

it is a 250 but when I change the weighting mode it will read in even numbers at the end. manual says to use 0002 mode for most accurate weighing but that makes the last number read 5.

Sorry I do the weight pan as you described. I just wasn't sure if it was a concern if it reads 0.05 gr different when pan is off sometimes, but once I put it on it reads 0.00

 

[CoverDog]

The instructions that talk about 0001 & 0002 are in dark print and talk about the two Carat modes of weighing. I take this as instructions if you are weighing in Carat modes.

Which ever mode you use either 0001 or 0002 you final weight will only be off by 1/100th. of a grain. Since the scale is accurate to 2/100th's I chose to have my last number end in an even number

 

[savageshooter86]

OK I will change mine to weigh like you mentioned to the last digit being even. I was thinking that would be more accurate but confusion came from the instruction manual. like you said, that is referring to carat mode only I believe

 

[savageshooter86]

if I put pan on scale and it weighs 56.10 gr and tare it out. Then weigh something and take pan off to dump and the scale now reads something different sometimes. Usually within (0.2-0.6 gr.) As long as when I put pan back on and it reads 0.00 am I good? Not sure why it varies sometimes but it does

Thanks

 

[Luke_NL]

I have found the same issue with my GP250, although -and perhaps you meant to say the same thing- the negative weight (after taring with the pan) displayed when the pan is lifted varies by .02 - .06 grain. I do (have to) tare out every other few trickled up throws, does that sound familiar / right? I'm thinking at this level of accuracy it might be the cell-phone and computer nearby, vibrations in the surface it's on, temperature or some other variable, the other thought I had is that the placement of the pan isn't necessarily identical every time. Will see if I can fix that by glueing a plastic coin or so (fitting in the scale's recessed center) on the underside of my pan to ensure centered placement every time. I'll update when I get my mitts on something that fits.

 

[SDDasher]

What I can deduce from using the GemPro 250 for about a month is that you cannot rush the process of weighing the powder once on the scale. It takes a few beats for the scale to weigh out. If you remove the pan and place it back on the scale it will give you an accurate reading quicker than if you just wait for it to "finish" weighing.

As an example suppose you seek a weight of 32.2 grns and you trickle with a Phoenix trickler the last 0.2 grains. As you trickle the scale takes a few beats to account for the added individual grains falling from the Phoenix. If you know each kernel like Varget or H4895 weighs 0.02 you can count the kernels to reach the desired weight. However it takes the scale a few seconds to "catch up" with the count and measure the weight accurately. So my advice is to be patient and allow the scale to function as it was designed.
I have found the picking up of the pan and replacing it the most effective was to move the process along a little. Hope this helps some.

I have also found that removing the pan before completing the weighing process makes the reading instead of going to "0" when the pan is removed to read anywhere from 0.01-0.08. If you let the process complete it will go back to 0.00 every time.

 

[savageshooter86]

I weighed out 20 charges yesterday on it and only had 1 time I had to tare(other than doing it on my own every few charges or so) due to it not returning to 0 after putting pan back on.

I too have noticed to give it a good few seconds even after it says it is done weighing before taking it off the scale. It is doing a lot better this way. I have noticed the little pan they give you is very hard to handle if you have big hands so putting exactly same spot on scale each time takes some effort.

Thanks for the posts to verify. I guess there is a small learning curve with the unit to get it consistent

 

[Nomad47]

I haven't got to use mine much yet. But what I have noticed so far is it has always showed 0.0 after being tared. But sometimes it shows the 'negative' tare off by .02 grains, and that doesn't bother me in the least - its still the most accurate scale I own.

I have also noticed that one kernal of H4831sc appears to weigh .03 grains. So I have decided on a weight of 52.47 grains for my 6-284. And I accept a charge weight of either 52.46 or 52.48 grains. I'm NOT cutting kernals in half.

 

[Martin52]

Someone posted a suggestion that placing a ferrite core on the power cable will reduce drift - by reducing the RFI's. A ferrite core is that collar looking sleeve that you often find on eg flat screen TV power cables.

 

[bigfish28]

I look at the units display (gn) when it stops flashing the scale seems to be finished.

 

[BaconFat]

I used my GP250 last night and I ended up with a weird problem after loading 25 cases. I use the powder pan from my RCBS 10-10 and it weighs 145.24gn. I figured that instead of putting the pan on the scale and pressing the tare button, I'd just weigh the powder and pan together. That way if I had any drift I could just lift the pan off the scale and press the tare button and be ready to go again. Well over the course of loading my cases the pan's weight increased by a total of .08gn. At first it was .02gn and I didn't think too much about it. Then it jumped to .04gn and I though maybe there's was enough residue from the powder so I wiped the pan out and it went back to its original weight. Well that only lasted three or four more cases before the pan's weight had increased to .08gn.

I always double checked that when the scale was empty it read zero. My scale has been turned on for about two weeks. I did calibrate it with the 20 gram weight that came with the scale. I'm waiting for a 50 gram weight so I can do the linear calibration.

 

[savageshooter86]

linear calibrate first. Then do a normal calibration and everything should be on.

I an learning and got a lot better results of not having to tare as much the last time I used mine. I am currently using the pan it came with although it is too shallow really for weighing powder. I place pan on and tare it out. Then I am good to go. I do tare about every 5 charges anyway just to make sure.

Did you add the things to go on the AC cord to cut down on noise?

 

[BaconFat]

linear calibrate first. Then do a normal calibration and everything should be on.

I an learning and got a lot better results of not having to tare as much the last time I used mine. I am currently using the pan it came with although it is too shallow really for weighing powder. I place pan on and tare it out. Then I am good to go. I do tare about every 5 charges anyway just to make sure.

Did you add the things to go on the AC cord to cut down on noise?

I've been meaning to go by Radio Shack so I guess I'll have to go tomorrow. I'm just not very confident in the results of the GP at this point. Hopefully after jumping through all the hoops I get this thing squared away.

 

[fayettefatts]

BaconFat:

You said your scale was turned on for about two weeks. I think thats a good thing. Question is did you have the RCBS 10-10 pan on it during that time? If not, try putting the empty pan on the scale for at least a couple of hours before you start weighing powder and see if that helps.

 

[Martin52]

BaconFat,
Let us know whether you get an improvement and reduce the drift once you've been to Radio Shack and get the ferrite cable cores. If it works it will help a lot of people using the GP 250.

 

[BaconFat]

Well can you believe this. I have two Radio Shacks in the area so I call them to see if they have any ferrite chokes in stock. I don't know if they had any on-hand, but the two guys I talked to didn't have a clue what ferrite chokes were so they said they didn't have any in stock. Did go by a pretty big electronics store and they knew what ferrite chokes were but didn't carry them. Ended up ordering one from Amazon and it will be here tomorrow along with some VV N140 that I've been waiting on for a month.

 

[ronsroom1]

RadioShack® Snap-Together Ferrite Choke Core
Model:
Snap-together ferrite Choke Core
| Catalog #: 273-105

$5.59

Being a ham radio guy, I also use a Filtered Power Supply with my ChargeMaster. Keep away from florescent lighting, cell phones, computers, printers, wireless/cordless phones. They all create noise, and the scales are very susceptible to the noise they create.

Ron

 

[Nomad47]

I had the same problem at my local Radio Shack. The clerk said they didn't have any. But I found them. They were in the front right corner of a drawer which I believe was marked "chokes".

But I wish I could remember my electronics better. That type works well on either DC or AC and for the opposite you want to wrap the wire (three or four times) around one that resembles a candy life saver.

I have the clamp on variety on both my GemPro 250 and my Lyman DPS3 at each end of the power cord. However, the GemPro cord is carrying DC from the transformer (and built in rectifier) while the Lyman cord is carrying AC (the transformer is reducing the 115 VAC down to 15 VAC).