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8/18/2017 8:01:48 PM EDT
So, am I crazy, or is this normal?

Have gempro 250, calibrated it with the 20g weight that came with it.  no fluorescent lights in room (only led), table is sturdy, scale is level.

Put on m855A1 projectile.  62.20gn
Remove projectile. 0.00gn

cool right?

Put same exact projectile on scale.  62.1gn

o...kay....

Remove projectile. 0.35gn
Put same exact projectile on scale.  62.5gn
Remove projectile. 0.00gn
Put same exact projectile on scale.  61.75gn
Remove projectile. 2.90gn
Put same exact projectile on scale.  63.90gn

And this is all assuming I place projectile dead center on scale, standing straight up.  God forbid it lay on its side or be off center, then there are +/- 5gn differences.
8/18/2017 8:10:29 PM EDT
[#1]
Make sure you do the multi step calibration as state son in book.
8/18/2017 8:20:17 PM EDT
[#2]
calibrated again, per book instructions.

weights with same projectile, on and off.

0gn
61.60gn
-0.20gn
62.60gn
0.50gn
62.95gn
1.15gn
63.10gn
0.70gn

TARE
0.00gn
62.05gn
0.40gn

TARE
0.00gn
61.85gn
-0.25gn

TARE
0.00gn
61.75gn
0.00gn

61.60gn
-0.20gn
8/18/2017 8:20:47 PM EDT
[#3]
I tried the Gem Pro...

Saw the same type of errors...

After I returned it I knew that I couldn't go cheap on a digital scale.

I went blue...
8/18/2017 8:47:54 PM EDT
[#4]
I've not had any issues with mine. You have to be careful to follow the calibration instructions. Make sure you calibrate with nothing on the scale plate(make sure the metal piece isn't on it).
8/18/2017 8:57:38 PM EDT
[#5]
Quote History
Quoted:
I've not had any issues with mine. You have to be careful to follow the calibration instructions. Make sure you calibrate with nothing on the scale plate(make sure the metal piece isn't on it).
View Quote
recalibrated again, without the metal cover.

reweighed a projectile, without the metal cover this time.  still fucked

62.90
3.00
64.40
2.85
63.90
3.55
64.45

If yours isn't having problems, then this isnt normal and I'll send it off to the manufacturer.
8/18/2017 9:03:20 PM EDT
[#6]
Quote History
Quoted:
recalibrated again, without the metal cover.

reweighed a projectile, without the metal cover this time.  still fucked

62.90
3.00
64.40
2.85
63.90
3.55
64.45

If yours isn't having problems, then this isnt normal and I'll send it off to the manufacturer.
View Quote View All Quotes
View All Quotes
Quote History
Quoted:
Quoted:
I've not had any issues with mine. You have to be careful to follow the calibration instructions. Make sure you calibrate with nothing on the scale plate(make sure the metal piece isn't on it).
recalibrated again, without the metal cover.

reweighed a projectile, without the metal cover this time.  still fucked

62.90
3.00
64.40
2.85
63.90
3.55
64.45

If yours isn't having problems, then this isnt normal and I'll send it off to the manufacturer.
The 250 was recommended to me by some benchrest shooters. I am always very leery of new scales. I own 3 digital scales and a beam scale. My gem pro has been flawless.
8/18/2017 9:44:41 PM EDT
[#7]
Before you give up on it and send it back, try it on a different circuit or with a power conditioner. These things can be sensitive to "dirty" power, and that could potentially be caused by something that is physically nowhere near the scale.
8/18/2017 9:52:46 PM EDT
[#8]
Warmed up for how long?

Incandescent light shining directly on it (heat)?

Does the scale flutter when you put your hand near it (not the breeze, but static electricity)?

Also remove your cell phone from the area . . . and turn off/remove anything else you can think of that transmits. You may have a classic case of the flutters there.
8/18/2017 9:54:52 PM EDT
[#9]
I had a bad one and had to get it replaced. Now I have two so I can check them against each other.
8/18/2017 10:04:53 PM EDT
[#10]
Quote History
Quoted:
Warmed up for how long?

Incandescent light shining directly on it (heat)?

Does the scale flutter when you put your hand near it (not the breeze, but static electricity)?

Also remove your cell phone from the area . . . and turn off/remove anything else you can think of that transmits. You may have a classic case of the flutters there.
View Quote
warmed up for 30 min, messed with it in the first post, left it on since then (so remaining tests have been warmed up for over an hour).

leaving it on all night and will try again tomorrow.

no incandescent lights at all, only LED lights.  3x led wraparound lights on ceiling to be specific.

cell phone was in another room since the 2nd tests.  even tried putting it on battery power, and taking it to another room (bathroom 20 feet away)

I will check to see if my moving hand does anything, but previously I've had it zeroed and waved my phone around it and it didn't change.

the only thing I've noticed is that it takes forever to zero out.   i.e.  I would TARE, and it would 0.00, then a moment later go to -0.10, TARE, 0.05, rinse, repeat 10+ times til it finally stays at 0.

I don't necessarily expect it to be perfect, and minor changes are acceptable if it is as sensitive as it claims,  but a 4 grain difference on the same projectile is a bit much.
8/18/2017 10:06:22 PM EDT
[#11]
Mine works great after warmup.  If I get too quick the zero changes.
8/18/2017 10:34:58 PM EDT
[#12]
Mine did that same thing.  It happened after I moved it a little too abruptly.

I sent it in. My New one has been awesome for a year and a half.  

If it won't work tomorrow, send it in.
8/18/2017 10:45:43 PM EDT
[#13]
I had one that was having issues, sent it back the new one works great.
8/18/2017 11:12:32 PM EDT
[#14]
Sorry to say, but with this small sampling of people saying "Mine did it too, but I sent it back and the new one works fine."....  This small of a sampling, and this many people having the same issue does not bode well for their quality.
8/18/2017 11:16:52 PM EDT
[#15]
Quote History
Quoted:
Sorry to say, but with this small sampling of people saying "Mine did it too, but I sent it back and the new one works fine."....  This small of a sampling, and this many people having the same issue does not bode well for their quality.
View Quote
It's a sensitive device. I keep two now. If one breaks they will fix it under warranty.  Their aren't many scales this accurate anywhere close in price.
8/19/2017 12:18:35 AM EDT
[#16]
Any air movement in the room, including A/C vents?
8/19/2017 5:10:13 AM EDT
[#17]
Quote History
Quoted:
Any air movement in the room, including A/C vents?
View Quote
nope, basement gun room with no windows, and no vents.

thing is still playing fuck fuck games this morning.  sigh.  At least I'm not alone.

But on the plus side, after being on for 10 hours, it is really fast at coming to the wrong weight.  no more 5 second waits.  heh
8/19/2017 12:48:04 PM EDT
[#18]
Mine does the sale thing, and pushing the tare button doesn't help steady it either. I just reboot mine and check loads against it using RCBS 505 scale, seems to work. I've tried everything, leaving it on for days, no air circulation in the room, ect. I keep using it because I'm stubborn I guess, plus I'm not willing to spend a bunch more money for a better scale.
8/20/2017 12:39:42 PM EDT
[#19]
Yeah op you might just need another one. I had one and it worked great for about 1-2 months then one day I turn it on and the display lit up but the numbers didn't. So it was just blank orange.

Had to send it back and get another. My second one works pretty good but not perfect but I'm still getting by with it.
8/20/2017 10:54:35 PM EDT
[#20]
Mine is very consistent, I leave it on 24/7 and always check it or calibrate before a loading session. I just use mine to verify my Chargemaster drops but I haven't had the issues you describe.
9/5/2017 5:24:14 PM EDT
[#21]
update:   manufacturer sent a new scale and it arrived today.   plugged in, calibrated, and the thing returns perfectly to zero.  holy fuck.  it's a miracle!

tossed a m855a1 on there, 61.92gn, all 3 times I measured.   even without having it acclimated to my gunroom temperature, or being powered on for more than 20 seconds.   Definitely pleased.

thanks guys
9/5/2017 8:17:43 PM EDT
[#22]
I too had a "bad" one at first.  I don't know what the deal is with them, but my second one has been perfect.  

I like to keep mine powered so it stays "warmed up," but that's been an issue lately because of storm related power issues.  I may have a spare UPS sitting around...  And I am going to put a ferrite choke on the DC power line to avoid all those "cell phone/florescent light/whatever" issues.
9/6/2017 11:57:18 AM EDT
[#23]
Mine, 5 years old, started acting up that way a couple months ago. Could not figure out what was wrong and was just about to send it in. Then I tried replacing the batteries-- even though it always runs on AC. New batteries and it works fine again. There must be some sort of battery power thing going on even while on AC.
9/6/2017 12:46:33 PM EDT
[#24]
Quote History
Quoted:
Mine, 5 years old, started acting up that way a couple months ago. Could not figure out what was wrong and was just about to send it in. Then I tried replacing the batteries-- even though it always runs on AC. New batteries and it works fine again. There must be some sort of battery power thing going on even while on AC.
View Quote
never put batteries in the original other than to rule out "dirty a.c. power" or some other shinanigans.   same for the new onr, plugged it in and it worked fine with no batteries
9/6/2017 3:05:03 PM EDT
[#25]
Mine drifts a bit but I have my cell phone by me and a ipad on watching movies while i reload. If it drifts once, i re calibrate it. Even have a florescent light on my bench. I just block the light area that shines on the bench with thin cardboard.
9/6/2017 3:15:42 PM EDT
[#26]
Quote History
Quoted:
Mine, 5 years old, started acting up that way a couple months ago. Could not figure out what was wrong and was just about to send it in. Then I tried replacing the batteries-- even though it always runs on AC. New batteries and it works fine again. There must be some sort of battery power thing going on even while on AC.
View Quote
The failure mode (shorted battery cell) and its effect is determined by the circuitry.  As the design of the electronics is driven to be cheaper and cheaper, the design becomes vulnerable because the "normal" protection circuits are not present - sacrificed on the altar of low cost.

If you have one or more shorted cells, it can cause the power supply to operate at a very low voltage.  I suppose it could even prevent operation if it was a very low impedance short in all cells.
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