Gem Pro readout changing..

[PMR14]

Hi everyone,

While using my GemPro 250, I began to notice the values begin to decrease. Every few seconds causes the values to drop a few grains.

I calibrate it on "scale" with my 20gram weight. Put on a hard surface with my vibration pad underneath, center the balance bubble, move my phone and any electronic devices away and still have a decreasing value.

I have read the board, not sure why this is happening.

Thanks,

RG

 

[Powermac]

Fluorescent lights, or a ' dirty power supply can cause it.
I'd try a Ferrite (clamp on Magnetic Line Noise Filter) on the power cord.
And there are some duds arond.
Being a standard scale, at a low cost the 0.02 grain accuracy is questionable, especially when trickling as it's not a magnetic force restoration or analythical balance.
Also as with any scale, let it warm up before use.

 

[PMR14]

It's interesting that I just installed fluorescent lights above my work table.

I will check it out tonight.

RG

 

[jfseaman]

Let it 'warm up'
Clean power
Static Guard - spray your self and a little fogging of the area

 

[Powermac]

Anti static spray or cloth can help, but be very careful with the spray on the balance, unless the load cells are totally enclosed.
Anti static cloth with a bit of spray on is far safer if applied to electronics.
Applying to work area and self can help, although it's very simple getting a static discharge of your self without.

The newly installed fluorescent lights can affect it, so try and see.
As long as they're off they have zero effect.

As for the Ferrite (Magnetic clam on Line Noise Filter) i suggested at first, i know it has helped on a few of these scales, and the MX123s that has been drifting, simply due to the power grid not delivering 'clean' power, or RF noise.
Try running it on batteries only instead of the AC power supply that comes along, that will indicate if the power supply is the issue.

A few grains in drift seems very excessive though.

 

[bobke]

I'm experiencing the same drift of either tare or measured weight as well. Is there a picture of the ferrule setup you have referred to above. I can zero the tare every couple of measurements to-I think-stabilize measurements, but never absolutely certain it hasn't drifted fm tare zero to the short period actually pouring powder fm scoop.

 

[steve123]

And once again I'm reminded why I bought a Scott Parker tuned beam scale!

BTW after having 3 E scales either quit working or malfunction similar to yours I quit using them.

 

[Powermac]

I'm experiencing the same drift of either tare or measured weight as well. Is there a picture of the ferrule setup you have referred to above. I can zero the tare every couple of measurements to-I think-stabilize measurements, but never absolutely certain it hasn't drifted fm tare zero to the short period actually pouring powder fm scoop.

You must excuse my lousy technical English, calling it a Ferrule is not correct at all.
It's a Ferrite, a magnetic clamp on line noise filter, i should have explained myself better at first.
Radioshack or most other electronic store should sell these for a few dollars.
They can help eliminating drifting in your scale quite successfully and is a cheap and easy method to try, i would use one near the socket and one near the scale for optimal performance.
As i do not know exactly what causes your drifts i can not guarantee it works for you, it have for others many times though.

Here is a few links with pictures:

Noise filter (FCS-8)

Radio Noise Suppression Ferrite Filters

Would try the first one i linked or a similar as wrapping the cord around it increases the effect, not all of them are made to do that, just meausre and order one that fits on your cable diameter x 2 or so.

 

[bobke]

Thanks for the reference-will try and advise result. Really 'want' to like this scale, but it challenges me to trust it in short term of use. Fortunately, still have a couple of beams I can rely on while sorting through these issues.

 

[PMR14]

Powermac,

Thank you.

I went to a separate outlet and the calibrated the scale after warming it up for 30 mins. It helps and my readout is better. No fluorescent lights with this trial. But I will not use it right now as I still get fluctuations. This time it goes up a few grams and comes back down instead of constantly losing weight. Will try batteries to see if the power source is another source of variability.

I appreciate the input and will look into the filters. The scale was working for me before my move, so I know it was working for me in the past.

RG

 

[Twoboxer]

Powermac,

Thank you.

I went to a separate outlet and the calibrated the scale after warming it up for 30 mins. It helps and my readout is better. No fluorescent lights with this trial. But I will not use it right now as I still get fluctuations. This time it goes up a few grams and comes back down instead of constantly losing weight. Will try batteries to see if the power source is another source of variability.

I appreciate the input and will look into the filters. The scale was working for me before my move, so I know it was working for me in the past.

RG

Batteries will show the Gem this scale really is. Unfortunately, the GemPro eats batteries like candy.

If moving to another location helped, there's (IMO) an increased chance putting the ferrite cores on will improve it further.

 

[Powermac]

Glad i could help.
A warm up you should always do with digital balances, especially if there is a temperature difference if fx moving it to your bench from another room.
The fluorescent lights is best to avoid close to digital scales but the cold white 'bulbs' in them are perfect for tasks as reloading.
And it's a common headache for balances, but any electronic equipment that gives out any noise can affect it, cells, wifi, steros tv, pc etc.

Since moving the scale helped, it's very likely the Ferrites will do the trick, surely will help.
That it worked perfectly before moving is also a strong indication that it's Noise or the power source. As long as it's been transported carefully of course.
Not likely there is much difference in power quality in your different outlets, but keeping it off circuits with heavy loads, and audio equipment is advisable.

And i would certainly try it with the batteries as power source, they provide DC power and produce a constant current and voltage.
Remember your 120 V 60 hz AC is switching from +120 to -120 Volts, 60 times a second, before it's transformed to DC.
TO explain it very basically.

hope you will get the scale running reliably again, with these tweaks.


Bobke, i would certainly try it with the ferrites and battery powered.
If it does not act reliably in the end i would highly advice you to invest in something like a A&D FX 120i, another price league, but they are very reliable and accurate, also gives accurate readings while trickling, as it's a magnetic force restoration balance, at a very good price though.

 

[bobke]

I found two different size "RF chokes" at Radio Shack and am testing drift overnight. Have run on best Duracell AAA's available and will retest tomorrow. If that doesn't provide some consistency, have read other threads here recommending the 120i and it'll be either that or a Scott Parker tuned beam. Spend a significant amount of time standardizing my brass prep and loading processes, just want a return on investment in a scale for both relative speed and high accuracy. Hopeful of a result at either end of spectrum. This is starting to feel like the high quality optics 'buy once, cry once' finding after drifting through increasingly better glass over a period of time.

 

[Powermac]

A good beam balance, is always a good tool to have, as it won't stop working or dependent on electricity.
Ohaus is really the logical choice in beam balances, and will last a life time.

I surely do prefer a digital balance for reloading though, as it's easier to read, responds accurately faster, and the resolution is superior.
My Sartorius Quintrix reliably measures a single kernel of powder, every time.
It's accurate to 0.0015 grains, and gives me accurate readings in under a second even with such small variances, and i have not yet found any drifting, it costs more then i'd like to admit though.
I generally follow the buy once cry once rule for any reloading equipment, but may have a bit of OCD when it comes to this i fear.

The A&D FX 120I is about as low as i would go if you want repeatable accuracy, and fast response time, the fact it works accurately with trickling surely would be a deal breaker for me.

The GemPro is a decent product, but accurate repeatability down to 0.001 gram/0.02 grains, for 160 $ is on the optimistic side IMO , some give them great reports though.
And normally a good improvement of the more standard reloading balances.

 

[OneShotJim]

My understanding is that the recommended warm-up time for the Gem Pro 250 is 24 hours. The only times I've experienced unacceptable drift with my Gem Pro 250 were when I forgot to turn it on the day before loading. I suggest giving the 24 hour warmup a try. If the combination of (much) longer warmup and the ferrite noise filters doesn't cure the drift problem, then your unit probably needs to be repaired/replaced.

 

[PMR14]

I appreciate everyone's suggestions.

Update:
Change electrical outlet (four total), wiped the unit and my hands with a dryer sheet, used batteries, turned off all electrical noise nearby, warmed up the unit for an hour and calibrated the scale each time on "Scale".

Not going to use it, I continue to get fluctuations.

I am going to keep it on for 24 hours and see if that affects the the fluctuations, thanks OneShotJim.

Called the company where I got it from, I am probably going to return the scale and get a new one if this weekend doesn't produce any results.

Thanks everyone.

RG

 

[Break Bad]

I've used a gempro 250 for over 1,000 rounds now and I would not argue with any of the above (especially static).

But here's my experience: I usually warm it up for about 30 minutes (because I always forget). There is still a little drift..but not nearly as much. When weighing charges I make sure it reads the same thing after I lift the tray as it did before I put it on. Over the course of 100 charges I would say it drifts about .06-.1 grains...which for some people would mean 3 to 5 do-overs. For me, I really don't care if its .02 grains off. I'm still getting about 7 (+-3) SD every time I chrono.