Digital Scale Woes

S

SGJennings

New member
I have an RCBS RangeMaster 750. It's always drifted, but it has been manageable.

Last night and tonight, it has gone completely batty. Sitting there with just the pan on it, it's drifting up 1.5 grains or more and then back down. In just a few minutes.

Something else weird I noticed is that when I put my hand near the top where the pan sits, the scale goes bonkers. It's like I'm full of static. I haven't had static shocks, but I grounded myself anyway...no difference.

Looks like someone is about to get a rush order on a scale...

Greg J.
 
my only use for digital

i only use digital scales to weigh a new batch of brass because of the zeroing function. i can place a piece of brass on the scale and zero it out. from that reference point it will show any deviation plus or minus in .01grain increments to sort brass by weight.
for reloading cartridges i use an RCBS 10/10 avoir dupis scale exclusively.

Fred
 
I ordered a ChargeMaster. There is a fellow that tunes up the balance scales. I'm going to find his info and order one as a backup.

The way my RCBS 750 is behaving is just ridiculous.

Did I mention that I have it on a slab, traded the fluorescent lights for incandescent, am running it off an uninterruptable power supply and it's under a draft hood?

I'm torqued!
 
In recent years, RCBS, has had digital scales made by both Pact and Ohaus. Many of the PACT made scales are cheap and troublesome. I know, I have several. You get what you pay for. For example, the now obsolete RCBS Model 90, made by Ohaus, sold for over $400. All of these RCBS/Pact scales I have cost $100 or less. The two Chargemasters I have were made by Ohaus.


I can't speak for the model 750 since I don't have one. IMO any digital scale, like any device that uses digital/analog (DA) technology can get screwy.
 
Greetings. I too have an RCBS 750 and it does tend to drift after a while. A couple things. I'm sure you're aware of these but I'll mention them anyway-

You've turned it on and let it "Warm up" and stabilize for 15 or 20 minutes prior to use?

After warm up you calibrated (Using check weights) & zeroed ?

You have no electrical/electronic items in the area, i.e.- Cordless phone, cell phone, wireless computer in use, radio, etc.?

I was using mine and my son came around to observe and the scale started going bonkers. Took me a minute or two to think it through and ask my son if he had his cell phone on him. Answer was yes and that's what was causing the abnormalities.

Cheers,

Mark
 
> You've turned it on and let it "Warm up" and stabilize for 15 or 20 minutes prior to use?

Oh, yes, I never turn the scales off. They were warm. I also calibrated and zeroed.

> You have no electrical/electronic items in the area, i.e.- Cordless phone, cell phone, wireless computer in use, radio, etc.?

No cell phone. We have cordless phones, but they were in the docks i.e., off and some distance away. We do have a wireless network. It is also some distance away. I guess I could try turning it off. I am running the scales off an uninterruptable power supply so there are no currency fluctuations. I guess I could take it off of it and turn it off.

After I check the stuff above, I'll check into what RCBS will do for me on it.

Does anyone have any idea why it will move 1.5 gr when I get my hand close to it? I mean, it's not like I have a magnetic personality....
 
Sounds like your body may have static electricity, which is more common in the winter months. Try rubbing you hands with a clothes dryer tear sheet and same with the scale. You may even place the tear sheet beside the scales when in use. Seems this is a common problem with many digital scales.
 
I have the 750 without problems, as others have posted electronics will cause problems also fan or vents,vibration, I warm mine approx. 5 minutes, calibrate use the next hour and check calibration again needed or not, I find the scale very accurate and fast, I back up with a Lyman balance beam scale and on occasion check one against the other.
 
I *absolutely* do not have a wind current problem. It's inside a cover I made.

Tonight, I took it off the UPS, unplugged everything in sight including the cordless phones and turned off the wireless router.

It is always on, so there is no warming up. I calibrated every 10 cases.

I returned the pan to the scale every time.

I noticed no drift in the weight of the pan (zeroed to that).

I did notice 0.2 gr drift with the pan off and 0.2 grains drift in the weight of the 20 gram calibration weight.

I don't remember if it was the case before, but it only does the "magnetic personality" drift when the pan is off the scale top. It's over 1.5 grains. It's not drifting when the pan is on. So, I guess I need to not let this bother me.

I'm definitely going to try the dryer sheet. I've used them in the past to prevent static cling of powder.

Greg J.
 
maybe

Air from your ac vent,even though not detectable, is enough to vary my beam scale nearly a grain.lynn
 
It is always on, so there is no warming up. I calibrated every 10 cases.
Click to expand...


I may have misunderstood but do scale remain on 24 hours per day?, if so
that in its self would be a bad idea, after use I shut down and seal in plastic
container.
 
oldguy said:
I may have misunderstood but do scale remain on 24 hours per day?, if so
that in its self would be a bad idea, after use I shut down and seal in plastic
container.
Click to expand...

Why is it a bad idea to leave it on all the time? I work in the electronics industry and as a rule, things work best when left on all the time as they are stabilized. Just curious why you would make a statement like that.
 
SGJennings,
What was your draft shield made of?
Plastics can hold a static charge. I ran into this with a wind box for a 10-10. It moved the reading .1 gr. With glass, no problem.
 
oldguy said:
I may have misunderstood but do scale remain on 24 hours per day?, if so
that in its self would be a bad idea, after use I shut down and seal in plastic
container.
Click to expand...
I worked in an analytical lab during college. We had the highest precision instrumentation available. The scales stayed on, as far as I know, the entire 4 years I worked there.
 
It's made out of foam board. I have no idea if it'll hold a charge or not. It's entirely possible. At any rate, I didn't see nearly the drift after I tried to address EMR.
 
I worked in an analytical lab during college. We had the highest precision instrumentation available.
Click to expand...


Not to be argumentative however I worked in a lab 12 years our scales also remained on however they cost much more, but to each his own.
 
Back when i actually worked for living we left all the electronic scales and balances on ALL the time which is what Mettler and Sartorius recommended. Those scales and balances would drift over time, and they were top of the line products at the time (10-20 years ago). A certqin amount of drift is going to occur with electronic balances and scales in my experience.

If they're damped enough to not drift they'll likely respond so slowly that you'd never get anything done.

My Chargemaster 1500 will drift a bit in use, but just sitting on the bench nearly always reads 0.0 when not in use. It's always on unless there's a power outage or I'm gone for a while.
 
This topic seems to come up

about every year at this time. A couple of years ago someone suggested sitting one's scales on a grounded black rubber mat which are made for Keyboards and such. I use to have the link for a place to buy them but never got around to it.
 
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