I AM WORKING UP NEW LOADS FOR MY 375 H&H. I AM USING MY NEW LYMAN 1200 SCALE/POWDER MEASURE. I DID NOT TAKE THE TIME TO LET THE UNIT WARM AS RECCOMENDED IN THE INSTRUCTIONS.LOADED SEVERAL DIFFERENT LOADS USING RL 15. SHOOTING OVER THE CHRONOGRAPH, THE LOADS WERE ALL SHOWING ABOUT THE SAME VELOCITY. HMMM!! I FIRST THOUGHT THE CHRONO HAD A LOW BATTERY. NOPE!! WHILE GETTING READY TO LOAD ANOTHER GROUP TO TEST, READ THE INSTRUCTION BOOKLET FOR THE LYMAN 1200. IT PLAINLY STATES TO LET THE UNIT WARM UP FOR 30 MINUTES. IT REALLY DOES MAKE THAT MUCH DIFFERENCE. CHECKED POWDER MEASURED FROM THE LYMAN AGANIST A BALANCE SCALE. RIGHT ON THE MONEY NOW. I REALLY LIKE THE LYMAN 1200, BUT READ AND FOLLOW THE DIRECTIONS.

I use two of the old Lyman Autoscales that dispense the powder onto a balance beam. With these two dispensors I keep powders that I use very often and never change them, when I need that powder they are ready. I also use the Lyman DPS 1200 for many powders and loads that I place in memory and change frequently. The updated powder box makes changes in powders easy. I also use the Lyman Electronic scale with trickler for working up new loads, then program the tried and true loads into the DPS. This equipment makes my shooting a pleasure. Good shooting.

I leave my DPS 1200 2>3 on all the time at the recommendation of Lyman so there is no warm up time, it's always ready to go to work, it's been on for the last 2yrs now, works perfect!

I don't see any difference in my loads if I cancel the warm up after a couple of minutes or I leave it on for the recommended warm up time. I double check my loads on the 1200 against my RCBS 750 scale and they show .1 of a grain lighter all the time, Since I don't ever shoot max loads I am not to concerned about it.

I`ve no experiance with the Lyman, but my Pact digital will drift if I don`t let it warm up for a while before use. The scale doesn`t go far off, maybe as much as 0.5/0.7 or so grain, but it does vary.
I`ve heard others complain of the same with RCBS and other brands, so I trust it is pretty much a good idea to warm them up no matter what brand you are useing.

like the others say, just leave it plugged in and you should be good to go. Keep it away from other electrical or magnetic sources, cell phones, florecent lights, speakers, ect. They can cause problems too

It doesn't meam the 1200 will LIE to you. If the scale sez 25.4grains, then that's what you've got. What it means it that it might not throw the same weight each time you hit the go button. Yeah, them directions are some amazing things.

I had the Lyman and after the warm up it would drift, drift, drift

I have used my Lyman 1200 DPS since 2003, it has never drifted that first time. Good shooting.

Have had the 1200 Model 1 for well over 4 years-did the upgrade to the II . Usually leave it on continuously but on occasion a power fluctuation will turn it off. When I did need to use it without a 30 minute warm up all I do is do a couple of check weights to assure me it is on and off I go. Still check every 10th or 25th load for accuracy on a beam scale (1 in 10 if it is a hot load 1 in 25 for everything lesser).
Never have encountered a problem with a "cold" unit.

Gary