Chargemaster 1500 - no more scale drift!
- Thread starter uncle-buck
- Start date
I have of course use a McDonald’s straw trick and also tweak the settings with a video on YouTube and it is very consistent every charge gets checked on another electronic scale and they’ll most always tell me the same thing
338 Dude,
yes, i did the straw method for a while and still keep one handy. I now use a plastic insert with a tip from a Bic pen inserted into that. The Bic pen tip reduces the flow considerably and slightly increases the drop time. I also check on a second scale and usually with-in a .005 grains, then trickle to my exact weight, very rarely is it over. Since I went to this set up my ES and SD have went way down, usually in the single digits test with a Magneto Speed. The main powders I usually are using are H-4198, Varget, RL-15, and RL-33.
Lots of good info for everyone to experiment with.
Tim
I’d probably “roll my own” chargemaster into the trash can after I cross up the polarity
I need plug and playWhat do they make that is just an ac strip or whatever that I can plug my chargemasters into and my V3?
What I am currently using is a battery back up surge protector and line conditioner please excuse the dust it’s been under my reloading bench for years
Is that a ups then? What is the cost? Where does a guy get one, I looked into some and it’s apparent that not all are created equally. Some require maintenance. I’m not really worried about surges, mainly clean power.
It’s been so long I can’t be positive but with electronics I probably would’ve got it at Walmart or Office Depot $60 or so I believeNo maintenance involved
Dusty Stevens
Shiner
Youll never get clean power running on ac- no strip made can fix the power delivered to your house, they can only protect against dangerous surges. The plug and play battery pack and cable listed above run the chargemaster for a 4 day match running hard- you dont need to use that dedicated battery for anything else, even though it has a usb output to charge your phone if you like
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Further investigations find the 12V 1A recommended input is split 2 ways from the barrel jack, 12V directly to the CN4 connector then through rainbow flying leads to the dispenser unit socket for dispenser and keypad power where presumably it's regulated down for the remote keypad circuitry and dispense motor.
However that's no so much of interest as scale drift is concerned and the supply voltage requirements for the business end where the scales themselves and the electronics reside.
Back to the 12V 1A supply path from the barrel jack.....where the 2nd path feeds a small electrolytic smoothing cap or two then directly into a LM7806 voltage regulator for the main electronic brain's supply.
Some pics:
1st image, the barrel jack is clearly visible top left and the LM7806 voltage regulator just to the right.
In the 2nd image we can see the 3 pins top right of the barrel jack and top center the 3 pins of the LM7806 voltage regulator. The PCB power traces were not plain to see so they were buzzed out with a DMM.
General comments based on decades of electronics as a hobby.
The incoming supply smoothing and decoupling can only be described as minimal and arguably could be improved so to minimise power disturbances that might affect measurements although we well know from years of discussion this impacts more so on some and not others.
LM7806 required voltage above dropout is 2V so powering the CM from just 8V is quite possible.
Datasheet:
https://www.st.com/resource/en/datasheet/cd00000444.pdf
Note there is a barrel ferrite in the cabling from the strain gauge to suppress stray voltages from impacting on measurement stability.
In closing, I do not advise owners to open there CM scale module as parts like the strain gauge are very delicate as are some cables and the cabling connection layout is not conducive to simple dismantling or reassembly when in fact it's a bit of an awkward SOB !
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