A4982SLPT compatable A4988 Driver

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Roberts_Clif
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A4982SLPT compatable A4988 Driver

Post by Roberts_Clif »

The A4982SLPT is an improved version of the A4988 stepper motor controller driver chip.
The advantage to this chip is a larger package for heat dissipation.

Note: This driver does not allow 1/8 micro stepping, 1/2, 1/4 and 1/16 only.

Now for my question.
I would like to know replacement stepper motors to use for Hictop 3DP12/12.
3DP11 - 42HD4027-01 original steppers and 42HD2037-01. 12V power supply
3DP12 - Stepper Motors only have manufactures date on them. 24V power supply

I do searches for stepper motors and get such a large variety including binoculars and Drill Motors
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GrueMaster
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Re: A4982SLPT compatable A4988 Driver

Post by GrueMaster »

You are heading into uncharted territory here. Not sure who all here is even at this level of system mods.

I found this article on how to choose. Not sure it is helpful for you. You could also search on Digikey and see if you can find one that matches the specs you are looking for.
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Roberts_Clif
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Re: A4982SLPT compatable A4988 Driver

Post by Roberts_Clif »

Should clarify My 3D Printer came stock with the A4982SLPT chip installed instead of the A4988.

Trying to find the original Stepper motors is not an easy task and those who have want way too much money for replacement steppers.
I believe have figured it all out as long as the Driver can handle the Stepper current and the stepper has adequate torque it should work.

Example a 2A stepper V-Ref = 2 * 8 * .1 = 1.6v which is pushing the chip to max output current pulses.

As Electronics Technicians/Electronics engineers know you should only operate them at ~ 80% max.
So 80% of the or the chips max drive of 2 amps is 1.6 amps. you could push this to 1.75amps being pulsed.

This says any 42mm Stepper with 1.8º 200 step bipolar stepper motor with 56mN/m torque and ~ 1.6 amps should work.
With Firmware configuration could add a .9º 400 step bipolar stepper motor with 56mN/m torque and ~ 1.6 amps.
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Roberts_Clif
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Re: A4982SLPT compatable A4988 Driver

Post by Roberts_Clif »

Doing some mathematical calculations of using known information.
I have came up with an ideal of some of the Specs for the "Date code only Steppers".

1.8º 200 steps ~900ma 5.5ohms coil resistance puts us in the neighborhood of 48~54 mN/m torque.
With this information I believe that the steppers are being under driven with only .425 V-Ref.
By my calculations .9 * 8 *.1 = V-Ref .720 will test on The Controller that already has one burnt out a4982SLPT Driver chip.

******************* SOME TESTING TIME LATTER ********************

After completing the initial setup of a spare Controller to test my theories I connected the Stepper and tested with a V-Ref Voltage of .700v
Testing with 1mm steps first then changing to 10mm steps.

I cannot believe I have been running this 3D Printer with only about 1/2 the required V-Ref voltage needed.
And it only took 1 year for it to mess up and force me to start testing to see why it was acting up an going so wrong.

Originally I used the setting that were on the controller having this 2nd 3D Printer working so well.
Did not think that the controller adjustments was incorrectly done as It was purchased used from E-Bay and work so well on every print.
Until last week when it suddenly started to print with only the Y-Axis shifting the layers...
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Re: A4982SLPT compatable A4988 Driver

Post by Roberts_Clif »

The parts will arrive soon and I can re-place the A4982SLPT Driver chips on the two controllers with bad Y-Axis drivers.

Re-moving the is the A4982SLPT Driver chip is a simple process, I will have them removed in a minute or so.
Using a method of my own design of quickly re-moving this style SMD's. Will take a dull safety razor and lightly push it threw the legs.
Being too large the safety razor will to be cut in half, in order to fit into the space available or maybe use another method chip removal.
Then remove the SMD chip package, using a soldering iron will slide the pins from the the pads and remove from the PCB.
With a vacuum pump de-solder station cleaning the excess solder is simple, simply heat while vacuuming the solder away.

My de-solder station is derived from disposed of de-soldering and Heat controller equipment.
An OK Industries DG-20 de-soldering gun connected to a Pacenter PC-10 variable heat controlled Thermo-Drive vacuum pump.
The Pacenter PC-10 vacuum pump is a little light in power to reach temperatures needed for larger de-soldering projects.
For added an power boost a 500W AC Auto Transformer 5Amp Voltage Regulator 0-148VAC will give the de-solder station this boost.

It has been quite a while since soldering this small, should not take long for this certified soldering technician to regain momentum.
Will pre-tin all the solder pads, and tack one pin on opposite corners of the SMD making sure all other legs are directly above the pads.
Lots of solder flux is needed to preform manual soldering of components this small to help prevent solder bridging.

To do soldering of small component an verify the Chip pins are in the correct locations.
I will use a lighted arm magnifying glass to see that every pin is centered above its trace and no solder bridging between pins.
Replaced the original 100W light bulb as it was too hot to work under, with a 12volt power adapter an cooler Brighter LED lighting.

My videos do not look very well though found these Video's to give you an ideal of what I will be doing, See this is simple.



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Re: A4982SLPT compatable A4988 Driver

Post by Roberts_Clif »

I removed the A4982SLPT driver Chip and replaced with a new A4982SLPT chip.

Images attached.
Removed.jpg
After.jpg
The stepper motor moves 1 step and then locks up on first controller the other no movement.
The chip went in without any complications showing I can still solder small components.
Will have to dig deeper into the circuit to see what else has been damaged.
Rs1 and Rs2 showing .1 ohm looking through the magnifying lens I see that there is heat damage to the X-Axis chip even though it still works.
The Mega2560 outputs could have sustained damage from the Power supply when it blew.

This project is going to be looked at when I get a chance to drag out the Oscilloscope.

My new 1 meg portable digital scope Kit can see the signals from the Steppers. Now just need time
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Re: A4982SLPT compatable A4988 Driver

Post by GrueMaster »

While I admire your efforts, it would be easier to just get a replacement board.
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Re: A4982SLPT compatable A4988 Driver

Post by Roberts_Clif »

GrueMaster wrote: February 4th, 2019, 9:43 am While I admire your efforts, it would be easier to just get a replacement board.
Thank You!

Though this was not just to repair the board, it is to keep my mind stimulated away from the day to day boredom.

It is to help to maintain my ability to troubleshoot electronic circuits.
An be able to replace smaller chips when necessary on more expensive circuit that are not so cheaply replaced.

Plus I had a lot of fun replacing the chips, was meticulously involved in the chips replacement.
Was enjoying myself the entire time, even bought extras at almost no cost in case replacement chip did not function.

Thought this would be just a simple replace the chip and it works.
Though I will have fun another day troubleshooting to see why it is not functioning correctly and again replace the chip if necessary.
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Re: A4982SLPT compatable A4988 Driver

Post by Roberts_Clif »

Went back to trouble shooting the controller board for a while today, Found out more is fried.

on one of the controllers the E0 Mosfet died none of the temp sensors inputs work.
On the other controller board E1 is dead, this is all added to the A4982SLPT driver chips that are gone.

Diffidently believe that are truly Dead now, no more time needs to be wasted on this project.

On a good note I have Spare Connectors of a really high quality.
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