# AC tech blank screen



## JRaef (Mar 23, 2009)

It's been a while since I worked on one, but I seem to remember that they don't use a separate AC power supply board, they tap off of the DC bus. That just means it's a DC-DC power supply, just so you know. 

Did you double check the cables connecting the display? If it wiggles loose, the display dies and that drive can't run without the display.


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## Cow (Jan 16, 2008)

Everytime I deal with an ACTech, I can't wait for the day it dies so I can replace it with something that's not a turd.


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## Handasee (Dec 18, 2009)

JRaef said:


> It's been a while since I worked on one, but I seem to remember that they don't use a separate AC power supply board, they tap off of the DC bus. That just means it's a DC-DC power supply, just so you know.
> 
> Did you double check the cables connecting the display? If it wiggles loose, the display dies and that drive can't run without the display.


Display cable is properly connected.
I want to find out what part failed so I can figure out why it happened.


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## JRaef (Mar 23, 2009)

> Blank Display
> or repeatedly
> flashes
> TESTING
> ...


They don't give out information on components inside of the drive.


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## Handasee (Dec 18, 2009)

JRaef said:


> They don't give out information on components inside of the drive.


I read the same info in the manual, but I'm sure other people have gathered more information.


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## JRaef (Mar 23, 2009)

Generally, the only people who get service and repair schematics are companies that do that kind of work and can afford the "entry fee", such as electronics repair firms like Electrical South or EMA. They must pay a license fee for access to the drawings and sign a waiver saying they will not use them for designing a competing product. Lenze (the German company who now owns AC Tech) wanted a $1,500 licensing fee plus $50 for a schematic on one of their 9300 Series drives I was trying to repair once. I just junked the drive...


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## John Valdes (May 17, 2007)

If the control board is shot, its not worth repairing. I bet its the control board.
In fact, any time spent trying to fix this throw away control would be time wasted.

Unless you just want to work on it, I would order another one. You could actually work on this bad one while the new one runs the application.


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## Handasee (Dec 18, 2009)

John Valdes said:


> If the control board is shot, its not worth repairing. I bet its the control board.
> In fact, any time spent trying to fix this throw away control would be time wasted.
> 
> Unless you just want to work on it, I would order another one. You could actually work on this bad one while the new one runs the application.


A new drive is on order. 
You are right, that it's easier to just put in a new drive, but I want to know why it went. Replacing anything without knowing what caused the problem is asking for trouble. If I put in a second drive will it blow? Application is very simple. VFD is for an auger moving plastic pellets. Operator turns on a master control switch that gives power to a contactor, through a reactor to the VFD (3 phase 575V input). Control is a 3 wire start/stop and speed via a potentiometer.
Machine was modified with a new auger last month and relocated to a new place in the plant. Load did not change from previous auger. 
So is it just age, Operator error, power problem? 

I will work on it just for my own knowledge.


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## JPC.CE (Jul 20, 2015)

AC Tech oh boy, I now have 8 of these little curses in my mill, as soon as they pop they are out of here. Pain in the butt, 
Cheep, poorly put together, software is not user friendly after the fact. mill owner wanted to try them.... Noting but lost time.


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