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Discussion Starter #1
Hi,

We have 2 drives, one is from AC Tech "QC Series" and the other is from Square D "VSD57". Both drives have the same problem. Problem is that on power up, the display comes ON and shows the Voltage and HP Ratings of the drive, but only for a quarter of second of time, then after this time, the display goes blank (note that the backlight remains ON) (the Voltage and Power ratings shown on the display are the right ones, so there is no problem identifying the VFDs specifications).

We have done many measurements to see if there is a problem with the CPU board's power supply and the +12VDC, +24VDC and +5VDC are Ok. When the display is blank, any action on the keypad is not taken in charge by the CPU board. The drive itself doesn't work when we try to start it by using the external digital inputs. We have tried to replace the display itself but the problem is the same, so it is not a problem with the display. We have done another test, to remove the EEPROM (which contains the parameters of the drive), by doing that, on power-up the display shows Voltage and Power Ratings of the drive and stays ON. But of coarse the drive is inoperable without this EEPROM. May be the EEPROM data is corrupted or something like that.

Is anyone know about this problem?

And, I believe the problem seems to happen when the parameters of the drive are being loading by the CPU board; is there a way to perform a kind of Hardware Reset of the CPU board (parameters) (without having to go into the parameter required to do it)?

We have tried to perform a Hardware Reset by using the jumpers on the CPU board, but without sucess. May be there is a key combination on the keypad that can be done during power-up to perform the Hardware Reset?

Thanks
 

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Unless there's something extra special about these drives (are they sentimental to you, passed down from your grand-pappy?), chuck them in the recycle bin and order new ones. If they're less than 20hp, you've already wasted too much time on them. These are both way obsoleted. If they're high horsepower, just send them to Radwell like everyone else does with their old junk they want to keep running.
 

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The last time I saw this, it turns out the onboard cooling fans were gummed up with dust and pulling high control board current.
Just disconnect each fan and see if the display stays on.

Note: Most small drives have no fans and just rely on the heatsink to stay cool.
And not all drives use onboard control power for fans.
But if your drive does have them, disconnect them and see.
 

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Discussion Starter #4
The last time I saw this, it turns out the onboard cooling fans were gummed up with dust and pulling high control board current.
Just disconnect each fan and see if the display stays on.

Note: Most small drives have no fans and just rely on the heatsink to stay cool.
And not all drives use onboard control power for fans.
But if your drive does have them, disconnect them and see.
Yes, we have done this before, but the problem stays the same.
 
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