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Electronics => Repair => Topic started by: AndersJ on July 20, 2018, 11:30:01 am

Title: Rigol DP712 "Fan abnormality" message - How to clear it?
Post by: AndersJ on July 20, 2018, 11:30:01 am

The message "Fan abnormality, output disabled" is shown on the display.

The message appeared when I disconnected the fan to measure the current,
hoping to replace it with a lower noise fan.

The message persists, and the output is disabled, with the (original) fan connected and running.

How do I clear the message, and restore normal operation?

/Anders J

Title: Re: Rigol DP712 "Fan abnormality" message - How to clear it?
Post by: _Wim_ on July 20, 2018, 02:59:36 pm

Is it a three wire fan with speed feedback? If yes, could it be that the fan connector was connected incorrectly (only 2 pins connected) Did you connect the connector reversed (+ and - the other way around)?

Did you turn power completely off (iow removing the power cable)?

Title: Re: Rigol DP712 "Fan abnormality" message - How to clear it?
Post by: AndersJ on July 20, 2018, 05:44:30 pm

Two wire cable, correctly connected.
Complete turn off.

Only visible anomaly is that the fan is not physically mounted on the chassis.
I doubt that the controller can detect that.

Title: Re: Rigol DP712 "Fan abnormality" message - How to clear it?
Post by: _Wim_ on July 20, 2018, 06:22:04 pm

Quote from: AndersJ on July 20, 2018, 05:44:30 pm

Only visible anomaly is that the fan is not physically mounted on the chassis.
I doubt that the controller can detect that.

Could be the reason. The controller probably monitors the power consumption. This is the reason why sometimes an additional resistor is added to dissipate some additional power when a "silent" fan is installed..

When air flow is retricted, power consumption is higher... Try to restrict air flow with your hand and check if the problem goes away or reinstall the fan in its normal position...

Title: Re: Rigol DP712 "Fan abnormality" message - How to clear it?
Post by: AndersJ on July 20, 2018, 07:24:48 pm

Just to clarify, I’m still using the original fan.
Haven’t found a silent 70 mm fan yet.

Hand restriction did not work, or I did it incorrectly.

But,
when I put it back properly, the error message disappeared.
The speed is high for a few seconds right after turn on.
Maybe it does some form of diagnostics.

I remember thinking it took longer to rev down when the fan was out of the case.
Perhaps that was the timeout, when it gave upp looking for a proper fan?

I didn’t realize a simple chassis fan could be so sophisticated.
I need to analyze this better.

Thanks for broadening my thinking.

Title: Re: Rigol DP712 "Fan abnormality" message - How to clear it?
Post by: jmelson on July 20, 2018, 08:09:52 pm

Quote from: AndersJ on July 20, 2018, 07:24:48 pm

when I put it back properly, the error message disappeared.
The speed is high for a few seconds right after turn on.
Maybe it does some form of diagnostics.

There may be a self-heating thermistor on the main board that senses that the fan is cooling it.

Jon