Hi Chuck,
typical symptoms of a speed control pot/switch on its way out, the change of the feedback is causing the jumps in speed all over.
I had exactly this with my lathe (same design as mill) and it started gradually intermittently with slight jumps becoming more frequent and worse as time went on.
A quick clean of the pot with switch cleaner spray may eliminate it for a short time but is only a temporary solution so replace the combined pot/switch as soon as you can.
The part is cheap and widely available and a fairly simple soldering job to replace and should cure your problem as it did mine.
Gerry
Leeds UK
To: GrizHFMinimill@yahoogroups.com
From: chunk07@comcast.net
Date: Sun, 4 Sep 2011 14:35:57 +0000
Subject: [GrizHFMinimill] Re: Mill controller woes
--- In GrizHFMinimill@yahoogroups.com, "chucketn" <chunk07@...> wrote:
>
> My X2 mill has started playing up again. First it started acting like the motor was cutting out during a cut. I checked all connections again. I even replaced the brushes. Now, under load or not the speed randomly jumps up to roughly twice the set speed. I can't afford to replace the controller now. Help! Is this the symptom of a fet going bad? I do believe I have some spares.
>
> Chuck in E. TN
>
More symptoms. Now the speed control pot/switch is intermittent. I can turn it off and the motor continues to run. Sometimes turning it of and on by the speed pot/switch has no effect and it runs at full speed.
Time to re-read the troubleshooting files again...
Chuck in E. TN
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typical symptoms of a speed control pot/switch on its way out, the change of the feedback is causing the jumps in speed all over.
I had exactly this with my lathe (same design as mill) and it started gradually intermittently with slight jumps becoming more frequent and worse as time went on.
A quick clean of the pot with switch cleaner spray may eliminate it for a short time but is only a temporary solution so replace the combined pot/switch as soon as you can.
The part is cheap and widely available and a fairly simple soldering job to replace and should cure your problem as it did mine.
Gerry
Leeds UK
To: GrizHFMinimill@yahoogroups.com
From: chunk07@comcast.net
Date: Sun, 4 Sep 2011 14:35:57 +0000
Subject: [GrizHFMinimill] Re: Mill controller woes
--- In GrizHFMinimill@yahoogroups.com, "chucketn" <chunk07@...> wrote:
>
> My X2 mill has started playing up again. First it started acting like the motor was cutting out during a cut. I checked all connections again. I even replaced the brushes. Now, under load or not the speed randomly jumps up to roughly twice the set speed. I can't afford to replace the controller now. Help! Is this the symptom of a fet going bad? I do believe I have some spares.
>
> Chuck in E. TN
>
More symptoms. Now the speed control pot/switch is intermittent. I can turn it off and the motor continues to run. Sometimes turning it of and on by the speed pot/switch has no effect and it runs at full speed.
Time to re-read the troubleshooting files again...
Chuck in E. TN
__._,_.___
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