@Jon G posted:90 percent of the failures in a Z-Controller is a failed TVS. You can clip one lead and see if voltage control is restored. If so, replace the TVS. A spike in voltage usually takes the out. It's the Diode shaped device bridging the two silver pads at the bottom of GunnrunnerJohn's photo.
@Roy O posted:I have had this happen 2 x and repaired them both times . Their are to plates on the backside of the board and are connected by a resistor type looking thing that connects the 2 plates. I am not a electronics repair person by any stretch of imagination I did see a photo on this forum and the item has 5KE47 CA and below it 9924E the helpful person at the electronic store found these for me. Note this is only on a Z 1000 750 and 500 are different. Yes it went full voltage and this item repaired it for me.
I'm not providing any new information, just summarizing to help the next guy who stumbles across this next year as the Z-500 thread title may be a mis-direction.
So for the Z-1000 Controller, if you get full-voltage out of the controller, disconnect (e.g., clip one lead) the diode. No soldering required to do this!
If this restores operation then replace the diode. Soldering required. Probably want to confirm the labeling on the diode. Earlier in the thread the MTH part number BB-0000057 was suggested; the MTH site identifies this as the generic 1.5KE51CA diode, widely available - 66-cents qty 1 at DigiKey. Above Roy O reports his Z-1000 controller had a 1.5KE47CA diode which is a very similar part (slightly different voltage) but also widely available - also 66 cents qty 1 at Digikey. You'll pay much more in shipping.
If disconnecting the diode does NOT restore operation, then the repair will be more challenging likely requiring replacement of one or two transistor-like devices with serious soldering involved! And that would be a good time to simply replace the diode.
