Or a later version! ** Your board shows surface-mounted components (vs. through-hole components on my photo) which usually comes later. Can you post a photo of the other side of the board? I wonder if you'll see another pair of those devices on the other side; for example, the MTH TIU variable channel uses such a multi-transistor design instead of a triac.
In any event, if you already ordered parts, for the record what did you get?
** Note. It appears the current version of Z controllers labeled ZCONTROLLER are universal to the 50, 75, or 100 Watt brick transformers. As opposed to earlier versions labeled Z-XXX which imply a mating to the brick of corresponding wattage. I suspect it's the earlier controllers that use the single-triac design while the later version is what you have and use an alternative design.
bbsfdl60 posted:I have seen this many times, there is a single diode on the board that needs to be replaced. The MTH part number is BB-0000057.
As for the diode, I do not see this part in my Z-750 controller so perhaps applies to the newer ZController.
The MTH site suggests the generic part number is 1.5KE51CA which is a TVS or surge-suppression diode - widely available for 50 cents or so.
