Repair ZP120

I decided to skip the dim bulb tester although I'll keep it in mind for the future. I replaced the 2 thermistors, 2 varistors and 5A fuse in the power supply section and applied power. The good news is nothing shorted out. The bad news is that some component must be open downstream because I'm not getting voltages where I should. I wish I had a schematic. It would be so easy now to trouble shoot with it. Or another good unit to compare voltages.

Piperdog, Any chance you've got any updates? I'm in the same situation.

I don't have any updates. I put my repair on hold until I can find someone who has had more time than me and who has created a schematic of at least the power supply section. Alternatively I'm keeping my eyes open for an inexpensive used ZP120 so that I can use it as a reference for the correct voltages and therefore to trouble shoot my nonworking unit..

Any new updates? I just bought a dead ZP120 on eBay and will be diving into it next week.

No updates. Keep us posted on your repair efforts.

I repaired the one I am using. It was a no power failure as well. It appeared to have some sort of liquid damage on the logic board that shorted an output of the power supply. I fixed that damage on the logic board, then started looking through the power supply. What I found was a TO-220 (or similar) package dual schottky rectifier was now shorted, also the main bridge rectifier on the front end of the power supply was also a short. Once replacing those 2, the dim-bulb went bright then dim and the indicator started flashing. And I friends was in business!
I liked the ZP120 described above so much that I just bought another ZP120 with the same fail description. I crack it open tonight. Will update this forum when I get it working.

Dose any one know where is the fuse ?

The fuse is a small orange cylindrical part by the input connector. Through hole, axial lead. I wouldn't just swap it out, it will blow again. If you comfortable around high voltage, I would try the dim bulb.

So as promised above I have repaired my new ZP120, and another 120.
The first one:
Just the input bridge rectifier has a shorted diode that blew the fuse. Once the bridge was replaced it has worked fine.

Second one:
SOmetimes it came up no led, totally dead, other times it came up and would get 1/2 way through setup before crashing my network.
Noticed a primary side 350V 33uF electrolytic cap was toast. Replaced It and nothing really changed.
This one was a real head scratcher. The blown cap belonged to what appeared to be power converter circuit that provides biases around the board. Noticed that the GND test point had no continuity to the outputs of the tapped winding. I probed a good working ZP120 and found that all of the outputs of the bias converter were grounded together. So I shorted the return of the tapped winding(8.5V and 15V outputs) to the return of the single winding (3.3V output). Was nervious to power it back up, so just in case i used the dim bulb and it worked great. Replaced the dimbulb with the fuse and I am in business.
I did a chart so my crappy memory will have some help next time i tange with a ZP100. See below.