Repair ZP120

gruv2ths,

you wrote about a bad driver ic on the logic board, you succesfully have replaced.
just to be sure, witch card is the logic board. the one with ethernet or the one rising from the powerboard.

i have read this thread several times to figure out voltages and troubleshooting, and i think i got all the voltages right.
it sounds like i have the same problem you descibes.
it has been very interesting reading.
just need to get over the final bumb. i have to say i am noob at electronics. i am a electrician, so i hope i have a little understanding.

Hey Toden,
You probably have this fixed already, but if not the 74VLC06AD on mine was bad. You can download the datasheet and buy them from the link below. From the datasheet look at the pinouts and measure the outputs to ground and see if any are low resistance like 100 ohms or so. One of mine was, and that fixed my problem.
https://www.mouser.com/ProductDetail/Nexperia/74LVC06AD118?qs=sGAEpiMZZMutXGli8Ay4kDE4J8KCiPsFeMuB44hEVa8%3d

To anybody else, I have a repaired power board for sale on ebay. Let me know if you have trouble finding it.

@gruv2ths Ahhh you finally fixed that! How did you determine that IC was bad? Thats a tough nut to find is bad!

Hey old friend!
It was one Hail Mary after another.
I noticed that when it was failing the preamp chip was never being un-muted. I followed the mute line from the pre-amp chip up through the riser card to that driver chip on the logic card. I pulled the datasheet and found that that pin was an output and its output was stuck at 100 ohms or something like that. The other outputs on that chip were fairly high resistance. Learned a lot, many months of four letter words though. Lol

Hi guys,
Im in need of help with my zp120 ive been following this forum, built a dim bulb tester, found a short replaced the bridge rectifier and fuse, also found a small burn mark under the tranformer one of the copper wires came off so soldered it back into place, still no power, im getting no voltage on the secondary side.

Sounds like you have a open winding. Take off the transformer, you will probably see a burn mark where it came open.

Also do you see 300ish volts on one pin of the transformer and neutral on another, both on the primary side?
There is also a 100 or 10 ohm 2W-ish axel leaded resistor in series with the primary, make sure that is not open.

D16016 Cathode connects on a inner layer to the junction between C16034 and D16015. Just ohm it out, its prob fine.
That is the primary side snubber. I would also check to make sure all 3 of the diodes in that area are all ok. I have had shorts there.
Did you find something blown open on the transformer? That mark on the top side suggests an open where the pin meets the magnetic wire.