I just checked my multimeter/probe on a laptop PS. For 19.27v it got 0.019v. I last checked it with a different multimeter. This one is much cheaper but seems OK but claims 750v max.
kffern
kffern
kffern -
how did the swap go? In my experience, the MOV's are the source of imbalance in those circuits if it's not grossly different. If one is really off, it's a bad diode. Rare, but possible are the caps, and I've seen corroded traces on the long curvy ones that connect the first group of 4 diodes to the second.
Sheldon
how did the swap go? In my experience, the MOV's are the source of imbalance in those circuits if it's not grossly different. If one is really off, it's a bad diode. Rare, but possible are the caps, and I've seen corroded traces on the long curvy ones that connect the first group of 4 diodes to the second.
Sheldon
The swap went well. It seems to have solved the balance problem. They are now close to perfect. Sweeps of left and right speakers nearly overlay.
it was probably a bad solder joint somewhere. I will source the parts to eventually replace them. What EHT voltage should I expect from this board? How come they are not in the Quad service manual?
I found your board plans on Oshpark. Maybe I should start fresh or find a spare board.
kffern
it was probably a bad solder joint somewhere. I will source the parts to eventually replace them. What EHT voltage should I expect from this board? How come they are not in the Quad service manual?
I found your board plans on Oshpark. Maybe I should start fresh or find a spare board.
kffern
I wouldn't start over with new boards unless the traces are lifting/bad or it is badly damaged. Yours seem like neither, so I'd stick with them. Note that the ground reference is through a mounting screw to the input chassis-work. If that connection was bad/ loose, you might not have been getting the full polarizing voltage. I've never seen that happen, but that doesn't mean it doesn't. That board should be in the 5.25kv range.
Sheldon
Sheldon
You aren't kidding. I just checked DigiKey and the lead time for the quad OEM part: GP02-30-E3/54 is July....of 2023!
RS supplies has them or did yesterday. Epay scoundrels are selling them for 4 or 5 times the price.
I have been looking for Vishay MKP 220uf as an economic and practical alternative to C25. Its listed on Mouser but only in bulk with a long wait time. Found them on https://quadesl.nl/product-categorie/esl63/ but they have never sold anything outside of EU. He was very polite but looks like it isn't worth their time. Dada electronics from Holland doesn't seem to have a problem and I have made a couple of purchases.
So much for Globalisation!
kffern
I just got delivered these. They have more if anyone is looking. I assume they are suitable.
kffern
Vishay 3000V 250mA, Silicon Junction Diode, 2-Pin DO-204AL GP02-30-E3/54
I will get the rest from ER audio.kffern