Hello. Hope someone can help me out. I have a syncrowave 350 LX (bought at auction). If its turned to A/C machine powers up just fine. If switched to either D/C +or- it makes a terrible buzzing sound and will not stay on. I am assuming it has a short in the D/C side of the machine. First guess is the rectifier. I have removed the rectifier for testing purposes. When I test the rectifier diode PN 037956 I get these results. On the diode setting (of 2 different Fluke DMM) I get .000. I get the same results no mater what ends I put the test leads on. Shouldnt I get on OL with leads in one polarity and a reading higher than .000 in the other polarity? Does this mean I have found a bad diode?YouTube is full of diode testing videos but not any diodes that look like this or this large. Thank you for any help.
Reply:The rectifier assembly has 4 SCRs and one diode. Diode D1. That is in circuit only when welder is set to DC. IN AC it is switched out. The SCRs should always read OL in both directions when isolated from each other. Diode D1 is a stud diode that is partly covered by a nomex tube. When it shorts out it causes problems like you have.But if one or more of the SCRs read 00.0 then they are shorted.With D1 isolated it should read OL and 0.4. (0.2 to 0.7). The LX welder has a vertical face and the DX welder is sloped back.The control Pcb for the LX model is obsolete. Critical parts to make the pcb are out of production.
发表于 2021-11-9 15:51:35