Shane711
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Re: Repairing WFCO 8955 converter and closely related models
Well, I figured out the mistake I was making and now I got these converters working. And to comment on DSteiner51's post, I believe that all the converters are bad even the new ones because in my experience they are all designed to fail. But after I fix them they will not fail from age as before. The way these are built they will only last for 2 to 3 years if you use them a lot. After I fix them they should last for 20 years no matter how much you use them.613Views0likes0CommentsRe: Repairing WFCO 8955 converter and closely related models
I offer a repair service on eBay for these converters. I may have to take down the listing for the converters with the daughter board until I figure out the problem with the KA3846 IC. I have basically told everyone on this forum my secrets to fixing these. ;) But I am OK with sharing the knowledge and I may not be doing it come next year. Once I figure out this IC I will have it mastered. I decided to start repairing these when I realized how easy it was.613Views0likes0CommentsRe: Repairing WFCO 8955 converter and closely related models
OK, I see that in the link you provided but it looks like it is suppose to reset itself. If not I have to figure out how to turn it back on. Also it says "• Programmable Pulse by Pulse Current Limiting" and this has me thinking, do I have to program the IC before I can use it?614Views0likes0CommentsRe: Repairing WFCO 8955 converter and closely related models
I don't know how to pm him, I tried but no luck. He is either not on this forum, I don't know his user name, or he is not excepting pm's. I am not sure but I can't seem to do it. He may have the missing info I need to figure out that KA3846 IC613Views0likes0CommentsRe: Repairing WFCO 8955 converter and closely related models
Thank you, those comments are much appreciated. I do plan to fix the issue with replacing the KA3846 IC but help would be nice. Someone out there must know what I am doing wrong. I heard there was a way to reset these and then I read something about forcing them into boost mode. There was this guy who had connected switches to it so he can put it into boost mode or take it out of boost mode. If I understand it right, regular mode is at 13.6 volts and boost mode is over 14 volts, like 14.4 maybe. But I have not got that far with these yet. This is the post I found saying all that stuff ~~> https://forums.goodsamclub.com/index.cfm/fuseaction/thread/tid/24492263/print/true.cfm Wayne Dohnal started that post, if anyone knows who he is I think his comments would be of a great value to this discussion.614Views0likes0CommentsRepairing WFCO 8955 converter and closely related models
So I repaired a couple of these converters and I want to share my knowledge and I am also hoping someone with a little more understanding of these will join the discussion. There is 2 types I know of. Type 1 does not have a daughter board. Type 2 does have the daughter board. If your converter is not blowing the fuse and your voltage is from 2 to 7 volts then you are in luck, it is an easy fix. Those 2 rectangle white ceramic resistors is the cause of ALL your problems. They get so hot that everything around them burns up. So change all the small capacitors near the 2 white resistors. If you have type 1 then you just need to change 1 capacitor, but when you put the new one in, place it on the underside of the board to keep it away from the heat. If you have type 2 with the daughter board then you will have 2 or 3 capacitors to change, the 3 small capacitors closest to the white ceramic resistors. Because the KA3846 IC chip is located near the heat it may also blow. If it does blow it could literally explode your mosfets. So if your Mosfets or large diodes are blown you need to suspect the KA3846 IC. This is where I need help from some with more knowledge of these. After replacing the KA3846 IC the unit does not work, 0.00 volts. So I could use some help. If you reversed your polarity or crossed the wires you blew it up; but not to worry, it can still be fixed. First thing is to check the underside for broken solder connections or burn marks, those parts should be replaced. Check your mosfets and large diodes on the large heat sink to make sure they did not blow. Next is to check and replace the fuse. After that just go over the board and test whatever your skills will allow. If all is good you may have fixed it. There is a big green wafer thing that usually blows up, it protects the unit against surges, if yours is about 3/4 wide it may be a 2R515 but if it is an inch or bigger then it may be a 251R0. I also have done upgrades to some of mine. I have added heat sinks to the BIG ceramic resistors and small fans that turn on using thermal switches. So anything about fixing these, upgrading them, or modifying them. I am interested in what we can all learn. ALL these units will fail from the heat of those ceramic resistors. I got a heat shield on all of mine that have the daughter board, and when possible I reinstall the capacitor on the underside of the board. :)5.2KViews0likes15Comments
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