Hi, New to the forum hello all glad to be here.I'll get right to the problem. I have a fleetwood ralley year 2000 . I replaced the bottom of the magnitek 6300 series converter with a WFCO WF-8935-MBA 35 Amp Main Board Assembly.The reason I switched is because the Mag was not charging batteries and 5 of the 8 fuses had 17v on them. Now I installed the wfco and now 5 of the 8 have .06 v which is nothing. the three that work have proper 13.6v Can't figure this out. This is when pluged into 30amp service.

Check to see if one of the two reverse polarity fuses is blown. Maybe some of the utility fuses route through one and the rest through the other. Just thinking out loud.

New to RVing . Where would I look for the reverse polarity fuses.? Near the batteries?

I think at least some of the Magnetek 6300 series had a sort of internal transfer switch arrangement where certain circuits were connected to the 12V battery (presumably those that needed "clean" DC power) and others were switched between battery and converter power by a relay. This means that the DC distribution panel has two supply busses. With a more modern converter/charger, these should all just be connected together to form one bus.It sounds to me like probably your (former) switched bus isn't connected to anything anymore.

Check Bestconverter.com which has detailed writeups on how to change out your converter. Been many years since I made the conversion but I seem to recall the old magnatek had filtered and unfiltered fuses - when you make the conversion I think you change the wiring so that they are all filtered - probably illustration on Bestconverter.

I unhooked the neg battery lug plugged into 30 amp ser same problem 5 of 8 no voltage. Thanks so far from you guys. anymore ideas.

12v fuse board | Good Sam Community

DrewE
Explorer II
Apr 17, 2015
I would guess you ought to remove the green wire, or connect it to the rest of the positive bus somehow. The best would be to figure out where its other end is: it ought to just go to the converter area, and probably isn't connected to anything there, but it's certainly possible that somebody could have altered things around in who knows what ways in the past. Working on older RVs (or houses or cars or whatever) can be somewhat akin to an archeological exploration at times.

It would of course be best not to leave a live wire with the other end loose and not connected to anything.
tom68
Explorer
Apr 17, 2015
Well I'm getting 13.5 all across the fuse board. I did what you said hooked up a red jumper from that middle top eyelet over to the red positive lug.
leaving the green wire on also.
Thanks for all the great tips from you guys.
And a speicial thanks to DrewE.

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