SDBOB1 posted:I picked up an SD90 cheap unseen.Figuring make a dummy. Here the loco looks clean like new. Placed on track nothing,no lights no sound, nothing. Tried loosening truck connections nothing.For a challenge I figured try to repair. It is a 3 volt proto 2. What would be most economical way to repair? MTH parts,nos. Or ERR ?
If the goal is to make an unpowered dummy (not a motorized slave), why not simply remove the motors so the truck wheels spin freely. Or is that not what you mean by "dummy?"
Note that the "cheapest" HF meters do NOT have AC current-measuring capability. But I suppose with the "free with coupon" HF meter you could measure if AC voltage (which the cheapest HF meter has) is making it to the 7-pin connector as Joe suggests. If AC voltage is getting to the board-pair, but you do not hear the proverbial relay click-click when power is first applied to a PS2-3V board set, then you need to contact one the MTH gurus who have responded above and decide if a repair is economical.
