AMI F-120

[b***@yahoo.com]

Just bought this ami f-120. ac side is okay. seems as though I don't have any control power. took the junction box off after I checked the fuses. there is a black lead and a yellow lead hooked to the rectifier. When I put my black lead to the black wire and red lead from the meter to the yellow wire I get 76 volts. when I put the red wire on the 8/10 fuse holders it shows momemtarially 16 volts then immeditally goes to -1. same on both sides of holder. am I testing it right and if so does it mean my rectifier is bad. its still the same old rectifier it came out with. thanks for any help. norm

[c***@yahoo.com]

Norm, here is the schematic for the F. As you can see, the output from the transformer goes right to a bridge rect. The output should be approx 28 volts Dc

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Check to be sure you are using the correct common point for ground return on your meter and correct scale. It looks like the low-Dc supply floats above chassis ( I may be missing the tie point) so measure across the rect out (DC) terminals.

It is a good idea to replace these old selenium units. A new silicon bridge will sag less and help speed up the old motors. I used typical 25amp 100volt (or more) bridge packages.

Rob-NYC

[b***@yahoo.com]

Post by b***@yahoo.com
Just bought this ami f-120. ac side is okay. seems as though I don't have any control power. took the junction box off after I checked the fuses. there is a black lead and a yellow lead hooked to the rectifier. When I put my black lead to the black wire and red lead from the meter to the yellow wire I get 76 volts. when I put the red wire on the 8/10 fuse holders it shows momemtarially 16 volts then immeditally goes to -1. same on both sides of holder. am I testing it right and if so does it mean my rectifier is bad. its still the same old rectifier it came out with. thanks for any help. norm

thanks rob. I have a print for it. going to order a rectifier for it. just not sure where the wires goes. I think I know but not positive. thanks norm