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Fisher 400 Power Transformer

Fitzgreen505

Fitzgreen505

Member
Does anyone know what the expected voltage or impedance measurements should be for a fully functioning Fisher 400 Power transformer? I believe there are four secondaries. I haven't been able to find this spelled out anywhere. Thanks.
 
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I just take resistance measurements and if none are open or shorted they seem to be OK in my experience.

Just measured one on the bench:
Primary - black pair - 1.8 ohms
Bias - orange/brown - 1.5
Fil 1 - green/ylw - .2
Fil 2 - blue/wht - .5
HV - red/red-ylw - 5.2
 
On my 400 power transformer, I get these readings:
leads Bruce's Mine Mine as a % of Bruce's
Primary 1.8 ohms 1.5 ohms (83%)
Bias 1.5 ohms 1.2 ohms (80%)
Fil 1 0.2 ohms 0.1 ohms (50%)
Fil 2 0.5 ohms 0.3 ohms (60%)
HV 5.2 ohms 3.4 ohms (65%)


There weren't any shorts or opens, but then again, I'm not getting any power off the secondaries. (I can get power from the 120V plugs, i.e., primaries, and the power switch does work, and the fuse is ok.)

I think my readings smell fishy. Where is my power?
 
Using the Voltmeter, start at the transformer (with power on), and check voltage on both sides of each part in turn using the schematic. You got an open part somewhere, a diode, a cap, a resistor, or a combination of all 3. Insulate the probes on the meter with heatshrink tubing so that only the extreme tip is exposed. This will cut down or eliminate any shorts should you slip.

Larry
 
Just took loaded AC measurements and with 119vAC house current, getting:
bias - brown to orange: 24.5vAC:
Fil 1: 6.3v green to ylw
Fil 2: 6.4v blue to white
HV: 155.2v red to red/ylw

Sorry, don't know your experience level but have DMM set to A/C and don't measure to ground. Measure each secondary pair, e.g. brown to orange for the bias
 
Thanks for the assistance. My experience level is very low. This is very helpful.
Across the black to black leads, I measured less that 0.2 millivolts with the power on. So, no noticeable voltage is going to the transformer.
Also, just for completion sake, I tested the secondaries as well. No power coming from there, either.
Again, with the power on, I can plug in any old appliance and get sufficient power coming from the plug. I measured 120 V AC from the plugs. So, it seems to me that no power is coming into the transformer.
One last note, I also get no indications of power if I'm using a dim bulb tester or not.
 
Bummer! I had a power transformer on a Scott act like yours. I was getting good resistance readings but no voltage to one (or more) of the secondaries - can't remember now. I had Hayboer rewind a new one for me. I've seen used ones pop up on ebay or I'm pretty sure Hayboer will rewind one for you. Good luck!
 
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