Marantz 2230 with blown transformer

EastPoint

Recycler
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Hi folks. I picked up a 2230 locally that I was told was blown up. It had an un-blown 8-amp fuse in the AC fuseholder, which was bad news. Outputs seem to test ok, amusingly enough.

I put in a normal 3A fuse and fired it up on a dim-bulb. Receiver was totally dead--no lights, no initial voltage surge at the bulb, no nothing.

Power switch is fine. I had AC at the switched outlet but nothing at the rectifier, and the transformer primary measured open line.

So, I cracked open the transformer, fished out the thermal fuse (blown), and replaced it. Now I get lights but there's still no voltage surge to light the bulb on power-up.

Primary measures about 3 ohms. I have 50.5 VAC into the rectifier (via the orange wires). I do not have any voltage across the big 4700 uf cap. Rectifier has something like 25 VDC on each side for output.

Does this mean the transformer has a bad secondary? If so, what's the likely cause, given that the outputs appear to test fine and the rectifier seems to work? Just something spilled in there or something?
 
Test the secondaries to see if they are open.
Also test continuity across the power plug blades when you push in the power switch.

Report back for the next step.

Bob
 
Power plug blades are 4.4 ohms when the switch is pushed in.

Orange wires at rectifier are 0.8 ohms.

Yellow wires at power supply are 13 ohms.

Green wires for lights are 0.3 ohms.

Power supply is putting out the full 35.6v.
 
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Your + rail to amp boards from rectifier assembly H007 should be +66.5vdc.
You can check this at J764 on each amp board referenced to chassis ground.
 
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