Accuphase E-480

@imhififan 
Thank you!!

Here's the jumper setting changed for 120v:

J4 -> J5

J10 -> J8

J6 -> J11

Thank you again.

I can confirm that the above jumper configuration results in the orange & yellow taps @ 120V, thanks @imhififan 

One thing I was a little bit surprised by was that some of the rails to the power amp board were raised by a few volts (like 65VDC to 69VDC) when compared with the 100V step down. That being said, the test points for +-5V, 12V, 15V tested correctly. The +130V was previously around 135VDC and is now 139VDC. I see one trim pot on each amp board, but not sure if that's for DC offset or bias. Do these units have a self-biasing circuit, I wonder?

That being said, the 5V supply to the IC's remained at just under 5VDC, so I think all is well. There was no impact on the DC offset, and the unit appears to sound the same as before, and the heat output appears similar as well.

My AC mains are 122VAC rather than 120, while the stepdown is at exactly 100V -- maybe that's part of explanation of the increase of a few volts? I'd imagine the regulators would clean it up anyhow, right.

Congrats! @sp33ls2

One thing I was a little bit surprised by was that some of the rails to the power amp board were raised by a few volts (like 65VDC to 69VDC) when compared with the 100V step down... My AC mains are 122VAC rather than 120, while the stepdown is at exactly 100V -- maybe that's part of explanation of the increase of a few volts?

Yes, that's the reason and nothing to worry about.

I see one trim pot on each amp board, but not sure if that's for DC offset or bias. Do these units have a self-biasing circuit, I wonder?

Most new design Accuphase power amp has no dc offset adj pot. I believe the trim pot is for bias adjustment and the +/- test point should has a reading of 4mV, but I not 100% sure since I don't have a service manual on hand, perhaps you can measure it to confirm.

I believe the trim pot is for bias adjustment and the +/- test point should has a reading of 4mV...

Correction:

I believe the trim pot is for bias adjustment and the +/- test point should has a reading of mV, perhaps you should measure and recorded it for future reference.