Voltage conversion of Accuphase E-5000

@imhififan

Here are some more pictures for the auxiliary transformer: 

https://onedrive.live.com/?cid=6E164E2EDFDD40F6&id=6E164E2EDFDD40F6%2173324&parId=6E164E2EDFDD40F6%21120&o=OneUp

https://onedrive.live.com/?cid=6E164E2EDFDD40F6&id=6E164E2EDFDD40F6%2173325&parId=6E164E2EDFDD40F6%21120&o=OneUp

https://onedrive.live.com/?cid=6E164E2EDFDD40F6&id=6E164E2EDFDD40F6%2173326&parId=6E164E2EDFDD40F6%21120&o=OneUp

https://onedrive.live.com/?cid=6E164E2EDFDD40F6&id=6E164E2EDFDD40F6%2173327&parId=6E164E2EDFDD40F6%21120&o=OneUp

Thank you in advance.

in case the existing transformer is used, how should I use a resister connected in series to drop 20V?

You can use a 680Ω 3W resistor to replace fuse F1.

https://www.vishay.com/docs/28729/pr010203.pdf

@imhififan

Thank you very much for providing information. Before receiving your message, I have done modification of circuit of the auxiliary transformer. Actually, a person with electronic and soldering skill has done.

According to him,  he inserted a resister : 2000 Ohm/2.5W (10kOhm/0.5W x 5 parallel) in series to the fuse and confirmed that the voltage at the DC plus line is 20% less from the original circuitry while power SW is ON.

Do you think it is OK?

@foolishman

Although U.S. mains voltage is rated at 120VAC ± 5%, in some cases household outlets may have voltages as low as 104VAC.

My suggestion would be to power the amplifier with a variac set to 104VAC and see what the highest resistance in series is allowed to turn the amplifier on, if 2kΩ works then it's no problem.

@imhififan

Thank you very much for your quick response. I turned the amplifier on with nearly 100VAC and confirmed 2kΩ works.

I have successfully converted the E-700 from 100v to 120v thanks to your great help. Thank you very much again.

Meanwhile, also I have started discussions about voltage conversion of the E-4000 and the DP-450. I will appreciate very much if you would post information on them. I am ready to post some pictures of the power supply board.

Thank you very much in advance.