Technics SU-7300 Replave 110V to 220V

nuno cesar

Member
2020-01-05 12:31 am
Technics SU-7300 Replave 110V to 230V

Hello.
I have a Technics SU-7300 US version and is 110V, in very nasty condition. My goal is to practice and rebuild this amp, and if someting goes wrong i dont get very upset to blow up the amp.
But im based in Europe i can´t use it because we use 230V.
What option do i have?
Is possible to replace the transformer?
Should i get a cheap 230V to 110V converter?
For now i just opened and make a little clean.

Thanks
 

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MAAC0

Member
2010-05-02 10:00 pm
Nuno:

Nominal Voltage in Portugal is 230 / 400 V and not 220 / 380 V.

Power consumption is 140W. So you'll need at least a trafo with this power, unless You don't krank up the volume.

A motor winding workshop could count the primary windings and rewind it for 230V operation. Just double the windings.
 

nuno cesar

Member
2020-01-05 12:31 am
Hi.
I would find out why the fuses have blown but an auto transformer will be the most reliable option to power it, if the transformer is OK.
Here is the service manual; Download TECHNICS SU-7300 Service Manual
Before powering it up, check you have continuity between Black and Red, the primary of the transformer, you will know where to go from there.
A suitable auto transformer would be; RS PRO 50VA Enclosed Autotransformer, 230V ac Primary, 115V ac Secondary | RS Components


Good morning . Thank you for the tip and links. I already download the service manual.
One fuse is blow. I will get replacement soon and make more test.


Well the cleaning work is impressive!
Have you checked the existing transformer primary and secondaries are intact? If its blown you'll need a replacement transformer anyway. You can check to see if its a dual primary, 'cause that would simplify things.


Not checked yet. What you mean by dual primary transformer?


Nuno:

Nominal Voltage in Portugal is 230 / 400 V and not 220 / 380 V.

Power consumption is 140W. So you'll need at least a trafo with this power, unless You don't krank up the volume.

A motor winding workshop could count the primary windings and rewind it for 230V operation. Just double the windings.




Yes, you are right. 230V. I will need a trafo to replace the inside transformer, or an external transformer?
 

Holmer

Member
2019-04-04 4:17 pm
Unfortunately this one has a single primary (after a look at the manual).

And it looks like it is potted, and even if not, the secondaries will probably be on top of the primary. Rewinding both makes little sense. Better disconnect it, measure the voltages (on a variac or with a light bulb in series, you only need the ratios) and get a replacement.
 

nuno cesar

Member
2020-01-05 12:31 am
Good day. I decided to purchase a 230V to 110V transformer.


Is to much hassle to replace the 110V Transformer and i dont have the knowlege to do this.

to be honest i dont even know is the amp works or not.

Im still looking for a replacment of the 125V 3A glass fuse that is blew up.


Thank you all and have a nice day.
 

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