rotel RB-9708BX-mk2 AC 120 TO 220 HOW FIX

dragonovak · 17th January 2011, 03:25 PM

Please help !

I have bay Rotel 9....mk2 it have power supply from 120 V ~60 Hz , how to connect to 220 v Please help
best regards drago

singa · 03:20 AM

Hi, For international power transformer there are 2 110 volt windings so if you want 110V Ac it is connected in parallel but I don't know what these 2 diode are doing there because normally only wire jumpers are used.Could be for polarity protection.

So if you want to use 220Vac you connect 110V coils in series.
Look at the other side of the pcb there are copper trace to the 2 110V
coils ,I think you may need to remove the two diodes and connect the
empty one at 220V but make sure it is in series to the 2 110V before
jumpering them with wire.Whether you need diode or not it's best if you can
get service manual. Ps you you are not sure find someone who knows
what to do regarding the diode. If not do not do it on your own.
Can I assume there is no switch at the back to switch to 22OVac?
Good luck.

singa · 19th January 2011, 05:17 AM

PS Before the switch to series connection (220Vac) pull power connector from main pcb and test only the transformer.If done right you will get same voltage
when wired as 110V primary at the secondary side provided you measure
110V/secondary output first to get =/- ? AC voltage. Singa

dragonovak · 19th January 2011, 02:18 PM

thx everyone i sold it

I remove the links shown and fit one in the 230 position

19th January 2011, 03:16 AM	#2
singa diyAudio Member Join Date: Apr 2004 Location: near	Hi, For international power transformer there are 2 110 volt windings so if you want 110V Ac it is connected in parallel but I don't know what these 2 diode are doing there because normally only wire jumpers are used.Could be for polarity protection. So if you want to use 220Vac you connect 110V coils in series. Look at the other side of the pcb there are copper trace to the 2 110V coils ,I think you may need to remove the two diodes and connect the empty one at 220V but make sure it is in series to the 2 110V before jumpering them with wire.Whether you need diode or not it's best if you can get service manual. Ps you you are not sure find someone who knows what to do regarding the diode. If not do not do it on your own. Can I assume there is no switch at the back to switch to 22OVac? Good luck. Last edited by singa; 19th January 2011 at 03:20 AM.

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19th January 2011, 05:17 AM	#3
singa diyAudio Member Join Date: Apr 2004 Location: near	PS Before the switch to series connection (220Vac) pull power connector from main pcb and test only the transformer.If done right you will get same voltage when wired as 110V primary at the secondary side provided you measure 110V/secondary output first to get =/- ? AC voltage. Singa

19th January 2011, 02:18 PM	#4
dragonovak diyAudio Member Join Date: Jan 2011	thx everyone i sold it I remove the links shown and fit one in the 230 position

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