Bose Companion 3: Repair and voltage conversion from 220V to 110V

[powerslave]

Folks , I have an old Bose Companion 3 which I had brought back from the USA years ago, my family plugged it into supply without a step down transformer and it went dead. It was told to me there was no smoke or pop. So I opened it up based on some google search pages that claim one can convert this into 220 V as the board is common across the units for different regions.

I don't see any burn marks or spots on the board (Bose has made it hard for people to repair things) ; the terminals to which fuse is soldered clearly specifies ratings for 110V and 220V fuse variants. So it tells me that this is a common board for all regions. However I wanted to know if someone has done this before or can confirm if my understanding is correct ?

 

[ShantaramChari]

Folks , I have an old Bose Companion 3 which I had brought back from the USA years ago, my family plugged it into supply without a step down transformer and it went dead. It was told to me there was no smoke or pop. So I opened it up based on some google search pages that claim one can convert this into 220 V as the board is common across the units for different regions.

I don't see any burn marks or spots on the board (Bose has made it hard for people to repair things) ; the terminals to which fuse is soldered clearly specifies ratings for 110V and 220V fuse variants. So it tells me that this is a common board for all regions. However I wanted to know if someone has done this before or can confirm if my understanding is correct ?


View attachment 57014

Sir, I have repaired the same. While it was one my uncles speaker. You can go to your nearby transformer repairing shop and tell them to make primary winding of 220v and the secondary winding as per the original. By replacing this you can retrieve you bose companion back to work

 

[powerslave]

So you changed the torroidal transformer inside ? In that case perhaps just replacing with same fuse and using a step down trafo might be a better idea.

 

[manniraj]

I do not think fuse is the same, please check as I can see from the pic that the 220-240v primary needs a fuse of 1.6A whereas usually 100-120v primary needs double that that 3.1A. Get the similar rated secondary winding but do make sure when you remove the transformer check if on the AC side any part is burnt up using magnifying glass and good lighting.

 

[log21]

There would be a varistor . check if that has blown . It usually is a circular disc . Try to find a 500v -1000v one to replace .

Edit:
Just saw the pic again . it says VR1 . check that . searched on google part no . 275L40B

 

[drlowmu]

What if you someone blew one or more devices in the amplifier, due to a momentary application of double the VAC / VDC ??

Rather than replace the Power XFR, at a certain cost, only to find other things ( after the power transformer, in the circuit ) are damaged beyond easy repair, why not this :

Replace blown fuse. Slowly start unit up on a VARIAC, carefully monitoring the amplifier with a DMM. See if all measures OK up to 120 VAC of line input from the Varaic.

Pay attention to Varistor, if necessary.

If unit measures normal on a 120 VAC variac line feed, ( no voltage offsets on the output / speaker connections) you should next, determine if it passes a signal.

Only then - consider the expense and need of a different Power Transformer for 220 VAC operation.

 

[AKT]

Same problem with my wave music system. I was suggested exactly what Shantaram mentioned. I just got it repaired as 110v and use it with a step down. did not want to touch the transformer. Anil PV in Sarjapur fixed it for me.

 

[powerslave]

^ Thanks man, will try it out . I was trying to pull a DIY here

 

[nikhilblr]

Same problem with my wave music system. I was suggested exactly what Shantaram mentioned. I just got it repaired as 110v and use it with a step down. did not want to touch the transformer. Anil PV in Sarjapur fixed it for me.

Does Anil also fix audio equipment like cassette decks and if yes can you please share his contact details?

 

[drlowmu]

^ Thanks man, will try it out . I was trying to pull a DIY here

You may not even have to replace the Power Transformer. It may be designed and configured as a dual primary winding XFR, in which case, you would unparallel the two 115 VAC windings, and IN PHASE, connect the wires to produce 230 VAC in a series connection. Did you know, E.E. Amar Bose .................became a billionaire !!