[spritzer]

I thought you wanted to replace the internal transformer. External step down units are much cheaper and should have little effect on the sound if they are properly made. They can even be beneficial as they remove a lot of noise from the power lines.

 

[lyricalmoments]

Quote:

Originally Posted by spritzer /img/forum/go_quote.gif I thought you wanted to replace the internal transformer. External step down units are much cheaper and should have little effect on the sound if they are properly made. They can even be beneficial as they remove a lot of noise from the power lines.

Lemme try to get a hang on the surgery part...

Yea, any good transformer from Japan should be fine? 200w ones sufficient? Heard that some transformers have a tendency to hum, dunno if that's true..

 

[spritzer]

200w is more then enough (the amp draws 45w) and while some transformers are just badly made, hum is most often caused by noise on the AC line (DC mostly) causing the transformer to vibrate.

 

[lyricalmoments]

Ok, just got out from the operation theatre..

Opened up the SRM-717 with the ellen key, got a friend who's train in electronics and a qualified electrician to help me out.

The unit was configured for 100v. Tried to remove the top green plate, and it's glued with 3 round rubber knobs to access the PCB for the transformer. Didn't want to break anything, we unscrewed the 2 screws that holds the PCB to the chassis...now that's the tricky part, and luckily the wires are LONG enough for us to slowly pull the PCB out.

Metal jumpers were set at position 1, 3 & 6. Moved jumper 6 to position 5, removed jumper 1. (Thanks to spritzer and audiod for sharing).

Placed the PCB back, did some probes with the multi-meter... professional hazard, my friend left no stones unturned tested everything to make sure that there's no shortcircult anywhere (even the screws were not spared).

And moment of truth, plugged it into the 220v main and the power LED lights up, the red LEDs in the 717 lights up beautifully...and most importantly, no kabooms

Now can't wait for the O2 to arrive to test run the unit!

 

[spritzer]

Good to heat that it didn't have any cut windings.

 

[vitop]

I have been looking for something like this!!
Can you guys answer something for me? I just bought a 717 that is 100V and need to change it to 117V.
I saw a post by Spritzer about having to look to see if the lines are cut on the transformer and having to try and solder wires onto them. (hopefully, I can see which wires are cut when I look at it), but then I also saw that all you had to do is change some jumpers (again, I have to try and find them).
So my question is, do you have to do both (wires on transformer as well as the jumpers) or is it just one or the other.
Sorry, probably a stupid question, but if you don't ask, and don't understand, you are just asking for trouble. I can use a multi meter and I can solder and can follow directions (especially with pictures), but that's it!

 

[kevin gilmore]

you need to look at the transformer first, and fix the broken wires if they exist.
then you have to change the jumper boards.

 

[vitop]

you need to look at the transformer first, and fix the broken wires if they exist.
then you have to change the jumper boards.

Thank you Kevin -- so it's both. Now I have another question. If the wires are not there (or would they still be there but cut?) where would they connect to?
I assume that if they are still there but cut that I would still be be able to see the colors of the wires and try to connect them back up. Have you seen enough of these to know if they are normally there and connected?