Roland Juno 106 Power Supply = bang + smoke!

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TequilaKez
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Roland Juno 106 Power Supply = bang + smoke!

Post by TequilaKez » Tue Apr 14, 2015 12:20 am

Ok so the 106 I picked up about 2 years ago was a 110V model but as I live in Australia, I thought I'd check for a 240/250V tap on the transformer before investing in expensive converters. Sure enough there was a 240V tap so I rewired it and sewed her back up and everything was great for about a year.

Then I moved house and she started f**k out. Would work for a bit and then the preset LCD would go to -- and it would lock up with no sound. I thought I'd have a poke around to look for anything obvious and checked terminals were solid and no dry solders or burns. Didn't help much but I gave it another go the other day and when I switched it on I heard a fizz, followed by a loud bang and some smoke. Caps on the PSU burst!

I'm not in a position to be sending this thing in for services costing a few hundred dollars plus a hundred postage so 'take it to a service guy' is out.

What I want to know firstly is, should I have rewired the transformer as I did? I've built some clone units and am familiar with various power transformer taps so I would have thought that was kosher.
But when I look at service manual there are apparenty 2 different PSU board numbers 76139121(120V) and 76139124(240V) . If the DC getting to the board is the same, I don't see why there would be 2 models?

Lastly, If I do indeed need the 76139124 board, where can I get it? I can only find the 120V model when I search.

Any help would be greatly appreciated. Love to get it up and running again!
(ohh, and please no 'leave it alone' replies. Let's take knowledge of saftey concerns as given :) )

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Re: Roland Juno 106 Power Supply = bang + smoke!

Post by TequilaKez » Tue Apr 14, 2015 12:51 am

Image

This is the guy. Not sure why but it has both numbers on it with no indication of wether it is one or the other. Maybe there is only one?

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Re: Roland Juno 106 Power Supply = bang + smoke!

Post by TequilaKez » Sun Sep 20, 2015 8:42 am

Ok, feeling its time to get back to this. I've been looking at the KIWI-106 board but first things first.
I can see now from the service manual that the difference between the 110/240 board configuration is just a different cap on the AC board (ECQ-U2A473MF) and some fuses instead of jumpers.

I can also see I've blown the D4 Zener, the big power caps have leaked, and C12 exploded.

Shouldn't be too hard to replace, but I don't get the cap ratings. C12 is marked 10/16 on the schematics and 0.E.44 on the cap itself. Any ideas what this relates to in farads?

And what's the purpose of C1? Do I really need to replace this for the 240V version? I can't find info on ECQ-U2A473MF, but I assume just a higher voltage rating.

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Re: Roland Juno 106 Power Supply = bang + smoke!

Post by Weirdofromouterspace » Mon Sep 21, 2015 9:37 am

TequilaKez wrote:C12 is marked 10/16 on the schematics and 0.E.44 on the cap itself. Any ideas what this relates to in farads?
Should be 10 µF / 16 V.
TequilaKez wrote:And what's the purpose of C1?
That's an AC line filter which short circuits undesired high frequencies.
TequilaKez wrote:Do I really need to replace this for the 240V version? I can't find info on ECQ-U2A473MF, but I assume just a higher voltage rating.
You need to use what is appropriate for the voltage you use. Replaceing the cap is not a big deal, so I'd just do it :).
Don't forget to TURN ON THE SYNTHESIZER. Often this is the reason why you get no sound out of it. - ARP 2600 manual, 1971

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Re: Roland Juno 106 Power Supply = bang + smoke!

Post by TequilaKez » Mon Sep 21, 2015 9:53 am

Thanks for the reply.
Ended up figuring it out with some help from the guys at the local store. They said the big caps were probably fine, just old hot glue, so replaced the diode, the AC filter and the blown cap and boom! She's alive!
Blew out all the faders while I was there and now fully working, all 6 voices and all pots caps in full working order.

Now I don't seem to be having any voice chip issues but should I be doing something now so they don't go in future?

Thanks.

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Re: Roland Juno 106 Power Supply = bang + smoke!

Post by cornutt » Wed Oct 07, 2015 10:30 pm

Alas, there is nothing you can do to preserve the 80017A's... they go when they go. How much time it spends powered up or not does not appear to make any difference.
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Re: Roland Juno 106 Power Supply = bang + smoke!

Post by sam » Sat Oct 10, 2015 1:28 pm

cornutt wrote:Alas, there is nothing you can do to preserve the 80017A's... they go when they go. How much time it spends powered up or not does not appear to make any difference.
plus the acitone trick only delays the end...if at all.
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