I have removed the battery today, also upgraded the ROM thanks to keropi! Follow up is posted in this thread: Re: Update SC-55 ROM

I've glad that I stumbled across this thread, as it's prompted me to check my SC-55.

I bought it a few years ago from Japan and it was listed as having "no battery"

However look what I found when I just opened it up...

Thankfully it wasn't leaking, but I've removed it anyway.

I've decided to try to finally get around to fixing my SC-55, but my knowledge of electronics is limited. The issue is a blown D1 diode, listed on the parts sheet in the service manual as 1sr35-100a t-93, which is listed on it's family datasheet as a DO-41 package here:
https://www.datasheets360.com/pdf/-2147230067271245127

These seem to be unobtanium now, but in the same family with the same rating and packaging is the 1N4002A, which are very common. The 1SR35 is glass packaged while the 1N4002A appears to be round molded plastic, should they work the same way or is there a major difference that will cause problems?

Here you go:
https://www.mouser.com/ProductDetail/Diodes-I … tSXSI%252B7A%3D

That should be a suitable replacement.
Mouser has a feature that cross-references and finds modern replacement parts for some components.

so shortly after getting my beige SC-55ST which doesn't have a battery I actually found a SC-55 mkI for a reasonable price as well and I'm glad I knew of this thread, thanks.

is that white gunk on the edge?

it sure is.

I blew out the unit with some air and there was really no dust in the rest of the unit but from the battery area I saw a bit of white-ish dust being blown away, so it did already leak onto the board ever so slightly.

I'm glad I caught it in time, the board still looks perfectly fine.

the power button needs some love though 😀

DNSDies wrote:

Here you go: https://www.mouser.com/ProductDetail/Diodes-I … tSXSI%252B7A%3D […]
Show full quote

Here you go:
https://www.mouser.com/ProductDetail/Diodes-I … tSXSI%252B7A%3D

That should be a suitable replacement.
Mouser has a feature that cross-references and finds modern replacement parts for some components.

Excellent, that's the type I was looking at and ordered a batch on ebay. I've had that SC-55 collecting dust since I bought it (ebay, naturally) non working and discovered that the diode had blown. Hopefully it saved the rest of the board, but $40 years ago and another dollar on some diodes is worth taking a punt on.

Now to wait until they get here, plenty of projects to do between now and then.

I recently acquired a Roland D50 synthesizer. When I got home with it I opened it up to clean it a bit, and found a leaking CR2032 battery inside. Since I had a spare battery from the ones I bought for my SC-55 I decided to replace it right away. Much to my surprise I found out that after the battery replacement the D-50 no longer produced any sounds! 😳

It turned out that the standard patches of the D-50 are stored in battery backed up RAM memory, so after removing the battery all patches are gone! That was pretty scary, but luckily there's the internet. I downloaded the patches and was able to restore them via a midi tool. Now it works fine again! 😀

Thank you I have changed the Battery

I picked up two Roland synths over the past month - a JD-990 and M-OC1 - and those both had pretty nasty batteries. Not sure what was up at the time but I haven't had a single piece of Roland gear that DIDN'T have a totally screwed up CR2032 battery...

MarcV wrote on 2019-11-04, 11:45:

I recently acquired a Roland D50 synthesizer. When I got home with it I opened it up to clean it a bit, and found a leaking CR2032 battery inside. Since I had a spare battery from the ones I bought for my SC-55 I decided to replace it right away. Much to my surprise I found out that after the battery replacement the D-50 no longer produced any sounds! 😳

It turned out that the standard patches of the D-50 are stored in battery backed up RAM memory, so after removing the battery all patches are gone! That was pretty scary, but luckily there's the internet. I downloaded the patches and was able to restore them via a midi tool. Now it works fine again! 😀

That's actually the case for quite a lot of professional audio gear with MIDI. Just be careful if you want to do that with certain Sony units, because their factory-reset is so convoluted that reloading the patches is next to impossible.

When I got my SC-55 two weeks ago I remembered seeing this thread:

it's the thread that keeps on giving 🤣
luckily these 2032s are harmless compared to the ni-cd ones...

I did not open it yet

Thank you for this thread. I received my SC-55mkII this week and immediately checked the inside. The customs declaration explicitly stated there was no battery but there definitely was one. The white stuff was crusting around the seal. It would not have been possible to see without removing the battery from the horizontal holder. The board looked fine otherwise, thankfully.

Please, please, please check your units if you haven't yet. It looks like this is the time period where the internal batteries are just starting to self destruct and we can catch them in time. It's only five screws; rescue them.

Keropi rescuing SC-55s since 2013 😀
Anyone want to count how many were saved in this thread?

Add two of mine to the list! I have two SC-55 and one SC-50, out of the three 2 batteries had started leaking, luckily without damage 😀 I removed them all.

Thanks Keropi 😁

heheheh I never thought this thread would be still alive ! thankfully the CR2032s inside the units do not cause any damage as of now - but who knows what will happen in the next 15 years
😁

Not sure I ever mentioned this, but I found something similar in a PMA-5 unit over the summer. Bought it locally for cheap and it actually gave a low battery error when starting it up. Opened it up and found a soldered on 2032 starting to crust up inside it. Installed a holder in its place and put a fresh 2032 in there. So that is another Roland device to check as well. I wonder if there is a list of Synths and modules..etc that contain such batteries that exists so in the future we know to check or not?

I couldn't find much info on these ones besides some misinformation online, but for anyone who buys any of these: the EdiRol SD-20, SD-80, SD-90, and E-MU Proteus 2000 series all don't have internal batteries thankfully, they use flash memory. I know the P2k is pretty much just for composing since it doesn't have GM support, but the SD-80/SD-90 seem to have some fans.
The SC-8850 and SC-8820 are also clear of a battery, again it's flash memory.

SpeedySPCFan wrote on 2020-03-09, 00:26:

the EdiRol SD-20, SD-80, SD-90, and E-MU Proteus 2000 series all don't have internal batteries thankfully, they use flash memory.

Yeap, there really isn't much at all inside of the SD-20 at least. I replaced the caps in mine late last year I believe it was. And with the exception of a few games or midi files, the SD-20 has just about replaced my MT-200 in terms of using it with games.