SH-101 Mains Hum

[gowans]

I just spoke to my mam she thinks Harry maybe my grandads cousin. My grandad is called Tom Oliver. Definitely right Oliver's as they told me some Oliver's lived in Wesley way!

[lem]

i have never read anything so OT...
...interesting tho. like eastenders with analogue synths...

[steevio]

haha so weird,

my dad is called tom oliver, but obviously not the same one, i asked him and he said that he used to sit next to a boy also called Tom Oliver at school who he wasnt directly related too.

all the Olivers are related anyway as they were a border reiver clan, there's actually a small town called Oliver in the Scottish borders where we all come from originally.

we might be related, or your grandad sat next to my dad at school haha

how old is your grandad ? my dad is 86

hows the SH101 ?

[agodi]

Did you manage to sort out your 101?
Theres a guy in Dublin who repairs synths but also blogs about some of the repair jobs hes done and common issue he sees. You could try emailing him to see whether he can identify where your problem might be. http://www.retroactivesynth.com

Heres what hes lists as common 101 issues

Due to the external Wall-Wart many of these have damaged internal power supplies due to incorrect external power supplies. Badly corroded battery terminals are also quite common (even alkalines will corrode eventually).
The most common serious problem is the demise of the Curtis CEM3340 oscillator chip, the symptoms are obvious, the synth makes no sound apart from the noise generator. The CEM3340 is becoming a rarer and rarer chip these days, as so many synths worldwide used it and it has been out of production since the mid 80's. Expect to pay €50 these days just to get hold of one of these chips.
Other issues are worn out sliders and dodgy keyboard contacts.
Despite the above, the SH101 is a very reliable synth, it is well built, sounds very good and the far east yet again can supply a lot of the otherwise unobtainable spares.

Normally a Roland SH101 should hold no major fears for a synth tech, there are several quite common faults with these, the blown power supply, the dead Curtiss oscillator chip, the odd Op-Amp failure in the LFO or elsewhere, but nothing that will tax the competent soldering iron wielder.

[gowans]

been a while since ive been on here, busy with work n that, havent even had a chance to properly have a look at the synth. the source of the problem is definitely the lfo, when the red light blinks the whine noise drops or raises in pitch, its always there in the background. im gonna run out today i think and grab a new PSU see if that sorts it out. also worth noting that the battery compartment doesnt work at all. rest of the synth is in mint nick, looks like it just came out the factory. i dont fancy sending my synth off to dublin or anything just local would do me, i dont really wanna send it anywhere tbh!

[AK]

The springs seem okay, I'll check it with another set of batteries. These batteries don't come cheap! I spent £10 at tescos for 3 packs of these C Size duracells!!

Mate, go to Poundland. I have a 101 and it came with a noisy PSU, I sent off for the Boss one and while it's on its way, I'm using Sony batteires from Poundland. A 3 pack for a quid, I got 12. By the way, that was the very first thing I checked when I got my 101, I heard a bit of noise/crackle/hum and tested it with batteries immediately and it was as quiet as a mouse.

I doubt you have faulty batteries though as they're supposed to be QC tested so maybe try them in something else before getting some more.

[gowans]

yeah good idea mate i'll go there next time, ive tried again with the batteries still no joy, wont power up, works fine from mains, whining noise is still there. ive opened the 101 up to check the connections to the battery compartment and they seem okay, its baffling me why the batteries wont work. im waiting on the photos ive took from my phone to come through on email then will post. there's a blue wire that comes from one of the battery connections that goes behind the board that i cant see but ive felt with my finger and it seems connected properly.

[AK]

Have you got anything else you can check the batteries in? You could test em with the old wire and xmas tree fuse light trick....

Did I read you're using a 12v psu? Defo only supposed to be 9 ( hence the 1.5v batteries x6 ) Would that have anything to do with it making a hum? I'm a bit worried in case my new PSU is gonna hum now.......