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Finally got an OB-8...but it keeps blowing fuses...
Old 13th November 2009
  #1
Finally got an OB-8...but it keeps blowing fuses...

It was a momentous occasion today. The Ob-8 arrived from the US to the UK. Ive been saving for years-litterally...

However I looked on the back and saw '110V or 240V'. Sweet! I went straight for it and as I switched it on there was a POP and I saw a flash. NOOOOOOOOO!!!!
I looked on the back and saw that in my haste I missed there was a small slider that switched the power input that was set at 110V...

Well I spoke to a tech who said it was prob just the fuse. Also he mentioned that there was a difference in the power supply not just in voltage between the US and UK...and I may need a different amp fuse...
I got some new 1A fuses (what it came with) but they blow each time I try to switch on. I tried the 240V and 110V setting (using a converter I had)...they both blow.
I decided to try a 2A fuse - in case this helped. No dice. It blew...

So its just sitting here! I cant even check to see if it all works...

So does the UK power supply need stronger fuses or is there something maybe wrong with the synth?
Old 13th November 2009
  #2
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MonoBrow's Avatar
 

Stop trying and get it to a tech.Something is broke when you seen a flash....
EDIT: you probably blown a cap in the power supply.That was the POP.
I could be wrong offcourse.
Old 13th November 2009
  #3
Quote:
Originally Posted by Fluxpod View Post
Stop trying and get it to a tech.Something is broke when you seen a flash....
EDIT: you probably blown a cap in the power supply.That was the POP.
I could be wrong offcourse.
I think it pops the same each time I try it...
Old 13th November 2009
  #4
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MonoBrow's Avatar
 

ARRRRGGG STOP IT!!!!!
Dude srsl..it wont get any better.The more you try the more there is a chance to BREAK it even more.
Get it to a person who knows about that stuff.And i dont get it you tried it on 110v with a 220 to 110 v converter?
Whatever.Stop trying to turn it on!Please.
Old 13th November 2009
  #5
Quote:
Originally Posted by Fluxpod View Post
ARRRRGGG STOP IT!!!!!
Dude srsl..it wont get any better.The more you try the more there is a chance to BREAK it even more.
Get it to a person who knows about that stuff.And i dont get it you tried it on 110v with a 220 to 110 v converter?
Whatever.Stop trying to turn it on!Please.
the point is a tech gave me the idea that it might be because the UK power supply needs a stronger amp fuse - that why I repeated the test...dont worry Im not doing it again and again!

Can anyone confirm whether or not this higher amp rating idea is incorrect or not? Obviously I dont want to pay a shipping trip there and back for a fuse...
Old 13th November 2009
  #6
Normally a 110/220v switch changes the primary and secondary wiring. Meaning the mains transformer was expecting 110 and you fed it 220 on the primarys.

For sure the fuse was the first to die but that does not mean it was quick enough to stop the extra current from contuning

You`re not understanding current draw here: watts = volts x amps. So for 220v mains you actually need a SMALLER fuse than 110v. Or leave it as it is. As you know fuses are ampere rated like 1A 200mA.. etc.

Probably some other components, diodes, etc could be damaged by now.

Tech for sure.
Old 13th November 2009
  #7
great

oh well-cheers for the help...

Im so gutted. If only I'd taken a second longer to check the back and not been so enthusiastic...theres another few weeks and hundred or so quid down the drain

Last edited by SWAN808; 13th November 2009 at 11:39 PM.. Reason: gutted.
Old 14th November 2009
  #8
Gear Nut
 

I'm starting to consider selling mine again and was going to PM you on VSE as I know you were interested. Then I saw this thread. Good luck, hope it isn't a big deal.
Old 16th November 2009
  #9
Happy Ending!

Thanks to the very generous help of a synth Tech called Jim from Singing Cat Services - I worked out what the problem was. There were a couple of capacitors across the inputs of the transformers - one of which had blown. The Caps only were there to prevent voltage surges - so I could just clip them off (and purchase a outboard surge protector) - and it worked!
This guy Jim is a total legend. He spoke with me enthusiastically several times on a Saturday and talked me through the possible problems. I got a multimeter and learnt some useful stuff. I knew to call Jim because someone a month or so ago told me he was re-building an OB-8 to sell when I was still looking. He had the schematic and everything...Although he didnt know about these capacitors I noticed today and got his opinion on...I was set to buy a whole new transformer until the brainwave about the red caps...

Big Props to Jim!

For those who dont know of him - he is something of a mad genius and regularly modifies synths and is potentially starting a company to build boutique analogue. FOr example we spoke about the opportunity to add an LFO to my Source for the PWM and Sync... Lots of quality Glaswegian banter as well...

Old 17th November 2009
  #10
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chrisrnps's Avatar
 

Sweet!

Now that the OB is working again, time to start saving up for a "Z" or other style of heavier-duty keyboard stand for it and that lovely Source to protect your investment(s).
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