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Altitude
Joined: 24 Jun 2008
Posts: 165
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 Posted: Wed Mar 10, 2010 1:54 am Post subject: Hallelujah! cue the choir, I FINALLY SOLVED IT |
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So my MB-808 has been sitting idle since I finished it last year. My digital section, flawless. Power supply, perfect. Soldering, impeccable. Analog section, 100% completely fucked.
Nothing worked. I mean NOTHING. None of the instruments were even close to doing anything. Crazy voltages everywhere, massive DC offsets, no output. Nothing made sense. A week of metering, probing, and chatting with Jeff trying to figure out what the hell was wrong was fruitless and the damn thing has been sitting in the corner laughing at me ever since.
Fast forward 1 year to a couple of days ago, I am perusing the x0x forums brushing up on what has been up for the last couple of years since I sold mine (building a second one, running aluminum cases if anyone is interested) and came across a post by Gaetano (the rare parts guy) talking about getting bad batches of various chips including the 2sc945s.
He is in Australia
Futurlec is in Australia
I got my 945s from Futurlec..
I immediately emailed him and sho'nuff he got a bunk set of 945s from futurlec that were sold as 2sc945 but were in fact something called a KC945:
The Futurlec 945
The real 945
The futurlec parts are not even NPN transistors as far as I can tell and give me a fault on my HFE meter.. I guess I better get to work pulling out 55 transistors..
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Doug Wellington
Site Admin
Joined: 26 Apr 2007
Posts: 717
Location: Tucson, AZ, USA
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Lukey
Joined: 06 Jun 2007
Posts: 191
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| Posted: Wed Mar 10, 2010 8:17 am Post subject: |
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funnily enough i just replaced the 945s in my BD and it started working
/edit i have the CP ones, i must have burnt one or something
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problemchild
melbourne australia
http://cycleofproblems.blogspot.com/ |
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Altitude
Joined: 24 Jun 2008
Posts: 165
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| Posted: Wed Mar 10, 2010 3:23 pm Post subject: |
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| Doug Wellington wrote: | EEK...
Anybody want to buy $200 worth of KC945s?
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Just be happy this was caught now and not months from now after kits have been made..
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Doug Wellington
Site Admin
Joined: 26 Apr 2007
Posts: 717
Location: Tucson, AZ, USA
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| Posted: Wed Mar 10, 2010 8:38 pm Post subject: |
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| Altitude wrote: | | Just be happy this was caught now and not months from now after kits have been made.. |
Agreed! 
Luckily, not all of the 2sc945 transistors I have are from futurlec. It was very obvious which ones were which when I opened the packages though...
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Altitude
Joined: 24 Jun 2008
Posts: 165
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| Posted: Fri Mar 12, 2010 4:47 pm Post subject: |
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Well that was 3 hours of complete suckfest getting those damn things out although I can now fully endorse the techspray no-clean #2 solder wick, it is wonderful and leaves no mess.
Note to self: As a rule, more isolation to pads connected to ground plane of future projects
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