Help! I blew up my MC202!! :( *Fixed! Thank You :)
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Re: Help! I blew up my MC202!! :(

by JRock on Sat Jan 29, 2011 7:42 pm

How would it have gotten a short?
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Re: Help! I blew up my MC202!! :(

by guest on Sat Jan 29, 2011 8:22 pm

something must have gotten destroyed
when you plugged in the cv
so the short is inside a component

what was the exact sequence of events you went through
before the synth stopped working
are you sure your connector went to the built in synth cv out
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Re: Help! I blew up my MC202!! :(

by JRock on Sat Jan 29, 2011 9:06 pm

Well I tried it in the int. Gate out and the external CV and gate and I accidentally plugged it in to the CV in. At the time I didn't think it should be a problem cause there shouldn't be any signal coming out of the CV in of this module I'm working on. It's just a Datasheet typical connection for the SSM2044.
So I was playing the audio through this filter and It was tough to tell if it was working because the VCA envelope is the same as the Filter envelope. So I ran my DR110 into the audio of my module and tried to control the CV with the MC202.
I tried the ext. CV and the gate and none of it was working. So I switched it back. I was connecting different lugs from the pots on the module just to see if this did anything for most of this. I looked and saw that it was plugged in to the CV in (by accident) :oops: so I switched it back to int.CV out.
I still couldn't get it to work so I thought I would plug the audio from the MC202 back in to see if the drums were just too fast to hear it working. It was busted so I posted up here.
The reason I thought I may have fed it -15V was cause the frequency pot has +/-15V attached to it. Now I didn't intentionally hook either of them to the V/oct or the CV pot but I am debugging this module, so... :cry:
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Re: Help! I blew up my MC202!! :(

by guest on Sun Jan 30, 2011 5:12 am

check ic13 and ic18

was there any other connections between the two boards
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Re: Help! I blew up my MC202!! :(

by JRock on Sun Feb 06, 2011 10:21 pm

Sorry for the delay. It's been a busy week.

IC 13 is a TL082 made by JRC? I can't find a datasheet on it.

Should I be checking the resistance to ground from the negative power rail or should I pull them?
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Re: Help! I blew up my MC202!! :(

by guest on Mon Feb 07, 2011 6:19 am

the tl082 is a very common opamp
so you can replace it with another one

you might as well measure the resistance first
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Re: Help! I blew up my MC202!! :(

by JRock on Tue Feb 08, 2011 12:07 am

What I meant was IC13 is JRC and it's either 082 or 2127 and I can't find the datasheet on either of them. It's labeled :
082
JRC
2127

on the chip.
After googling both of them (as JRC 082 or JRC 2127) I'm just assuming that it's a TL082 cause of the 082 on the chip. I have a fistful of TL082 but since I wasn't able to find the datasheet and confirm that it is just a different brand I wanted to doublecheck so I know which pins to check. If it's definitely a TL082 then I can just go ahead and replace it but I wanted to be sure
I guess I could check the schematics :lol:
Thanks
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Re: Help! I blew up my MC202!! :(

by aminoacid on Tue Feb 08, 2011 8:11 am

its a njm082
my machines kills fascists!
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Re: Help! I blew up my MC202!! :(

by JRock on Thu Feb 10, 2011 12:16 am

Thanks!
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Re: Help! I blew up my MC202!! :(

by JRock on Wed May 16, 2012 6:14 pm

Busted out the ol' MC202 today... I pulled the power pin for the CEM3340, with a little solder braid.
Wouldn't you know it! Negative rail back online!!!!

So I swapped it out and Voila! MC202 Back In Action 8)

Thank You!!!!
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Re: Help! I blew up my MC202!! :( *Fixed! Thank You :)

by SubStyler on Wed May 16, 2012 6:55 pm

JRock wrote:Busted out the ol' MC202 today... I pulled the power pin for the CEM3340, with a little solder braid.
Wouldn't you know it! Negative rail back online!!!!

So I swapped it out and Voila! MC202 Back In Action 8)

Thank You!!!!

Great job!
electronics consists to 80% of superstition and to 20% of fairy tales • DIY or die!
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