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My sid module from SmashTV is a little wonky, what could be the problem?


tarzan boy
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Hiya,

Anyone had this problem before, or perhaps Smash: have you heard of this?

I am currently troubleshooting my full mbsidx4 (see http://www.midibox.org/forum/index.php?topic=6443.0)

When I plugged my lone SmashTV sid module (the others are all from the german shop) into the master core, I got a strange noise. Its stuffed for the 8580, and the noise is a quiet slowly moving (pitch-wise) tone that goes down from high into low nothingness. It eventually goes away, after maybe 6-7 seconds, but the overall volume of that sid module is noticeably quieter (perhaps as much as 10db) than the other 8580 sid module, even when stuffed with the same SID chip.

Also the filter sweeps are really erratic, giving weird hissing noises at different intervals and generally not being smooth or pleasing. And again, the other 8580 sid module does not behave this way.

Could the filter caps be bad and this is the only reason? Would those same faulty capacitors make such a pitched tone when powered on and also affect the overall volume of the module?

I'm assuming it can't be the master Core's software making the error as I do not get this behavior when i plug the other SIDmodule with the same SIDchip directly into the master Core.

I also will note that the caps that come with the german board are smaller with the two legs coming from the bottom of a yellow mass with a blue band, whereas these that came with the Smash set have the legs coming out of opposite sides of a silver tube -- i don't know enough about capacitors to know if these are in fact different 'kinds' of caps or merely different presentations of the same kind.

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Hi.

Smash ships his kits with polystyrene caps which happen to be the BEST caps for tuned circuits (low tolerance, extremely temp. stabile)

BUT Smash also includes caps for both 6581 and 8580, are you absolutely sure You have the right caps for the 8580 in place?

Moebius

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looky looky, i'm an idiot!

My first overtly dumb mistake of the project.

Yes, as i have just disconnected all the boards from the case to debug some problems tonight, i can plainly see  now that I stuffed the 470's instead of the 6.8's, and when i just looked in my jar of unused components, i found my 6.8's just sitting there.

thanks moebius, and try not to judge me!

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(Someone dropped a turntable on it)

Hang the DJ, Hang the DJ, Hang the DJ

Hang the DJ, Hang the DJ, Hang the DJ

HANG THE DJ, HANG THE DJ, HANG THE DJ

HANG THE DJ, HANG THE DJ

HANG THE DJ, HANG THE DJ

Hang the DJ, Hang the DJ, Hang the DJ

HANG THE DJ, HANG THE DJ

HANG THE DJ, HANG THE DJ

Hang the DJ, Hang the DJ, Hang the DJ

HANG THE DJ, HANG THE DJ

HANG THE DJ, HANG THE DJ

Hang the DJ, Hang the DJ, Hang the DJ

HANG THE DJ

Off course this is a lyric quote :D :D :D :D

The Smiths "Panic"

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I'm the DJ

It was my turntable  :o

It wasn't me though

It was only really a test board for my SIDs but then i got another 64 and a 64C that worked and had a bag of cartridges so i didn't have to load anything to test the chips, Just switch em on and go.

I'm actually not too bothered because i'm happy enough to build new SID boards with the extra caps and so on from Smash, He's revised the boards and i don't want to feel left out :)  (Honestly without his boards i wouldn't have ever built the SID)

I have sixteen working SID chips in total, 8 from 64s and 8 from 64Cs, Waiting to be built into two stereo quad monsters :)

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I did something similiar - I accidentally had my two polysterine caps shorted against each other (the two  closest pins on the R3 SID PCB).

One question - Should I now replace those caps?  When they were shorting I was getting very very odd sid behaviour - the synth was essentially busted.  Unshorting them, I now only have an issue with the filter - it quiets my input down nothing whenever I use it.  Can I test the caps with a multimeter?

Cheers,

Tom

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Can I test the caps with a multimeter?

my multimeter can, but i don't think you destroyed the caps (in fact; i think if you destroyed anything, it would more likely be the SID filter section). But, if you got more of the caps, you could change em to be sure

cheers

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Man that's a top design. I will assume that you've pulled one apart (probably many of them), they're just freakin brilliant, the engineering is so damn good. I will never forget looking at the inside, thery're just....so...chunky. Mmmmmmmmm, chunky. Don't drop one on your foot though, yuo'll probably need a plaster cast and crutches ;)

mmmhm, 1210's... Smashing the myth that "They don't make 'em like they used to"  ;D

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