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Re: VCF issues [WILLZYX KIT]

by MMM on Sat Aug 25, 2012 1:38 pm

hywlen wrote:R69 lifted, measurements from the component side at Q12:
7.22, 9.86, 9.68, 9.11, 9.11


Please measure the resistance (while the xoxbox is unpowered) between the two pins that read 9.11

I'm trying to make sure that there isn't a short somewhere. You may also want to look very closely if there is possibly a solder bridge between those two pins.
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Re: VCF issues [WILLZYX KIT]

by hywlen on Sat Aug 25, 2012 2:28 pm

So I scraped inbetween those pins (there wasnt any noticeable solder bridging but to be fair its fairly dark in the room) and now I'm getting voltages much different to before such as 5.33 at each end of Q12. I will solder the components back in that were unsoldered and then report back with outcome of some tests.
From the few quick voltages I already took, I have a good feeling that you've solved the problem!

Many thanks again!
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Re: VCF issues [WILLZYX KIT]

by hywlen on Sat Aug 25, 2012 3:48 pm

Yes I've managed to listen to the filter working now for the first time! In my defence, the short circuit was on the front of the board where I hadn't looked.
Thanks MMM for your quick replies and helpful advice!

All the best
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Re: VCF issues [WILLZYX KIT]

by MMM on Sat Aug 25, 2012 4:22 pm

That's great to hear!

Good luck with the rest of the build; and don't hesitate to ask if you have further questions.
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Re: VCF issues [WILLZYX KIT]

by exagonal on Mon Mar 18, 2013 2:46 pm

Hi all! Sorry if I attack this post but I find the situation very similar to mine. I have problems to VCF section, exactly no sound, though it is completely normal output of the VCO.
Of precise I noticed that, referring to the voltages shown in this image that enclose, I strongly different values ​​with regard to the collectors of Q12, as well as Q13, Q15, and so on ... until Q22, where the voltage in the two emitters arrives only to 1.80V.
The situation regarding Q21 instead appears to regulate.
Any suggestions? Thanks in advance!
Attachments
mainboard_vcf.gif
mainboard_vcf.gif (75.7 KiB) Viewed 472 times
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Re: VCF issues [WILLZYX KIT]

by exagonal on Mon Mar 18, 2013 2:51 pm

If someone wants to give some advice, I moved this post here:

viewtopic.php?f=12&t=38156

THANK YOU !!
exagonal
 
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