x0xi0 IO & Overdrive - Install & Troubleshooting
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Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by moogah on Mon Aug 08, 2011 5:15 pm

I'm working on an x0xi0 output board for a friend and I'm a little stumped. I've finished the directions on the alphazone site, but I can't download the .pdf manual which I'm starting to wonder if it contains more than what is on the web itself. In particular, I can't find information about what R62 is supposed to be replaced with (so at the moment the VCO doesn't connect to the VCF) and I also can't find information on what r344 is supposed to be.

I may have received some parts that belonged to the full kit as so far I've not needed most of the parts in the bag labeled "x0xb0x Mainboard Parts" and I've also got leftover 47n, 470n and 1uF box caps along with a few resistors... I had to triple check this because I know bc has a solid reputation with his kits so it doesn't seem likely that so many parts were out of order.. yet I'm pretty good at this myself so I'm fairly confident that I've not simply stuffed incorrect parts in the board.

Apologies if I've just missed something obvious :)

EDIT: I see Raph sorted some of this out already.. feel free to ignore the redundant questions, I'll make another edit in a bit once I've worked through what's here
Follup-Edit: Altitude has the correct info reguarding R62. I've not tested *all* the I/O options yet (need an 1/8" adaptor) but so far so good :mrgreen:
Posts: 186
Joined: Sun Jun 19, 2005 8:51 pm

Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by kroutshev on Wed Sep 21, 2011 7:31 am

i've just finished IO mods into my x0x and distorsion sound is very low, overdrive is ok but not distorsion.
I have followed these instructions => http://alphazone1.com/x0xi0/install/io_section1.html

Any idea ?
Posts: 146
Joined: Thu Oct 30, 2008 9:00 am

Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by spotta on Wed Aug 01, 2012 11:53 am


Just starting my x0xi0 Kit, using install manual v2 and it states that R310 is 1M and then on another page 470k.
Can anyone help me with the correct resistance?

edit: Brian got back to me and provided lots of help - thanks Brian!

Posts: 10
Joined: Mon Apr 30, 2012 5:48 am

Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by Drox on Sun Jul 02, 2017 12:13 am

Hi I am interested in purchasing the i0 mod kit but unsure if any are in stock ATM. Can anyone point me in the right direction to find out. I checked Brian's site but no email contact so I am posting here.

Posts: 2
Joined: Sun Jul 02, 2017 12:11 am

Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by tupinamba on Sun Jul 02, 2017 3:22 am

I'm afraid Brian doesn't make them anymore... And that's a pity.
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Joined: Fri May 06, 2011 5:30 am

Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by Drox on Sun Jul 02, 2017 4:23 am

Ah ok thanks for confirming. I thought that might be the case but cant hurt to ask.

Posts: 2
Joined: Sun Jul 02, 2017 12:11 am

Re: x0xi0 IO & Overdrive - Install & Troubleshooting

by dnigrin on Mon Nov 13, 2017 1:00 pm

Age old thread, but hopefully some x0xi0 builders still on here...

I’ve had a perfectly functional x0xi0 for some time, built by me using the custom x0xb0x boards, but recently VCO1 stopped working (both sawtooth and square waves) after I was calibrating the unit (with it open), and I may have accidentally shorted something? Everything else seems to be working normally. Sadly, Brian just doesn’t respond to emails or calls asking for help any more. I need help in debugging this, as my electronics skills/knowledge are far from expert.

Basically, the part of this circuit in question is no different than a regular x0xb0x. I’m suspicious that one of the transistors (Q24 through Q28) went bad, however the challenge in just replacing all of those around the part of the circuit near VCO1 is twofold: (1) as you all know, these transistors are hard to come by and expensive, and ideally I’d like to narrow things down to just the bad one and replace it alone, and (2) with the x0xi0 board already sandwiched to the x0xb0x board and with all the wire connections, desoldering the two will be a nightmare for me. So I’m going to try and replace the suspect component(s) from the top of the board, and it’s a very tight spot too. So again, focusing in on the bad component(s) is key for me.

The VCO1 area of is the top right cluster of components, you can see the transistors I’m suspicious of on page 19. This is a big pdf, it takes a while to load: http://x0xi0.com/downloads/x0xi0_build_custom_pcbs_standard_enclosure.pdf

Also, here’s the circuit diagram, I’ve circled the area that corresponds to VCO1. Output #2 should be the square wave, #3 should be the saw (per page 85 of the build manual above).

I already tried swapping out IC11 – no change. I have a digital multimeter and an oscilloscope. Are there measurements I can do to assess exactly where things have gone bad?

Thanks for reading through this long post and for any help you can provide!
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Joined: Fri May 15, 2009 5:24 pm

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