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Mark IIC+ Schematic (correct!)
http://forum.grailtone.com/viewtopic.php?f=27&t=74680
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Author:  jrb32 [ Tue Feb 20, 2018 8:41 am ]
Post subject:  Mark IIC+ Schematic (correct!)

Hi Guys,

I was so annoyed with all the misinformation out there that I've HOPEFULLY drawn up an accurate IIC+ schematic of the main sections. I say hopefully because I do not own a IIC+ and cannot verify this info. This is taken from info I can find on here from chipaudette who had a IIC converted to a IIC+ by Mike B and all the great IIC+ info from Boogiebabies that's on here. Thanks so much for this info!

It's also taken from my experience of verifying my Early III Black Stripe, the mainly accurate schematic from the sloclones forum and chipaudette who drew up a IIC schematic here and took some gut shots: https://get.google.com/albumarchive/109 ... source=pwa

Please let me know if there are any errors. But please only from someone who has a genuine IIC+ to verify with!

Anyway the schematic is here. Hope it's of use to someone! Main things to note that differ compare to the official schematic are the various values used for certain components, and the power section.

EDIT Updated to 100% correct from tracing a IIC I bought and from pictures from a IIC that had been upgraded to a +

IIC schematic: https://drive.google.com/open?id=1mpJFs ... 81rlggkt6M
IIC+ schematic: https://drive.google.com/open?id=1ieTnM ... RIDwbLAcUQ

Enjoy!

Jon

Author:  jediguitarist [ Tue Feb 20, 2018 12:51 pm ]
Post subject:  Re: Mark IIC+ Schematic (correct!)

Wow. Great work! I wish I even remotely knew what any of that means. Hahha.

Would be awesome to be able to troubleshoot my amps instead of just changing tubes and hoping that fixes the problem. :lol:

Author:  tony777 [ Thu Feb 22, 2018 9:59 am ]
Post subject:  Re: Mark IIC+ Schematic (correct!)

Awesome!!!!

Author:  lions [ Fri Feb 23, 2018 12:03 am ]
Post subject:  Re: Mark IIC+ Schematic (correct!)

This was really useful for me for comparing my Mark III for the + mod!

The 100k resistor after the volume you've labelled as optional, is that for the ++ mod? It's not on the other schematics I've seen or anything for the Mark IIIs.

Author:  jrb32 [ Fri Feb 23, 2018 7:54 am ]
Post subject:  Re: Mark IIC+ Schematic (correct!)

Quote:
The 100k resistor after the volume you've labelled as optional, is that for the ++ mod? It's not on the other schematics I've seen or anything for the Mark IIIs.


It's a remnant of upgrading a IIC to a IIC+ that Mike B leaves in. Info I got was from here: http://forum.grailtone.com/viewtopic.ph ... 49&start=0

I don't think it has anything to do with the ++ mod but certainly wouldn't harm anything and would definitely add some gain when combined with a 10pF on V2! Try it and see :)

Author:  jrb32 [ Thu Apr 12, 2018 7:34 am ]
Post subject:  Re: Mark IIC+ Schematic (correct!)

Link updated to include correct EQ and Power Section, along with a few corrections from info out there. This includes, hopefully, the mystery EQ cap.

It also gives info on the ++ Mod. There seem to be two versions so have included both. One involves a component addition and the other includes adding a relay to switch similar to the Mark III.

I have no concrete info on the Reverb or the High Voltage Supply for a IIC+ so cannot compare these at the moment. Apart from that is pretty much as accurate as you'll get until someone traces theirs or offers me one to trace 8)

https://drive.google.com/open?id=1ieTnMLeSiNDoXu_9Or0ky2RIDwbLAcUQ (same as link above - updated that as well)

Thanks,

Jon

Author:  jrb32 [ Wed Dec 12, 2018 12:09 pm ]
Post subject:  Re: Mark IIC+ Schematic (correct!)

Link updated to include 100% correct info. As in I bought a IIC, traced that, then compared it to a C+ from pictures from an upgraded C+ that was originally the same as mine. Then added info I can find on here and other pictures I've seen of factory IIC+s.

IIC schematic: https://drive.google.com/open?id=1mpJFs ... 81rlggkt6M
IIC+ schematic: https://drive.google.com/open?id=1ieTnM ... RIDwbLAcUQ (same as link above - updated that as well)

Enjoy!

Jon

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