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There were some schematics attached to this thread about the mod but they seem to have gone... http://forum.grailtone.com/viewtopic.php?f=5&t=11262&p=78316&hilit=+andrew+mod#p78316

http://tubefreak.com/s-main2.gif Check Return-B jack socket (if you're not using it) and give it a good clean out: Spray some switch cleaner onto a 1/4" jack plug and give it good hard bully-ramming. Other than that: V22 dude.

manual quotes Recto Pre 1Amp @ 117V .... I'd use 200-300VA just to be on the safe side. HTH

+1 plate resistor. Check for correct resistance/continuity from 450V rail (big cap) into pin 1 and pin 6 of V23 socket thru the 82k and 270k resisitors respectively. I bet one of them is open circuit. Snap the culprit in half with needle nose pliers then solder a new resistor onto the legs of...

Was FU2 definitely diconnected when you tried FCB1010? ....if it was: Unlikely to be a single LDR problem. Sounds like the 6406N chip has had it. I've heard of this happening from time to time. If you're lucky the chip will be mounted in a socket and you can just pull it out ... no more...

+1 anode resistors .... Caused me no end of s**t.

Hey... I've pulled LDRs out of my Quad that I KNEW to be faulty but then couldn't get them to go wrong on the bench under the meter! They're strange things. Just replace them all ... it's just easier - Re elvis. Also check plate voltage into V1A. If the resistor's breaking down a low voltage...

Pull Deep somewhere in this thread.... http://forum.grailtone.com/viewtopic.php?f=5&t=47177

generally, if there's a problem with a TX it would get f****n hot but it shouldn't damage anything else in the pre. Just keep an eye on it but otherwise I wouldn't worry too much unless the hum becomes unbearable.

Dude... Quad mains TX should be same. http://www.tubeampdoctor.com/en/shop_Transformators_mains_transformers/Transf_MAINS_for_MESA_Quad_Preamp_Export_Versio_891 Will work on both US or export voltages (dont know which you have) Don't really know what kind of humming / vibration level would...

Thanks for the plug dude! That is one sick rig you've built there.....sounding great too!! Let's just hope my repair work holds up lol :oops: ...!

Are you using FU-2? Try unplugging that first. To temporarily select channels, take a 1/4" (6.35mm) jack plug and short the tip and screen together. Use it in the channel select jacks on the back panel. If the fault goes away there's a good change the footswitch is fried (better that than a...

I've still got a few PCBs left if you want me to build one for you.... I've run out of boxes so you'll need to find some way of housing the unit. IM me if you want more info on it.

Sorry dude, not going to happen. Unless you get the export version you're going to need a step-down tx. http://tubefreak.com/50502.gif ...otherwise it's a new transformer, fan, varistor, fuses etc.

use the two relays in the FCB to control CH-1 and CH2 and then use the two relays in the G-major to control the other two channels in your roadking (you'll need a 2-mono to stereo 'Y' or insert connector lead for the the G major) That's the cheapest and quickest way for now.... hth

Non-midi quad has two reverb tanks... Midi version loses a tank to make way for the midi control circuit board. not sure how this would affect sound quality of the reverb because i've never heard a midi quad but this is only difference as far as i know... hth

I modded my Formula just to see what would happen and overall, I think I prefered it with the mod... It doesn't really alter the tone as such but I found that the mod made the EQ more usable with higher gain settings on the Lead channel. I could dial in more bass without things sounding muddy...

Nice rig! I enjoyed owning my Formula too. As you say, the cleans are something special. I was stupid to sell it really. Do you know if yours has had the 'Andrew mod'?

OK... So, I had Wolfy's QUad in bits all last week so thought I'd have a look at the Pull-Deep circuit and see what's going on. I drew a pic: http://i926.photobucket.com/albums/ad109/tonemonkey1/QuadOP.gif Looks like you're right! The Channel-1 pull-deep is on the A-output and the Channel-2...

That's a strange one. I've got a friend's Quad in bits on my bench this week so i'll have a look at where pull-deep comes from- might explain what's happening.