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Help needed with Quad II Classic Transformer loose stud problem.

vaathi

vaathi

baski
Subscriber
Hello all... I picked up a pair of Quad II (Original ones with Jones plugs) many moons ago. I have not turned them on yet. In the mean time I got lucky and picked up good looking Quad II classic in good shape with cage. One amp has full set of tubes and another one which has rust in the transformer cover has all tubes but missing rectifier tube. With this set I also picked up Audio Research Classic 30 ( Hybrid Tube Amp) without any tubes. Got some AR headshells with that too.

My question is about one of the Quad ii classic transformer cover is off the base and all the 4 screw posts came loose from the transformer. Wires are intact and I want to fix it with same heavy duty bonding agent which can take heat.. Welding is out of question i guess since it is close to the waxy stuff in the transformer. Any Ideas?

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I wouldn't glue it. You might need access to the transformer. Can you post a clearer picture of where the screw posts have come loose? AK members with metalworking skills will be able to advise. It looks as if the chassis itself is dented on the left of your last picture. Any other damage there?

Great pickup by the way!
 
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Closeup pics of the transformer. As Dandy inferred one of the chassis is really beatup and rusted still looks beautiful. Maybe it was dropped accidentally...

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Looks like it was tack welded originally,, JB weld (epoxy) can take the heat,,, re welding it would burn the finish on the case, so I'd try the epoxy 1st...
 
Thanks John... JBweld has high heat version which can take 450F.. I have ordered one. Now time to hunt down the Schematics.
 
Looks like all the damage is at the end of the chassis. If you can take the output jacks off, AC inlet off and move that circuit board out of the way a GOOD sheet metal mechanic could hammer most of the damage out without destroying the finish I bet. A good old fashioned body shop guy could do it as well. The key is understanding how to move the metal, use proper backstops to back the metal up and experience in doing this kind of repair.

BillWojo
 
Vaathi,

Not sure how wise it will be to do a 'half-job' or temporary one so to speak. I have not seen a Classic Quad, but if it is the same under-chassis as the original Quad II, it does not take a whole lot of time to remove everything and have the chassis repaired properly. If as the original Quad, one need only undo the transformers and choke connections, un-screw the tube bases and lft the whole wiring loom plus sockets plus group board plus Jones plug out carefully as a complete unit. It takes under 20 minutes.You will then have complete access to the damaged transformer, and the chassis can be redone properly, if you were going to have that done anyway. Pitch and transformer terminal board will be in the way, but one can get around that. (I have done it thataway.)


P.S.: Again not sure how old the unit is; on Quad IIs it was also necessary to replace resistors. Some have drifted considerately off-value. But the Quad Classic is rather more recently.

You say 'no time to hunt down the schematics'? They are freely available from several sources on internet.
 
Audiovet said:
Vaathi,

Not sure how wise it will be to do a 'half-job' or temporary one so to speak. I have not seen a Classic Quad, but if it is the same under-chassis as the original Quad II, it does not take a whole lot of time to remove everything and have the chassis repaired properly. If as the original Quad, one need only undo the transformers and choke connections, un-screw the tube bases and lft the whole wiring loom plus sockets plus group board plus Jones plug out carefully as a complete unit. It takes under 20 minutes.You will then have complete access to the damaged transformer, and the chassis can be redone properly, if you were going to have that done anyway. Pitch and transformer terminal board will be in the way, but one can get around that. (I have done it thataway.)


P.S.: Again not sure how old the unit is; on Quad IIs it was also necessary to replace resistors. Some have drifted considerately off-value. But the Quad Classic is rather more recently.

You say 'no time to hunt down the schematics'? They are freely available from several sources on internet.
Click to expand...

I am going to remove the transformer from the chassis and then JBweld it.. When I do that I will also be recapping the unit and replacing broken IEC power outlet. This unit is not over 20 years old and these are revision A reissues based on the Peter Walkers original Quad IIs and some of the cap values were changed. C4 is bumped from 25uf to 47uf. I could not read the value of the two smoothing caps and the rectifier tube is GZ34 instead of GZ32. I am still unsuccessful in finding the right schematics. I even wrote to Quad Hi fi and I haven't got any reply yet. As you suggested, I will try to drop the Circuit after removing the tube socket screws.. Great Idea..
 
Finally found the values for each of the capacitor. Smoothing capacitor in the "Quad II classic" are 150uf 500v and 82uf 500v and 47uf Capacitor instead 25 uf. C1 is .1uf 630v and C2/C3 are .22uf 630v...
 
Got the "Quad II Classic" service manual from the Quad Hifi guys... Uploading it for others who get frustrated as I was not to find it anywhere in the internet.
 

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