QUAD 405 transformer polymer breakdown

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#42
The Quad repair guy told me that humming transformers because of the old potting and the weight IS a standard problem found in many Quad 405. He said one of his customers placed the transformer outside in a casing...

I forgot to tell this, he said he "stopped with 405". So I asked why. He then said that 303 sounds way better 😀
 
#43
JMFahey said:
You simply were above.
You are not THAT important to be the focus of all answers, read the whole thread, it´ll do you good.

So move aside, you are in the path.
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My words were 'simply above'. Take a look. It's up there in black and white. You quoted me, and then addressed a number of comments to 'you', which in the context can only mean me. I'm just trying to disassociate myself from it all, but don't pretend that I'm making anything up here. Your mistake.
 
#46
Yep.... toroid time or even a similar rated standard type of 35+35VAC transformer time. That should at least make the removal of the mess easier and get rid of the original problem in one. Connecting the secondary windings correctly is essential though - a trap for the unwary.

There are always cheats and fools who believe that you fix things with cans of goop, such as automotive body filler. I would have thought it was obvious that you don't actually fix anything that way. The hardened goop just buries or immobilises the problems so you don't hear or see them - at least for long enough to fool the next sucker.
 
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#48
No, I've only restated the spec. for the power amplifier secondary windings. The transformer suggested in #4 is typically an economical, off-the-shelf product. Adding a 300VAC winding is only required for ESL speakers if you already have or can afford them. Few users have the original Quad models in good working condition now and you would also need to pay the price of winding a single 300VA custom toroidal transformer which incorporated the 300V winding. It would be rather expensive and unwise for a newbie to be figuring out and messing with that, I think.
 
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#52
Ian Finch said:
There are always cheats and fools who believe that you fix things with cans of goop, such as automotive body filler. I would have thought it was obvious that you don't actually fix anything that way. The hardened goop just buries or immobilises the problems so you don't hear or see them - at least for long enough to fool the next sucker.
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There are many that work this way unfortunately. Since a certain online sales channel was created they also had an easy way of selling such items.
 
#54
As someone who have been dealing with removing epoxy with heat at a previous job.... I find it weird to see it liquidify, we literally use a solder pot to soften, then peel it off. Later I switched to heat gun to reduce the mess. It turns into the consistency of common eraser when it is heated up beyond water's boiling point.

I find it very weird that it completely liquified and poured out with heat. Maybe the unit was already like that before shipping, and the seller was trying to hide damage or hide repairs with his/her own formula of gray goo, except this version of gray goo melts in heat.
 
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