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Old 22nd Nov 2022, 8:17 pm   #32
waynej4
Triode
 
Join Date: Nov 2022
Location: Chatham, Kent, UK.
Posts: 16
Default Re: Quad II problem - Rectifier blowing (GZ32)

Quote:
Originally Posted by theredhouseinn View Post
On the good amp you have got 3 blue wires on the GZ34 base, on the bad amp you have got 4 blue wires on the base. The extra blue wire is connected to the same tag as the brown wire. Or so it seems on the pic..
John.
The 4th wire is there, it's just hidden behind the high voltage wires.

Quote:
Originally Posted by PYE 405 View Post
Going forward to when you have them working nicely, a little tip worth thinking about is what I have done with mine.
It is very simply to replace the 2A mains fuses with T750mA fuses. I do this because it offers a bit better protection, yet they still operates fine with my 22 and FM tuner connected. They have been like this for a few years now. (You need an anti-surge fuse to prevent any annoying fuse blowing from switch-on surges).
I've also seen a Quad mod where they install a 250ma fuse on the high voltage line after the rectifier. I assume this is also a good thing to do?

Quote:
Originally Posted by cathoderay57 View Post
As far as the DC resistances of the output transformer primaries are concerned, Keith Snook says:
X-Y 115 to 125 Ohms
Y-Z 170 to 190 Ohms
Therefore your measurement of 120 Ohms X-Y on your good amp is good; 300 Ohms on the bad amp is bad, but make sure you were measuring the right terminals and that the meter probes were making a good connection. It's possible that you were measuring X-Z on the bad amp........ Jerry
Double checked (always a good idea!), and it is just over 300 Ohms on the bad amp.
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