Hello.
I accidentally bought a faulty amplifier Quad 405-2. The repairman diagnosed it. It is necessary to change the OPA and a strange detail with 5 contacts. Which is not sold anywhere. I enclose the photo details. Tell me, can you buy this part?
I accidentally bought a faulty amplifier Quad 405-2. The repairman diagnosed it. It is necessary to change the OPA and a strange detail with 5 contacts. Which is not sold anywhere. I enclose the photo details. Tell me, can you buy this part?
Hi aspiens,
I have never seen one bad in my life. If it is truly bad and you can see what it does from the schematic, your repair person might have to make one. I have done that with various sealed modules in Luxman equipment before.
-Chris
I have never seen one bad in my life. If it is truly bad and you can see what it does from the schematic, your repair person might have to make one. I have done that with various sealed modules in Luxman equipment before.
-Chris
It looks to clamp the drive in the event of an overload by pulling pin 4 to pin 1.
If the amp is OK apart from this module then I would say it should work normally with it removed.
The module as drawn also seems to have a major error with one of transistors shown as PNP when it should be an NPN.
If the amp is OK apart from this module then I would say it should work normally with it removed.
The module as drawn also seems to have a major error with one of transistors shown as PNP when it should be an NPN.
Are you 100% sure that is the only issue ?
I'm sure the amp should work normally if you remove it (assuming no other problem exists).
I'm sure the amp should work normally if you remove it (assuming no other problem exists).
I took the amplifier to my repairman. He said not to put these assemblies. Remove altogether. New output transistors Motorola 15009 instead of the damaged. New opa amps OPA604. I hope everything will be fine and the amplifier will work as expected.
There is another question.
I have one more working Quad 405-2. Very strong click in the speakers when turned on. I'm afraid for my Tannoy Berkley.. How is it to win?
There is another question.
I have one more working Quad 405-2. Very strong click in the speakers when turned on. I'm afraid for my Tannoy Berkley.. How is it to win?
I'm not actually familiar with the 405 in use and so can't say how much of a switch on noise you would expect. There is no speaker delay facility and so some noise is going to be normal, and that will appear much worse with high sensitivity speakers.
There were also many versions of the 405 throughout its production run and so it would only be fair to compare like for like.
There were also many versions of the 405 throughout its production run and so it would only be fair to compare like for like.
I could put a block of delay and protection. But a very compact case .. I guess I'll do a toggle switch.
There looks to be enough room to me in the pictures I have seen. A small vertical mounted PCB carrying a couple of relays together with a really simple delay circuit should fit nicely.
N1 and N2 contain the output transistor drivers and it will not work properly without them!
Easy enough to make a couple.
Easy enough to make a couple.
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By puting in the missing part ?
Looks like it makes a gentle turn-on of the powersection.
Mona
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