Bertiebee

Quad 33 was working, now isn't - any ideas?

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I was testing Quad 33/405-2 amplifiers for my brother this morning (when put away some years ago there was apparently a hum). Plugged it all in and it was working this morning (listening via CD) - turned off to move the CD player and now it won't power up again.

Now, when the 33 is turned on there is a 'bump' (always has been), the red light on 405-2 lights up briefly and then goes out (the power amp powers up fine if I just plug it directly into the mains via a kettle lead) - there is no light on the 33.

I've tried changing the fuse in the mains plug and also the fuse on the 33 (don't have an exact replacement to hand though).

Any ideas would be gratefully appreciated.

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I thought I couldn’t leave this unanswered but I’m not overly qualified either lol. I’m thinking power supply at fault but depending on where you live, there are still some people around that would be able to check and fix for little money... where do you live?

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23 minutes ago, radiant red said:

I thought I couldn’t leave this unanswered but I’m not overly qualified either lol. I’m thinking power supply at fault but depending on where you live, there are still some people around that would be able to check and fix for little money... where do you live?

Live in Leicestershire.

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Super Wammer

I can't remember if there's some sort of protection in the 405....  The thump might be tripping that. And if you power it up without the pre, there's no thump so it doesn't trip. What happens if you power up both but without the interconnect, then plug that in?   TBH, I don't think there's electronic protection, only a fuse, but if you're getting a power light sometimes, it shouldn't be hard to troubleshoot.

Plenty of circuit diagrams on the internet.

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I can't remember if there's some sort of protection in the 405....  The thump might be tripping that. And if you power it up without the pre, there's no thump so it doesn't trip. What happens if you power up both but without the interconnect, then plug that in?   TBH, I don't think there's electronic protection, only a fuse, but if you're getting a power light sometimes, it shouldn't be hard to troubleshoot.
Plenty of circuit diagrams on the internet.

Just tried that and the 33 doesn’t power up at now. Done the obvious thing and ordered a replacement 2A fuse to see if this is the culprit (fingers crossed).


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