Quad 405 upgrade - Step 3 - cannot find C17

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23-Jul-2019 01:58 PM

Pholipe

Pholipe

Posts: 11

Hello,

I am blocked at Step 3: Upgrading circuit boards; and I started to found the components on them.

I have to remove the C17 but I cannot found it anywhere; not on the circuit board except if it could be a little capa (1 n) on the back of the board without any other identification ?

The documentation says that C17 could be on the clamp circuit but on my Quad, there is no identification of the components on this little board soldered on the entries of the LS, only "M12400 ISS2".  Can I send you pictures  ?

Many thanks because I am blocked .

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24-Jul-2019 02:32 AM

EJP

EJP

Posts: 1677

C17 is the 10uF bipolar electrolytic capacitor on the clamp board. If you don't have a clamp board you either have a 405-2, in which case it is on the main PCB, or else you have an early 405 without a clamp circuit.
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24-Jul-2019 08:42 AM

Pholipe

Pholipe

Posts: 11

Hello. Happy to have news from you.

My Quad has a serial number 46192 and so it would be a 405-1.

On the clamp board - if it is the board I removed from the entries of the LS ? - there are 2 capacitors written 10/40 so my question is : are both identified with the same value C17 ? One for each circuit board ?

On the other side, I bought to you 2 DC Protection and Delay units I installed and I removed the original protection board.

If I follow the upgrade guideline, I have to replace the C17 and I did not read in it that I can bypass this replacement if we replace an existing original protection board by yours.

Could you be so kind as to confirm or may be I am wrong.

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24-Jul-2019 10:16 AM

EJP

EJP

Posts: 1677

Yes there is one per channel, yes you've identified it correctly, and yes if you are replacing the whole clamp board you don't need to renovate it.
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24-Jul-2019 11:29 AM

Pholipe

Pholipe

Posts: 11

Thank you very much for your quick answer and help.
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