FYI Chinook Owners -- Diode Failures and Repair Upgrade


Hey There Manley Chinook Owners!

My Chinook stopped producing sound a few weeks ago.  All tubes checked out fine as well as connections.  I checked on things and everything looked great.  I was stumped. 

I placed a customer service ticket with Manley.  Well, the lovely EveAnna Manley contacted me herself!  Wonderful person and a great business owner in this hobby--in my humble opinion. 

At any rate, Ms. Manley informed me that several diodes (On the power supply board, D9, D10, D11, D12) need to be replaced with some Micro Commercial Components (MCC) Schottky 5A Barrier Diodes Part# SR5200-TP.  I think the previous values were lower amperage and now Manley specifies 5A.  

My unit is out of warranty so I told EveAnna that I'm decent with a soldering iron so I'd give it a go myself.  She said if it doesn't work her guys could fix it.  EveAnna was super gracious and offered to send a tech bulletin and the schematic to make my surgery easier.  

By the way, (and I'm paraphrasing here), I think EveAnna mentioned that not everyone will have this issue.  It does, however, occur over time.  I thought it might be helpful for other owners to know this as--if you're like me--it's easy to get frustrated when such a great piece of gear quits and I cannot easily diagnose the issue. 


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Showing 2 responses by millercarbon

Rectifier diodes have a HUGE impact on sound quality. High speed smooth diodes will give a deeper more liquid sound. Far be it from me to butt in, but a quick search turns up the part you listed is dirt cheap. In other words, however good that thing sounded before, if you can be persuaded to crack open your wallet for some $5 hexfreds (or whatever, anything will be better than SR5200-TP) you will be floored at the improvement.  

I've done diode swaps like this before. One of the more astounding improvements you can make. Why everyone gushes and obsesses over caps while never mentioning diodes, is beyond me. Just do it. You can come and gush and thank me later.