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Pioneer SA-9900 problem

C

Clay1955-7

Member
Hello all; I traded for this 9900 a little over a year ago, it has never really had the sound that it should, I have plenty of amps so I just recently decided to look into it. I added 3 pictures this is on the AWR-070 board. Someone had put 1000uf caps where the 470uf should be and I guess did not have enough room so ran wires to the 2 caps you can see in the middle pic and hot glued them down making a real mess. The 3rd pic is the board after I rebuilt it and set the voltage on it. So I’m thinking its going to sound great - wrong now I have a very faint roar with the very slightest hint of music. Checking the switches the balance makes static (not from oxidation) the high filter makes a slight noise, but the real kicker is the low filter kicks on the protection relay. So if anyone has a clue please help, thanks
 

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The clue I picked out is that the low filter would be a using a capacitor. If you flip it on, the relay kicks? You have DC leaking somewhere. Check the voltages from the power supply and there might be a leaky cap someplace...
 
Possibly you have multiple issues
- noise/low audio
- DC spike when low filter activated

Connect iphone or whatever (minimum volume) into the main-in RCA at rear, set switch to seperated, play audio on iphone, slowly increase volume, audio ok would point to preamp issue.
 
OK going through the preamp input with IPhone, it sounds great, so I think I’m going to rebuild the tone AWS-080 board, I was going to do that anyway, but i need replacement for the 2 - 2SK30A transistors, there or some 2SK30A on eBay, is there something I can use other then them
 
Clay1955-7 said:
i need replacement for the 2 - 2SK30A transistors, there or some 2SK30A on eBay, is there something I can use other then them
Click to expand...
I wouldn't replace them unless they were suspect faulty. The bay is risky. Not up to date on the latest fets, maybe 2SK209, others know better
 
I would leave those 2SK30A's alone if they work, difficult to find proper replacements in some pioneer power circuits for them.
 
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