Wasn't sure which forum was most appropriate for this. Since I'm about to try and refurbish an SX-9930 (939) I thought the Pioneer forum might be best.
I picked it up at a yard sale. It's in amazing shape and I want to keep it for my main personal set. I was told it stopped working after a lightning strike. I replaced a visibly blown cap (C1 on the chassis) and it fired up and works great, but when using a turntable it definitely needs new transistors on the EQ board and I'd like to recap-refurb the entire unit (in stages). I want to do as thorough a job as I have the capacity to do (lacking any specialized test equipment beyond a multimeter).
I have some questions regarding audio repair that I hope some knowledgeable folks might answer for me. First, I have a bit of experience soldering and re-capping and have been inside many pieces of electronic and audio equipment and (?)successfully repaired them. Though, I have little knowledge of such circuitry. I do it through trial and error, observation and I guess a lot of luck
So, some of these questions may be embarrassingly basic and others may be more technical.
• Should all transistors be replaced, or just those that have historically been identified as problematic/potentially problematic?
• Same with the caps, should all the electrolytic caps be replaced? I understand the main filter caps rarely need replacing, true? Any other types of caps or board positions replaced as precaution?
• I've read here that the replacement caps should be a higher voltage than the originals. Is that STRONGLY suggested or is it okay to replace with ones of the same voltage? If so, how much higher? (I do understand about replacing with Audio Grade, low noise-high gain caps).
• I've been careful and haven't ever had a problem, but how long does it take a capacitor to safely discharge? I've heard mention of ranges from about 15 seconds to 15 minutes. I do understand it would vary depending on various factors, but any general rules of thumb?
• Lastly, for right now Are there any tricks, suggestions, or recommendations for swapping out boards on Pioneers with twisted-wire pins? I bought a few boards to more easily rework on the bench, but when starting to swap with the board in the unit, discovered that neatly pulling those pins isn't as convenient as I expected it to be
Thanks for any help or answers!!
I picked it up at a yard sale. It's in amazing shape and I want to keep it for my main personal set. I was told it stopped working after a lightning strike. I replaced a visibly blown cap (C1 on the chassis) and it fired up and works great, but when using a turntable it definitely needs new transistors on the EQ board and I'd like to recap-refurb the entire unit (in stages). I want to do as thorough a job as I have the capacity to do (lacking any specialized test equipment beyond a multimeter).
I have some questions regarding audio repair that I hope some knowledgeable folks might answer for me. First, I have a bit of experience soldering and re-capping and have been inside many pieces of electronic and audio equipment and (?)successfully repaired them. Though, I have little knowledge of such circuitry. I do it through trial and error, observation and I guess a lot of luck
So, some of these questions may be embarrassingly basic and others may be more technical.
• Should all transistors be replaced, or just those that have historically been identified as problematic/potentially problematic?
• Same with the caps, should all the electrolytic caps be replaced? I understand the main filter caps rarely need replacing, true? Any other types of caps or board positions replaced as precaution?
• I've read here that the replacement caps should be a higher voltage than the originals. Is that STRONGLY suggested or is it okay to replace with ones of the same voltage? If so, how much higher? (I do understand about replacing with Audio Grade, low noise-high gain caps).
• I've been careful and haven't ever had a problem, but how long does it take a capacitor to safely discharge? I've heard mention of ranges from about 15 seconds to 15 minutes. I do understand it would vary depending on various factors, but any general rules of thumb?
• Lastly, for right now Are there any tricks, suggestions, or recommendations for swapping out boards on Pioneers with twisted-wire pins? I bought a few boards to more easily rework on the bench, but when starting to swap with the board in the unit, discovered that neatly pulling those pins isn't as convenient as I expected it to be
Thanks for any help or answers!!