I've got a Yamaha C40 preamp that my father claims is loosing power in either the right or left channel. I Plugged it in and didn't notice a problem with it... so I opened it up to see if I could spot anything weird.
I found that most of the large electrolytic capacitors have a brownish-blackish material that appears to have come out from underneath them. I have attached a picture.
I suspect this is electrolyte that has leaked out of the capacitors. I do not have a lot of experience working with old electronics so I figure I should get conformation from someone who does. It's not a particularly valuable amp (sticker on back says it was made/inspected in '85.... I found one for ~$100 on ebay) but it sounds pretty good and my father likes it.
So my questions are:
Is this electrolytic solution from the caps or something else?
Is it worth it to replace them and clean up the PCB?
What would cause this? Old age? Heat? Some other component failure?
I haven't been able to get it to act up, but I haven't really left it on for any long period of time (maybe it needs to heat up) and I haven't noticed any real sound quality problems as a whole. I appreciate any input. Thanks.
I found that most of the large electrolytic capacitors have a brownish-blackish material that appears to have come out from underneath them. I have attached a picture.
I suspect this is electrolyte that has leaked out of the capacitors. I do not have a lot of experience working with old electronics so I figure I should get conformation from someone who does. It's not a particularly valuable amp (sticker on back says it was made/inspected in '85.... I found one for ~$100 on ebay) but it sounds pretty good and my father likes it.
So my questions are:
Is this electrolytic solution from the caps or something else?
Is it worth it to replace them and clean up the PCB?
What would cause this? Old age? Heat? Some other component failure?
I haven't been able to get it to act up, but I haven't really left it on for any long period of time (maybe it needs to heat up) and I haven't noticed any real sound quality problems as a whole. I appreciate any input. Thanks.
Attachments
even if there is no visible leakage it is possible that 20+ yr old electrolytic caps may need replacing
measuring ps ripple under load could determine if they still have adequate capacitance left or if they have "dried out"
other Al electrolytics in the signal/feedback path could also be loosing C - smaller cases tend to dry out quicker
you could measure the preamp with RMAA to give you the frequency response to see if you're loosing lows on one channel
measuring ps ripple under load could determine if they still have adequate capacitance left or if they have "dried out"
other Al electrolytics in the signal/feedback path could also be loosing C - smaller cases tend to dry out quicker
you could measure the preamp with RMAA to give you the frequency response to see if you're loosing lows on one channel
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.