Hi all, I have a vintage Sansui AU-217 amp that works fine in low humidity but plays up in high humidity. When it rains it develops an audible hum through speakers (not sure if one or both) and the volume pot gets very scratchy. Can anyone offer any advice on how to rectify. Fortunately I live in Alice Springs so problem occurs only rarely.
Glenn
Glenn
Noisy pots can be caused by two things, wear and tear and also if there is a DC voltage present across the pot that is being "passed on" by the volume control. You only need a few millivolts of DC to make a pot noisy so well worth a check. If its just wear then the real answer is a replacement. Worst option is a squirt with contact cleaner because the effect is usually temporary. Depending on the construction of the pot its often possible to open them up and clean the track and reposition the wiper a fraction so it moves on unused track.
The humidity issue I have no real idea. High humidity as long as its non condensing shouldn't be an issue (for example humidity here is currently 80% and thats normal day in day out for most of the time). Is there any contamination on the PCB etc that could absorb moisture ? You need to pin it down at least to whether its on both speakers, whether its affected by volume setting and whether it happens on all or just one input etc
The humidity issue I have no real idea. High humidity as long as its non condensing shouldn't be an issue (for example humidity here is currently 80% and thats normal day in day out for most of the time). Is there any contamination on the PCB etc that could absorb moisture ? You need to pin it down at least to whether its on both speakers, whether its affected by volume setting and whether it happens on all or just one input etc
AU 217 is a very old machine so usual suspects are there .
after all these years expect dust , corrosion of various types , dirt, soldering issues , and aged caps
None of these things is expensive or difficult to do ...it will require some little money and basic soldering experience to fix .Expect 90% of any problems to be shelf cured when you do the above things .
you may get some help here in the forum but you need to put your hands in to it .If you don't have the skills and understanding of the danger also involved ( this is a mains operated device ) please seek expert help .
Kind regards
Sakis
after all these years expect dust , corrosion of various types , dirt, soldering issues , and aged caps
None of these things is expensive or difficult to do ...it will require some little money and basic soldering experience to fix .Expect 90% of any problems to be shelf cured when you do the above things .
you may get some help here in the forum but you need to put your hands in to it .If you don't have the skills and understanding of the danger also involved ( this is a mains operated device ) please seek expert help .
Kind regards
Sakis
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