Big_Stu Posted September 19, 2015 Share Posted September 19, 2015 For the first time in 20+ years I'm having trouble with my hi-fi, it's one of them annoying occasional faults that I can't pin down. Every so often on only some sources (usually the CD, occasionally the radio) the right speaker volume drops, not while playing but when changing sources. In trying to check that it was the amp at fault I broke the whole system down to try various options. On putting it back together i had a hell of a problem getting most of the plugs back into the amp. The plugs are all gold plated, but the amp (Pioneer A400) has only steel connections, which are oxidised. Neither Pioneer or Richer Sounds (where I bought it) wanted to commit to commenting but I'm wondering whether Switch-cleaner like I'd use on my guitar pots would work in cleaning and helping the plugs back on (if I was very careful in squirting it into the plug with not too much so it could short to the other connector). If the oxidisation is so bad I'm also wondering whether it could be the cause of the original problem? All thoughts appreciated. Quote Link to comment Share on other sites More sharing options...
gelfin Posted September 19, 2015 Share Posted September 19, 2015 Not sure if the oxidation is the cause of the innitial problem. Contact cleaner is good. put it on the rca plug then make and break the connection a couple of times, plug in and unplug. This cleans the inner and outer surfaces of the connectors. Also check out your speaker connections, both on the amp and the speakers. Quote Link to comment Share on other sites More sharing options...
leftybassman392 Posted September 19, 2015 Share Posted September 19, 2015 Not necessarily a comment on your situation, but I'm pretty sure oxidation inhibits electrical current. If it's as bad as it sounds they may need to be replaced. Not a difficult job if you're handy with a soldering iron... Quote Link to comment Share on other sites More sharing options...
Big_Stu Posted September 19, 2015 Author Share Posted September 19, 2015 Thanks guys, [quote name='gelfin' timestamp='1442700567' post='2868915'] Not sure if the oxidation is the cause of the innitial problem.[/quote] Neither am I, just trying a process of elimination for now. [quote name='gelfin' timestamp='1442700567' post='2868915']Contact cleaner is good. put it on the rca plug then make and break the connection a couple of times, plug in and unplug. This cleans the inner and outer surfaces of the connectors. Also check out your speaker connections, both on the amp and the speakers. [/quote] That's what I hoped someone would say, I'll give it a very careful go. I'm relatively happy that the speaker connections are OK, they're all gold plated and the fault moved when I switched the speakers connections over. [quote name='leftybassman392' timestamp='1442700732' post='2868918'] Not necessarily a comment on your situation, but I'm pretty sure oxidation inhibits electrical current. If it's as bad as it sounds they may need to be replaced. Not a difficult job if you're handy with a soldering iron.[/quote] It's just that I can see where they looked highly polished before but are now a very dull grey, no corrosion though. I spoke with Pioneer's own recommended out of warranty repair place and they didn't want to touch it as "Pioneer are notoriously bad to get spares off". The connections are on a solid block of 12 so I wouldn't want to try to build a new one. Quote Link to comment Share on other sites More sharing options...
Slipperydick Posted September 19, 2015 Share Posted September 19, 2015 Switch cleaner on the plugs, put them in and out and twist few times, best not to spray it in through the holes. When you change source, does it crackle, and does wobbling the source knob make a difference ? if it does, you might want to try spraying a little into the switch as well if its not a sealed type.. Quote Link to comment Share on other sites More sharing options...
Big_Stu Posted September 19, 2015 Author Share Posted September 19, 2015 (edited) [quote name='Slipperydick' timestamp='1442703002' post='2868934'] Switch cleaner on the plugs, put them in and out and twist few times, best not to spray it in through the holes. When you change source, does it crackle, and does wobbling the source knob make a difference ? if it does, you might want to try spraying a little into the switch as well if its not a sealed type.. [/quote] Definitely - I'll be shaking any excess off the plugs too. I've just tried it with the record channel off the cassette deck (since I can't remember the last time I used that channel ) and it's worked, or at least the getting it back on easily has, I had the plugs wrapped in kitchen paper & shook them a bit before trying. The selector switch is really solid, a very hefty clunk between each source with no wobble or crackle. Edited September 19, 2015 by Big_Stu Quote Link to comment Share on other sites More sharing options...
Slipperydick Posted September 20, 2015 Share Posted September 20, 2015 (edited) [quote name='Big_Stu' timestamp='1442703890' post='2868941'] Definitely - I'll be shaking any excess off the plugs too. I've just tried it with the record channel off the cassette deck (since I can't remember the last time I used that channel ) and it's worked, or at least the getting it back on easily has, I had the plugs wrapped in kitchen paper & shook them a bit before trying. The selector switch is really solid, a very hefty clunk between each source with no wobble or crackle. [/quote] Try wobbling the phono plugs, dry joints on the backs of the sockets if they're pcb mounted is common to most amps. Edited September 20, 2015 by Slipperydick Quote Link to comment Share on other sites More sharing options...
taunton-hobbit Posted September 20, 2015 Share Posted September 20, 2015 Oxidisation on joints can/will cause a resistance problem. I used to service pin tables, and the first step in problem solving was to remove all the power supply fuses, clean the holders & replace with new fuses. Amazing how many problems simply vanished..... Quote Link to comment Share on other sites More sharing options...
Big_Stu Posted September 20, 2015 Author Share Posted September 20, 2015 The CD channel on the amp was the first one to give problems; I've just done the switch-cleaner job on it and it's now clear as a bell. Until now I'd just transferred the CD connection to the spare "line" input. it could be suggestion but I'm fairly sure the CD channel is better voiced that the line, though I'd have thought they were the same thing. I've tried all of the playback lines, given them a wobble on the plugs while they were playing and no crackles. I'll be using it more than normal to test it out, but fingers crossed I/we have found a cure - until next time! Thanks guys! Quote Link to comment Share on other sites More sharing options...
Slipperydick Posted September 20, 2015 Share Posted September 20, 2015 [quote name='Big_Stu' timestamp='1442749911' post='2869170'] I'm fairly sure the CD channel is better voiced that the line, though I'd have thought they were the same thing. [/quote] They are all the same, except for the Phono in. Quote Link to comment Share on other sites More sharing options...
The Admiral Posted September 20, 2015 Share Posted September 20, 2015 [quote name='Big_Stu' timestamp='1442749911' post='2869170'] The CD channel on the amp was the first one to give problems; I've just done the switch-cleaner job on it and it's now clear as a bell. Until now I'd just transferred the CD connection to the spare "line" input. it could be suggestion but I'm fairly sure the CD channel is better voiced that the line, though I'd have thought they were the same thing. I've tried all of the playback lines, given them a wobble on the plugs while they were playing and no crackles. I'll be using it more than normal to test it out, but fingers crossed I/we have found a cure - until next time! Thanks guys! [/quote] Random question, and slightly OT, but Is that a Pioneer cd recorder in your rack? Quote Link to comment Share on other sites More sharing options...
Big_Stu Posted September 20, 2015 Author Share Posted September 20, 2015 [quote name='The Admiral' timestamp='1442786656' post='2869538'] Random question, and slightly OT, but Is that a Pioneer cd recorder in your rack? [/quote] It is yeah, the PDR-609, really great at recording CDs but playback isn't as good as the Marantz. But it does mean I can copy to CD from vinyl, cassette & CDs to very high quality. Haven't done any in years but used to do some "rarities". Quote Link to comment Share on other sites More sharing options...
gafbass02 Posted September 21, 2015 Share Posted September 21, 2015 I vaguely recall from my hi-Fi retail days that the tape in was said to have the most direct route on most amps, but Its a loooong time ago now! Quote Link to comment Share on other sites More sharing options...
Big_Stu Posted September 21, 2015 Author Share Posted September 21, 2015 This amp is direct through on all sources, no bass or no treble pots. The balance control is from dual concentric volume knobs. It also has an input for DAT (remember them! ) Quote Link to comment Share on other sites More sharing options...
The Admiral Posted September 22, 2015 Share Posted September 22, 2015 [quote name='Big_Stu' timestamp='1442787672' post='2869541'] It is yeah, the PDR-609, really great at recording CDs but playback isn't as good as the Marantz. But it does mean I can copy to CD from vinyl, cassette & CDs to very high quality. Haven't done any in years but used to do some "rarities". [/quote] Ive got one which I've barely used, but yes, agreed, great for recording from vinyl, without compressing to MP3. I've often wondered what it would be like with a stereo pair of mics for a live gig, or across the stereo outs from the mixer, but never got around to it. It's probably going to have to go very soon in a big clear out, so it may be up in the for sale section if you want a spare!! Quote Link to comment Share on other sites More sharing options...
Big_Stu Posted September 22, 2015 Author Share Posted September 22, 2015 It would work through a mixer; I made the master of my son's band's live CD with it, not long after I first bought it. I'd bunged the sound guy a few beers to tape it. Only downside was I hadn't accounted for the mics not picking up much audience noise. It was a blinding gig but you can hardly hear the crowd on the final disc. Thanks for the thought with a spare but as I say, it's very rarely used in recent years. I used it for the purpose of this thread for a few A/B tests but that's about it. Last time I used it was to CD some Slade tracks there were never released on digital. Quote Link to comment Share on other sites More sharing options...
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