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1997 SWR california blonde I REALLY odd problem.. HELP

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  • 1997 SWR california blonde I REALLY odd problem.. HELP

    I got a California Blonde I made in 1997 on the bench and it blowing my mind. Its been "Fixed" 3 times but owner has been fleeced, I dont roll like that Ill give it back for free though Ive spend the day trouble shooting with no luck. He has been ripped off too many times. First off I cant find the schematic.... but the issue is strange channel 2 works fine channel 1 with the gain and master volume for both channels and aural enhancer presents AC interfearance badly,,, like if my solding iron is plugged in on the same line/outlet the gain buzzes badly but not channel 2 I plugged into the fx sends for channel 1 and NO buzz when run to my mackie power amp in powered mixer, BUT when I plug into fx send 2 BUZZ AND when I plug guitar into fx return 1 no buzz yet volume and gain effect the level of the return signal....When I plug into fx return 2 nothing amp cut off totally..... It has a Mercury tranformer I suspect some tech sold him, I assume they didnt come with a Mercury tranny stock.... lots of dull grey joints outputs looked replaced they melted the top of a few small poly caps but I dont think it major. I found 1 schemo showing 12 tlo72's in this machine but this has only 9 and one LM380n mounted reverse of all the tlo's I believe it is running to the headphone switch or appears too anyhow...This man is a gigging musician and is leaving for a small 13 day tour wed. so I got one day left to try and sort it out..I know I should have posted earlier I had it for the weekend but wasnt expecting this to be such a head scratcher... He said it pick up buzz on the road and cant use really... I thought I had this narrowed down to channel 1 preamp but with all this I am bewildered... ANY input would be great I was thinking ground loop but all connections look to be correct nothing burned or suspect in appearence other than maybe to much compound on the outputs....they used a bunch....Oh it also makes a funky pop and sverft....several seconds after switched off Any takers or insight would be apprecieated very much....Im considering lending him my Fender Acoustasonic Jr for his tour... Ill be up late I got the channel 1 board pulled up and am going to touch up the joints for now... Thanks Guys.......

  • #2
    Ok I did see that they did come with Mercuries in the early days and for what its worth the horn is blown but I unplugged it and had on effect on issue ..

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    • #3
      Page 2 of this schematic shows 9 IC's, one of which is LM380 : http://music-electronics-forum.com/a...-blonde-00.pdf
      Originally posted by Enzo
      I have a sign in my shop that says, "Never think up reasons not to check something."


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      • #4
        Thank you G-one for the schematic I have some tlo72's Ive been swapping but to no avail...it kinda acts like a PS/ transistor issue, yet the preamp board is my main focus right now as it goes away when I use the fx return for chnl 1so that is why I am in the pre board now..Very strange issue thanks again for the pages I will be checking voltages......The amp seems to work fine if it has nothing else on the ac outlet line,when my Iron station is on is when it buzzes which is kind of normal but why only the 1 channel and channel 2 is perfectly quiet no noise/buzz at all with iron on. This is his main problem and why he brought it in. it picks up noise from the bars ac outlets Mind it is bad not mild, very loud.. Thanks again
        Last edited by Smitty02; 03-05-2013, 04:50 AM. Reason: add more info

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        • #5
          I ended up re-soldering much of the channel 1 preamp board and ran new ground wires as it was not grounding properly. I run it into my pa using the grounded line out and then the 1/4 line out, it is quite as a mouse now even with soldering station running on same line... Very odd I usually dont run accross these type of problems but I guess he had several other people work on the amp so... I was left to figure it out...All seems well now.

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