paul cbc Posted May 22, 2003 Share Posted May 22, 2003 Hello, I'm seeking help from the Dynaco & general tube electronics folks on this forum. The other day I turned on my Dynaco st70 and only got sound out of 1 channel(right). Checked interconnects and speaker cables. Swithched both to test and they are not the culprit. Swithched output tubes-el34's and then the 7199's, no dice. Checked bias-right side 1.7 v, left side 46v!! Unplugged unit. I am not very experienced in this area, do have a multimeter and a desire to learn. Any thoughts? I'd appreciate it as I'm pretty bummed right now. My thanks to all, paul Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 23, 2003 Share Posted May 23, 2003 Paul, Your more then welcome to email me your phone number when you ready to test things out and we can trace this down over the phone. Have the unit hooked to speakers preferably cheapo's and on it side with the bottom cover off and your multi meter at hand. craigostby@comcast.net Quote Link to comment Share on other sites More sharing options...
paul cbc Posted May 23, 2003 Author Share Posted May 23, 2003 Craig, Thank you so much for your extremely generous offer to assist me in troubleshooting. I need a blushing smilie to insert here. I am concerned what powering up the unit will do to the output tubes on the left side-high voltage reading. Should I be? I'll try some preliminary checking for basic shortings. Might take you up on your offer though if that is allright(insert blushing smilie). Many thanks, paul Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 23, 2003 Share Posted May 23, 2003 Paul, Were going to fire up the amp without the rectifier tube to find the problem ! Your tubes will not be in any danger ! This way we can find out what has went array with your bias adjustments ! Craig Quote Link to comment Share on other sites More sharing options...
paul cbc Posted May 24, 2003 Author Share Posted May 24, 2003 Update, Well folks I took Craig up on his offer and he called me at home today. Craig spent over and hour with me on the phone walking me through a bunch of diagnostics and measurements until the problem was identified. He did all this from memory too, down to the replacemdnt part # needed. ($1 cost) WOW. I did not buy this amp from Craig. I am blown away by his kindness. After I got off the phone I realised I had forgotten my initial strategy to call him back-he even paid for the phonecall!! I'll post another update on how my repairs go. For now here's to a great guy, Craig NOS Enjoy the weekend, paul Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 24, 2003 Share Posted May 24, 2003 Paul, lets get it fixed then you can flower me with all the smooze !! It should be the problem as long as you were getting proper contact on the resistor ! Thanks Craig PS, My cell phone has free LD and free weekends so no cost to me there so it really isn't that big of a deal. Quote Link to comment Share on other sites More sharing options...
Tom Mobley Posted May 24, 2003 Share Posted May 24, 2003 Craig, >>My cell phone has free LD and free weekends so no cost to me there so it really isn't that big of a deal. Yeah, but your time is. I remember quite well the several hours you spent with me on the phone for nothing. I don't forget either. Some people are better than others and you're one of them. Tom Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 24, 2003 Share Posted May 24, 2003 Tom, Thanks but really I just hate to even think of a needlessly Idle Tube amp . The Tubes should always be glowing it brings piece of mind Craig Quote Link to comment Share on other sites More sharing options...
paul cbc Posted May 25, 2003 Author Share Posted May 25, 2003 Update II, It lives!! The resistor swap seems to have fixed my problem No smoke yet, so I'm hoping my repairs will hold. I'll go easy on the smooze here Craig, but thank you. paul Quote Link to comment Share on other sites More sharing options...
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