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Thread: Roctron Silver Dragon Stopped Working ?

  1. #1
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    Roctron Silver Dragon Stopped Working ?

    Hi folks,
    Trying to troubleshoot this Roctron Silver Dragon. The owner says it just stopped working after he tightened one of the case screws that supposedly had a ground wire attached to it. He had it in pieces when he gave it to me ,and there is a black wire that looks like it broke off of something , but I can't see where. Maybe it WAS connected to the case.
    I can only find a schematic ,and not much else available on these. He didn't have the proper power supply as he was using a laptop 12v supply.
    I rigged a PS ,and powered it up grounding the black to the case. Switch still doesn't work. The Slayer side just seems to play though with the switch in either position ,and the Awake side plays through on one position ,and no sound when LED is lit.
    There is another LED used in the circuit (LED3) that I tested with the diode function of my meter ,and it was lighting ,then it stopped. Can a regular diode be used to replace this ?

    Thanks all !
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    Quote Originally Posted by gtrplayr1976 View Post

    he was using a laptop 12v supply.
    I rigged a PS ,and powered it up grounding the black to the case.

    Thanks all !
    According to the schematic, the power supply requires 12VAC; not 12vdc. Most laptop power supplies are 12vdc. What is your power supply providing... AC or DC?
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    Quote Originally Posted by cjlectronics View Post
    According to the schematic, the power supply requires 12VAC; not 12vdc. Most laptop power supplies are 12vdc. What is your power supply providing... AC or DC?
    Well....I feel like an idiot. lol...Can't believe I missed that. I assumed it was like other switches that use dc. Thank you !

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    I only know to ask this because I have done the same thing... don't feel bad. We are human and easily overlook the simple things. Hopefully, that'll fix it.
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    Senior Member Enzo's Avatar
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    Always check the power adaptor for type as well as for function. I always tell the customer to bring along his power adaptor, that way I know whether his trouble has anything to do with the adaptor. We may find when he put his unit back together he just plugged the wrong adaptor into it. But at least now you can determine if there are any other issues.
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    Supporting Member Jazz P Bass's Avatar
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    Had a guy bring me a Casio keyboard.
    Will not power up.

    Where is the power pack?
    Oh, I did not think you needed that.

    Guess what was bad?
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    Quote Originally Posted by Enzo View Post
    Always check the power adaptor for type as well as for function. I always tell the customer to bring along his power adaptor, that way I know whether his trouble has anything to do with the adaptor. We may find when he put his unit back together he just plugged the wrong adaptor into it. But at least now you can determine if there are any other issues.
    I absolutely should have noticed it on the schematic. Just overlooked it. The owner doesn't have the original power supply ,and someone told him he could use a laptop PS ,which I'm guessing he tried. All I really have to use is a variac.

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    Quote Originally Posted by Jazz P Bass View Post
    Had a guy bring me a Casio keyboard.
    Will not power up.

    Where is the power pack?
    Oh, I did not think you needed that.

    Guess what was bad?
    LOL....uh. This guy doesn't have the PS. Someone told him to use a 12v laptop PS.

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    Quote Originally Posted by cjlectronics View Post
    I only know to ask this because I have done the same thing... don't feel bad. We are human and easily overlook the simple things. Hopefully, that'll fix it.

    LOL..not the first time I've missed something simple. Have to hook up the variac. It's the only thing I have that puts out AC.

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    Supporting Member The Dude's Avatar
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    Just had that conversation with a customer last month. I got in a Korg keyboard blown to smithereens. The customer didn't bring in the power supply so I called to ask if he was using the right one or could bring it in. He said, "Well, it fits in the jack, so it must be the right one". It wasn't.
    “Yeah, well, you know, that’s just, like, your opinion, man.”

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    Quote Originally Posted by The Dude View Post
    He said, "Well, it fits in the jack, so it must be the right one".
    Hahahahahaha! Like the time I swapped the 6V6 & 5Y3 in my Champ...

    Justin
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    Quote Originally Posted by The Dude View Post
    Just had that conversation with a customer last month. I got in a Korg keyboard blown to smithereens. The customer didn't bring in the power supply so I called to ask if he was using the right one or could bring it in. He said, "Well, it fits in the jack, so it must be the right one". It wasn't.
    LOL...of course

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    Quote Originally Posted by Justin Thomas View Post
    Hahahahahaha! Like the time I swapped the 6V6 & 5Y3 in my Champ...

    Justin
    So, you had to rewire the sockets to make it work?
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    “Yeah, well, you know, that’s just, like, your opinion, man.”

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    I'll just say I was really happy to have that 11-second warmup time...
    My buddy who didn't realise his 100W Peavey's 6L6s had busted base guide pins wasn't so lucky... he pulls the tubes, puts them back in, and I get a phone call: "hey, I turned my amp on & the tubes lit up like a 100W light bulb?"

    One of my favorite things about working with tubes is the abuse and ignorance they'll survive...

    Justin
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    Senior Member Enzo's Avatar
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    On the other hand, output transistors are rarely plucked from their sockets and put back in backwards.
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    Quote Originally Posted by cjlectronics View Post
    I only know to ask this because I have done the same thing... don't feel bad. We are human and easily overlook the simple things. Hopefully, that'll fix it.
    Connected this FS to my variac set at 13V ,and she works , but hums badly. Could be this black wire that was broken ,and I have no idea where it broke from. Looks like a ground , but grounding to the chassis makes no difference. It's connected to one side of LED3 that shows to ground. Any ideas ?

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    Is Led3 working without that wire connected? It looks to be the 'power on' led.
    Prime suspects for hum would be components that could have been damaged from the use of the wrong supply, like caps or diodes in the supply area.
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    Quote Originally Posted by g1 View Post
    Is Led3 working without that wire connected? It looks to be the 'power on' led.
    Prime suspects for hum would be components that could have been damaged from the use of the wrong supply, like caps or diodes in the supply area.
    I just checked ,and the LED does work without the wire connected.

  19. #19
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    So then that black wire was used to ground something using the same ground the LED3 is attached to.
    Pretty tough to figure out without a very careful visual inspection, unless someone has posted gut shots on the net.
    Can you post some pics of the guts?
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    Quote Originally Posted by g1 View Post
    So then that black wire was used to ground something using the same ground the LED3 is attached to.
    Pretty tough to figure out without a very careful visual inspection, unless someone has posted gut shots on the net.
    Can you post some pics of the guts?
    I have searched up ,and down for gut shots. I have a few at the beginning of the thread.

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    Quote Originally Posted by g1 View Post
    So then that black wire was used to ground something using the same ground the LED3 is attached to.
    Pretty tough to figure out without a very careful visual inspection, unless someone has posted gut shots on the net.
    Can you post some pics of the guts?

    Just noticed something off with the schematic. R38 is missing. Not sure if it was a change, or someone broke it off.
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    Well that seems to have been a change. I also see other strange changes like resistors in places where caps would be according to the board ,and schematic. This is a strange animal.

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    Senior Member Enzo's Avatar
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    "Missing" parts are common in gear, they are just changes. If you ever look at the drawings for some product where you have all ten revisions, you usually find just such changes.

    Frankly, the hum could be from using the variac. For reasons discussed in the widowmaker thread, you might have the neutral side as your hot.
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    Quote Originally Posted by Enzo View Post
    "Missing" parts are common in gear, they are just changes. If you ever look at the drawings for some product where you have all ten revisions, you usually find just such changes.

    Frankly, the hum could be from using the variac. For reasons discussed in the widowmaker thread, you might have the neutral side as your hot.
    Yes sir. That's what I figured after I started looking at the board ,and the schematic.

    I'm pretty certain I have the neutral ,and hot correct. I'm using a polarized plug ,and the end of an old adapter. Would be nice to have the actual power supply.

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    Senior Member Enzo's Avatar
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    Simple test: Set up the unit as you described. Don't connect it to an amp, just the power connection. Now measure for AC voltage between the chassis of the unit and earth ground somewhere, like the center screw of a wall outlet. If you see a few volts, you have the variac backwards.

    You can find a 12vAC adaptor at Radio Shack or places like Best Buy.

    In my shop I had a collection of power adaptors, so I could always have a proper supply for anything. I always tell people to bring their supplies with them, but so many do not.
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    Quote Originally Posted by Enzo View Post
    Simple test: Set up the unit as you described. Don't connect it to an amp, just the power connection. Now measure for AC voltage between the chassis of the unit and earth ground somewhere, like the center screw of a wall outlet. If you see a few volts, you have the variac backwards.

    You can find a 12vAC adaptor at Radio Shack or places like Best Buy.

    In my shop I had a collection of power adaptors, so I could always have a proper supply for anything. I always tell people to bring their supplies with them, but so many do not.
    I will give that a try. Thanks Enzo !

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    The black wire that is disconnected, is it the one in your pic that goes to the tube board bracket?
    If so, it looks like on the schematic it goes to a ground at the AC adapter jack.
    The green/yel wire lug should go to a chassis screw to ground the chassis.
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    Quote Originally Posted by g1 View Post
    The black wire that is disconnected, is it the one in your pic that goes to the tube board bracket?
    If so, it looks like on the schematic it goes to a ground at the AC adapter jack.
    The green/yel wire lug should go to a chassis screw to ground the chassis.
    Yes, that's the wire. It isn't long enough to go to the AC adapter jack unless it's connected to a pad on the board that goes to the jack. The yellow/green has a ring on it that goes to one of the foot switches ,and is the chassis ground.

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    Quote Originally Posted by Enzo View Post
    Simple test: Set up the unit as you described. Don't connect it to an amp, just the power connection. Now measure for AC voltage between the chassis of the unit and earth ground somewhere, like the center screw of a wall outlet. If you see a few volts, you have the variac backwards.

    You can find a 12vAC adaptor at Radio Shack or places like Best Buy.

    In my shop I had a collection of power adaptors, so I could always have a proper supply for anything. I always tell people to bring their supplies with them, but so many do not.
    I could only see about half a volt.

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    Quote Originally Posted by g1 View Post
    The black wire that is disconnected, is it the one in your pic that goes to the tube board bracket?
    If so, it looks like on the schematic it goes to a ground at the AC adapter jack.
    The green/yel wire lug should go to a chassis screw to ground the chassis.

    If you look at the pictures above , the blue wire is the tube ground. This black one has me baffled. No gut shots of others anywhere to be found.

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