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SVT 7Pro Rebooting - Mainboard Replacement?

#63
baxter_x said:
Ok, then he must service it....
I was saying this based on the fact the amp was repaired by a non tech guy.
Click to expand...
If the amp wasn't really fixed, that's a different thing, but there's a history that seems to repeat itself...
 
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#64
Shlabotnik said:
I want to let everyone know that this problem came back after I had replaced the board with a rev H0. It was fine for about 3 years and then the problem came back. So, I figured... "I'll replace the board one more time and then sell this thing."
So the new (2nd replacement) board came in today, after an 8 month backorder. I installed it and now I've got a new issue that perhaps someone might have some advice on?
With the new board installed it will not turn on at all. Well, let me clarify "at all". The fan doesn't turn on, the power LED doesn't come on and it doesn't output sound.
However, I can see that power is going to the preamp because the tube is glowing lightly as it should be. Also, when I hit the "mute" switch (I tried pushing all of them) the peak/mute LED comes on.
I hate to put more money into this and I'm kind of disgusted with the whole thing but I don't know wether to smash it with a sledgehammer or, perhaps put yet more $ into it by bringing it to a tech. Both options are tempting.
Any ideas? Thanks!!!
Click to expand...

Thanks for posting that follow-up to your original thread. I am a repair facility in Atlanta and have replaced the boards in several 7PROs (all with REV F boards.) . I just received a REV H01 board from Yamaha and am having a mostly same problem. With the unit plugged in but the power switch off part of the power supply is on and the unit exhibits the same symptom: MUTE light is on and if you have the cover off you can see the tube filaments lit up. When the power switch is ON the amp works normally but when switched off I get the same MUTE light on condition. (I have been mulling over possible solutions to this and one just occurred to me: jumper the connectors the power switch is currently connected to and rewire the power switch to completely cut off the AC to the unit. I'll ponder this as I await Yamaha's response.) The only way to truly power down the amp is to unplug it. I have emailed Yamaha to get technical assistance on this. I will post what they have to say about this.
 
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#65
5stringfretless said:
Thanks for posting that follow-up to your original thread. I am a repair facility in Atlanta and have replaced the boards in several 7PROs (all with REV F boards.) . I just received a REV H01 board from Yamaha and am having a mostly same problem. With the unit plugged in but the power switch off part of the power supply is on and the unit exhibits the same symptom: MUTE light is on and if you have the cover off you can see the tube filaments lit up. When the power switch is ON the amp works normally but when switched off I get the same MUTE light on condition. (I have been mulling over possible solutions to this and one just occurred to me: jumper the connectors the power switch is currently connected to and rewire the power switch to completely cut off the AC to the unit. I'll ponder this as I await Yamaha's response.) The only way to truly power down the amp is to unplug it. I have emailed Yamaha to get technical assistance on this. I will post what they have to say about this.
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Wow that's amazing info, thank you so much for telling me this! I ended up bring it into a shop in NH to have it looked at and I am going to send them everything you just wrote here as I have not yet heard from them as they are a bit backed up. I will definitely update you if I hear back anything from them before I hear from you again. Let's be sure to keep in touch!!!! Wow.
 
#66
5stringfretless said:
Thanks for posting that follow-up to your original thread. I am a repair facility in Atlanta and have replaced the boards in several 7PROs (all with REV F boards.) . I just received a REV H01 board from Yamaha and am having a mostly same problem. With the unit plugged in but the power switch off part of the power supply is on and the unit exhibits the same symptom: MUTE light is on and if you have the cover off you can see the tube filaments lit up. When the power switch is ON the amp works normally but when switched off I get the same MUTE light on condition. (I have been mulling over possible solutions to this and one just occurred to me: jumper the connectors the power switch is currently connected to and rewire the power switch to completely cut off the AC to the unit. I'll ponder this as I await Yamaha's response.) The only way to truly power down the amp is to unplug it. I have emailed Yamaha to get technical assistance on this. I will post what they have to say about this.
Click to expand...
Wait to hear back from Yamaha. Rewiring the primary circuit like you describe would invalidate any safety certification that the amp currently has (UL/IEC 62368-1), so if there was an issue down the road you could be dragged into legal issues. As a service facility, you should be aware of this. You should also update your forum member status to commercial user and display your affiliation.
 
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