Yamaha C-50 No power

[Audi2014]

Soon.. will let you know.

 

[Audi2014]

Hi Avionic
Finally got a chance to check out the transformer. Had a good fuse in the unit and checked ohms between power plug terminals with unit in on position and showed infinite resistance on meter

 

[Audi2014]

Finally got a chance to check out the transformer. Had a good fuse in the unit and checked ohms between power plug terminals with unit in on position and showed infinite resistance on meter

 

[avionic]

Hi Avionic
Finally got a chance to check out the transformer. Had a good fuse in the unit and checked ohms between power plug terminals with unit in on position and showed infinite resistance on meter

Well .. That's a bummer..

 

[Audi2014]

Well .. That's a bummer..

The transformer u showed me as a replacement would work but a tight fit?

 

[avionic]

The transformer u showed me as a replacement would work but a tight fit?

Very tight fit.. Might have to trim off a little circuit board.. Unless you can find a narrower transformer with approx. 35 - 0 - 35 secondary winding. Or 70v CT.

 

[avionic]

Or find a parts unit C-50 or C-70..

 

[avionic]

Unless you want to try digging out the fuse on the bad one.

 

[Audi2014]

Very tight fit.. Might have to trim off a little circuit board.. Unless you can find a narrower transformer with approx. 35 - 0 - 35 secondary winding. Or 70v CT.

I understand

 

[Audi2014]

Unless you want to try digging out the fuse on the bad one.

What’s the process of digging out the bad fuse?

 

[Audi2014]

Very tight fit.. Might have to trim off a little circuit board.. Unless you can find a narrower transformer with approx. 35 - 0 - 35 secondary winding. Or 70v CT.

The link u sent me for the replacement transformer is only 20 dollars?

 

[Audi2014]

Unless you want to try digging out the fuse on the bad one.

Good morning
I have been busy at work and haven’t had too much time to tackle this preamp. This weekend I should have some time to take a look into this unit. I have one question for ya . if the transformer is good and the problem may be a component on the board.. in ur experience dealing with these units, where would u suggest I take readings to troubleshoot onboard components? Looking at the schematic I see some components in its path.

 

[avionic]

About the only thing else it could possibly be is wiring from the AC plug to the power transformer or the power switch. Or the wiring to and from the board mounted fuse.

 

[Audi2014]

Very tight fit.. Might have to trim off a little circuit board.. Unless you can find a narrower transformer with approx. 35 - 0 - 35 secondary winding. Or 70v CT.

Good afternoon Avionic..I just received the power transformer that you mentioned that i could use.I have so many questions. I have looked at the wiring diagram
and i am kinda confused on how this transformer can get wired up to the C-50 main board.I see 2 sets of 35 volt leads and 2 sets of 115 volt leads.

 

[avionic]

Is your mains 120 or 240 ?

 

[Audi2014]

Is your mains 120 or 240 ?

120 . My model C-50 doesn’t have the selection from 220 to 120. The previous transformer has 3 wires going into the main board and 2 wires going to the board where the main fuse is located.

 

[Sparkplug]

 

[avionic]

Private conversation started.

 

[Audi2014]

Update on the transformer issue. With the help of Avionic, I was able to troubleshoot and find out that I had a bad transformer. With his help I was able to find a suitable replacement and get it installed. Will do a test in the morning.

 

[Audi2014]

More updates on the transformer issue with the Yamaha. Everything buttoned back up after replacing the transformer and the Yamaha lives. With the help from Avionic the Yamaha has new life. Thanks again Avionic for your troubleshooting skills.