Yamaha C-50 No power

[Audi2014]

Hello everyone
Picked up a Yamaha C-50 Preamplifier from a friend. Unit has no power when trying to turn on. Checked fuse and it is intact. Need a link for a service manual to try to troubleshoot this unit. Anyone who has had this problem I would love to hear from you
Thanks

 

[avionic]

Ohm out the primary of the power transformer.. The is a fuse within the transformer.

 

[avionic]

Need a link for a service manual to try to troubleshoot this unit.

Download it from HFE

 

[avionic]

 

[Audi2014]

Download it from HFE

Thanks for the info about a service manual. I read ur comment about ohming out the primary. Is this fuse accessible?

 

[avionic]

Is this fuse accessible?

Probably not very easy to get to. Have to see if the transformer is potted inside that metal cover.

 

[Audi2014]

Probably not very easy to get to. Have to see if the transformer is potted inside that metal cover.

Good evening Avonic
Is this an issue with this model preamplifier? What causes this problem to occur with these units?

 

[avionic]

Lightning, shorted bridged rectifier, some one installing the wrong sized fuse .. plugging into 220v to name a couple.

 

[avionic]

Check it by measuring the resistance across the power plug with the power switch in the on position and a good fuse installed.

 

[avionic]

If needed this might be used as a replacement -- be a tight fit..

AS-0528 - 50VA 28V Transformer

Toroidal transformers and power supplies

www.antekinc.com

 

[Audi2014]

Check it by measuring the resistance across the power plug with the power switch in the on position and a good fuse installed.

Will do.Thanks for the info for a new transformer.

 

[Audi2014]

Will do.Thanks for the info about the transformer. Will do an ohm check across the plug. If a blown fuse would I get a open reading?

 

[avionic]

A C-70 transformer would also work.

 

[avionic]

What type of reading would I see if the fuse has blown in the transformer?

open circuit -- infinite resistance

 

[Audi2014]

Will do.Thanks for the info about the transformer. Will do an ohm check across the plug. If a blown fuse would I get a open reading?

 

[avionic]

12 - 15 Ω if it is good..

 

[avionic]

If a blown fuse would I get a open reading?

open circuit -- infinite resistance

 

[Audi2014]

12 - 15 Ω if it is good..

Thank you.

 

[avionic]

Any luck ?

 

[Audi2014]

Any luck