Yamaha P-45: USB not working?

[BKN4691]

I recently purchased a used Yamaha P-45. Everything works fine except the USB. When I plug it into a computer and turn it on, the computers don't even recognize that a new device has been connected. I've tried various cables (old, new, short, long, etc.) and checked all the accompanying literature I could find (Owner's Manual, Computer-related operations, MIDI Basics) and didn't find anything. My other keyboards connect fine to these computers.

After purchasing it I had to open it up to extract a penny that had been dropped inside and was rattling around. I suppose it could have shorted something out. I don't see any physical damage to the boards or connectors.

I only paid $150 for it and everything else works fine, so not the end of the world if the USB doesn't work.

BTW, this thing has 58(!) screws holding it together!

Any thoughts?

Thanks

 

[happyrat1]

"Any thoughts?"

Give it to the youngest toddler in the family and let his inner Mozart voice speak

 

[happyrat1]

And L20 on the 2nd photo probably burned a fusible link,

 

[BKN4691]

And L20 on the 2nd photo probably burned a fusible link,

Thanks Garry. I'll check that.

 

[happyrat1]

Looks like it may have been a zener diode.

 

[Bouncingogre]

Above DM on your photo, you've got a blown capacitor.
Maybe?

 

[Biggles]

Yep, blown capacitor.

Return it For a refund.

 

[BKN4691]

Thanks all.

 

[happyrat1]

It's not a cap. it's probably a diode

 

[Biggles]

Same component body

 

[happyrat1]

Ah, we were talking about different images. please post which image you refer to in the future.

 

[Biggles]

Ah, we were talking about different images. please post which image you refer to in the future.

Fourth image down, where it looks like dielectric material has leaked.

As it is with the apparent burnt out linkage there seems to be multiple issues.

Best to return it.

 

[BKN4691]

Wow, I completely missed that. I'm great with mechanical, not so much with electronics. I'm not planning to return it. I bought it locally off Facebook marketplace and I seriously doubt the person had any idea as it works fine otherwise. I'll either see if I can repair it as a learning experience, or just use it as is until it dies.

 

[Gourockian]

And L20 on the 2nd photo probably burned a fusible link,

'L***' on a PCB would normally indicate an inductor. It doesn't look much different from the two on the third picture.

One thing I've found to be problematic is dirty contacts on the USB socket. Light sanding with a trimmed down emory/emery board for finger nails usually helps.

 

[happyrat1]

There was visible arcing damage on the USB port itself. Check the contacts. USB specs include a low power, current limited source which could easily have been shorted by the inserted coin.

The component may have been a fusible LINK. Another item that begins with "L"

 

[happyrat1]

Hell. Just stick a ohmmeter across the terminals. Check the "Link" for continuity and the USB for shorts.

 

[happyrat1]

https://www.youtube.com/results?search_query=how+to+fix+a+shorted+USB+port

 

[Gourockian]

There was visible arcing damage on the USB port itself. Check the contacts. USB specs include a low power, current limited source which could easily have been shorted by the inserted coin.

The component may have been a fusible LINK. Another item that begins with "L"

Your eyesight is definitely better than mine as I can't see the arcing damage you mention.

Any fusible links that I have come across were always marked FL, as seen in this picture. As you probably know, regular links (jumpers) are numbered J***, as shown in the OP's third picture.

Just to satisfy my own curiosity, I downloaded the P-45 Service Manual and it confirms that it is indeed an inductor, or coil as they call it. It is actually numbered L201 but the last digit is not clear in the OP's picture. It could easily be checked for continuity if there is doubt that it is damaged.

I have to say that in all my years working with PCB's, not just keyboards, I've never seen an inductor quite like those. Yamaha must have bought a job lot going cheap.

 

[BKN4691]

Hopefully I'll have some time this weekend to dig into it a little further.

 

[Gourockian]

Hopefully I'll have some time this weekend to dig into it a little further.

If you don't already have a copy, you can download the service manual here.

https://elektrotanya.com/yamaha_p-115b_p-115wh_p-45b.pdf/download.html