• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

CA-810... with some pics

Yamaha CA-810

Cleaning faceplate, knobs before reassembling boards for tests...

4n7f.jpg


i64o.jpg


6xzf.jpg
 
Yamaha CA-810

Look at this... that little cable that links the Volume to the Loudness boards...

0e8o.jpg


nhol.jpg


A bit better and less stressed...

sbh7.jpg
 
Yamaha CA-810

Let's check the idling current and the "mid-potential" (DC Offset) thing that confused many people already, including myself when started reading this...

6r20.jpg


So, bias has to be 20mV (+/-5mV) and that's pretty easy...

71vn.jpg


The mid-potential has only to be CONFIRMED that the LO and RO voltages of main circuit board are both zero volt.

Touché!

xs0u.jpg


Anybody knows what VR801 is for? :scratch2:

zcop.jpg


VR402 seen from lateral part...:rolleyes:

ycc7.jpg
 
Last edited:
Yamaha CA-810

So...

At least the CA-810 is alive again. I put the old 12,000uF 56V big caps to test it briefly and I have music! The input selector works fine... :music:

I'm waiting for the two new 15,000uF 63V for a real test...

There are a few things like the red LED (Power On) is still not giving any V... :headscrat

rvlm.jpg


5u3a.jpg
 
Hi Karl, great renovation, with great pictures and a great result.

Thanks a lot for sharing :thmbsp: :thmbsp:
 
dksp said:
Hi Karl, great renovation, with great pictures and a great result.

Thanks a lot for sharing :thmbsp: :thmbsp:
Click to expand...
Thanks! :thmbsp: It's an ongoing project. I'll fix the LEDs (greens and red one)...

I was testing it before and the sound is fantastic! I'm now waiting for the big caps.

I wanted to buy the F&T ones, but they went sold out...

hf7p.jpg


39cross said:
MC amp? :scratch2:

Thanks for the grand tour, it was wonderful.

How did you make out with the wire wraps?
Click to expand...

I found further info here about that VR801. Seems to regulate the 25V (+/-) to the input board via the gray and yellow wires. I took measurement and it is under good value...

npao.jpg


For the wire wraps, a round nose pliers and a lot of patience did that work. :thmbsp:
 
Last edited:
Nice pictures! Running a 810 through the bedroom system this afternoon. Nice sounding model replaced a Marantz 2245 that needed a switch cleaned. Makes those 2AX's sound pretty good. Not as much bass as the Marantz but still nice.

Mine was a pile of parts when it came home. They had taken the meters apart and left hanging along with the other half still on the front panel. Trying to replace the lamps be my guess. Had to hold my breath and straighten one of the needles and reattach everything. Bag O parts and all.

But all good now.

Thanks for the thread. Lot of good information.


Barney
 
Yamaha CA-810

Thank you, folks.

The amp is doing fine. Listening to it right now, Jean-Luc Ponty.

If I ever have to work on another CA-810 I will do it differently.

Later I fixed the red LED (power on) and replaced the resistors for the VU green LEDs.

I'm still thinking if replace the A844 and other TRs, although I have no hums or hisses.

I really love this amp. The AX-900 is a bit punchier, maybe the new caps there are of better quality (Panas FC/FM/FR), but the CA-810 is a good amp, too.

hkzc.jpg


ghau.jpg
 
awesomeeeeeeeeeeeeeeeee work.
Thank you very much for the efforts documented your work.
I will need this, since may be i will get into the mood to do somehting with my CA-810.
I bought a CA-810 some days ago as i has always been on my wishlist. I have not even opened the cover, since it works fine so far
One question to the experienced 810 owner ... i have to crank up the volume knob quite a bit to get comparable volume with other amps ... is that somehting yamaha specific ... ?
TIA

Khai
 
Khai said:
One question to the experienced 810 owner ... i have to crank up the volume knob quite a bit to get comparable volume with other amps ... is that something Yamaha specific ... ?
TIA

Khai
Click to expand...

Yamaha calls this effect "Natural Sound" and you will get use to it. Mess with the controls especially the loudness. But yes it is a more neutral reproduction of sound.


Barney
 
Thanks for the CA-810 rebuild lesson. I have just bought one and haven't done anything with it yet. I'm hoping to clean it up some and see if it works this weekend. I did plug it in and see the meters aren't lighting up, seems like a lot of CA-810 have that problem and the owners change them out for the LED lamps.
 
Hello Kard Verg, your pictures are all gone or is it something with my PC? I only see the two above on this page
 
Oh! Imageshack was changing policy I guess.

I have all of them saved. They seem to be back. Thay are +100 pictures for this thread! :sigh:
 
Karl:

I just spent about an hour going through this entire thread again. I really thank you for doing such a great job posting the "In-Progress" shots of your rebuild.

I have designed, refurbished and repaired Electronic Receivers, Transmitters, and Amplifiers since I was a young teen and first got my Amateur Radio license, but I have rarely seen such a complete and exacting refurbish job. You really went above and beyond. And that amp deserved it. You know my position on the mighty CA-810 from my previous posts. I have other Amplifiers, some with big names, but the CA-810 remains my all time favorite.

Many thanks.

Aloha and Mahalo:

-Billy
 
You must log in or register to reply here.
Back
Top Bottom