Fixing Yamaha CA-1000 II

cellom

New Member
Hi there, this is my first post in the Yamaha forum.
http://www.audiokarma.org/forums/showthread.php?t=559253
I would like to share some pics of a small project I did lately.
Bought a CA-1000 II on ebay which was sold as a non working unit. I wanted a CA-1000 badly for quite some time and when I found this one on ebay.de, Germany (It looked okay, price was ok) I was very happy and ready for a challenge. (I am a beginner when it comes to repairing audio electronics...)

P1000345.JPG


When I first turned on the unit, there was no sign of life at all. The first thing I found was a dirty on/off switch. Cleaning it and treating it with contact spray was enough to get the switch working. (Checked it thoroughly with a multimeter before mains etc..). Amp was still dead. At least I could hear the transformer hum. But no protection relay click.

P1000354.JPG


P1000363.JPG


right channel main amp removed, this is the faulty part as it turned out. One of the fuses was blown. So I started to look for trouble here.

more pics on their way...
 
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I found the power transistors to be faulty and the fusible resistor fr602.
Replaced the transistors with ON semi MJ21194G and MJ21193G and the fusible resistor with WELWYN - ULW2-47RJA25. Not sure though if this is the best solution :scratch2:
badpart.JPG

Decided to leave the 2sc680 2sa566 alone for the moment, they seemed okay.
(I did order replacements though, at radio rotor in Amsterdam http://www.rotor.eu/en/).
New transistors in place...
P1000429.JPG

checking the idling current on both sides:
P1000453.JPG

because I changed the tr. on the left channel as well
P1000369.JPG

With these things fixed I still had a fading right channel. Even after exhaustive cleaning and treating of the pots:
P1000432.JPG

So work was continued at the switches:
P1000477.JPG

Reassembly:
P1000459.JPG

P1000462.JPG

face plate back on
P1000471.JPG

Oh, replaced the broken bulb with a LED
P1000475.JPG

Fixed for the moment :D
P1000480.JPG

test wires for idling current still there. Gonna hook em up to an arduino to warn if values start to drift. I've ordered some new multiturn trim pots because with those originals it is very hard to get the current right. Well, nothing new I guess...
 
Hah, i watched that auction as well. Was put off by the amount of rust inside.

I'm glad that the unit is getting the attention it deserves!
 
Hah, i watched that auction as well. Was put off by the amount of rust inside.

I'm glad that the unit is getting the attention it deserves!

Oh wow, cool you found this thread :) Yeah, it had suffered water damage. True, I felt kinda sorry for this machine. Once my garage is cleaned up a bit I'll try to do more of an overhaul instead of just a repair. The funny thing was, though that the rusty (left) side with the bad looking transistors was actually working (Except the power switch, besides contact spray I had to lube the mechanical part because it jammed). I really wonder what went on there...
 
You've done well, the CA-1000ii/CA-1000/CA-800 are a PITA to work on. Next step would be to complete the refurb.
Plenty of AK threads on CA-1000 refurb's. IMO the CA-1000ii is the better unit, just edging out the CA-1000, that said
the CA-800 is a great entry level amp.
 
You've done well, the CA-1000ii/CA-1000/CA-800 are a PITA to work on. Next step would be to complete the refurb.
Plenty of AK threads on CA-1000 refurb's. IMO the CA-1000ii is the better unit, just edging out the CA-1000, that said
the CA-800 is a great entry level amp.

Out of curiosity, why the « II » variant is the preferred one over the regular 1000?

Also, is the II available in 120V? The only ones I see are the Japanese 100V versions.
 
My 1000ii came from Japan, 100Vac, they were also released into Europe so a multivoltage unit may exists.
I've refurb'd a few CA-1000's and think the 1000ii is just slightly better, though it's probably my choice of components.
Guy I know up north has a CA-1000 refurb'd in Japan and it blows everything out of the water including some
separates (C-4,,,MX-1000,,,). It took a modern Luxman with extra watts and $$$$ to better it. Probably comes
down to if you got a "good one".

The circuits are much the same with minor tweeks on the tone board eg, C317, 318 upped to 4.7uf.
 
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