The restoration of a Yamaha CA-2000 (Japanese CA-2010)

[rottalpha]

function board.

I do not see photos of the function switches cleaning. It don't count as a full restore if you dont hit those up

edit: I should mention, if you take them apart, keep track of order and orientation. There are a few ways you can mix things up with these.

 

[Mr. Yamaha]

Those were done in an earlier stage with the horrible old method (glass fiber pen) I was afraid of being judged because of this method

I thought some things in those wafer switches could be mixed up, but when I looked better, it looks like there was nothing to mix up.





You see, the shaft is rectangular shaped, so it can fit in 2 ways. But if you turn the rotor 180 degrees to the next way, everything is in the exact same position. So here is nothing to mix up. Or did you mean the sllider switch?

 

[rottalpha]

Those were done in an earlier stage with the horrible old method (glass fiber pen) I was afraid of being judged because of this method

I thought some things in those wafer switches could be mixed up, but when I looked better, it looks like there was nothing to mix up.

View attachment 1120193

View attachment 1120195

You see, the shaft is rectangular shaped, so it can fit in 2 ways. But if you turn the rotor 180 degrees to the next way, everything is in the exact same position. So here is nothing to mix up. Or did you mean the sllider switch?

View attachment 1120196

View attachment 1120197

View attachment 1120198

View attachment 1120199

View attachment 1120200

No criticism, just encouragement and guidance, when guidance is available

Those "waffles" are not always identical, so the front to rear order could be relevant.
Then they are not all turning 360, not allways.
Then what if you install one on 180 deg out of alignment with the others.
When you have just two or three waffles to worry about, is acceptable, albeit, it sucks if you have to realign, rearrange them after you put them back together.
Those selector switches can have well more than a couple of waffles. That is when things can get interesting

 

[Oilmaster]

By others faults the wise correct their own

Credits to Mr. Yamaha for not being shy about it.

 

[Mr. Yamaha]

Had some time to finish the tone control board. All switches were taken off the board and wer completely dismantled, cleaned and preserved. Most components were replaced: all transistors and fusible resistors. Most mylars are replaced by PP caps. It was a tight fit between the switches.

While working on the last switch this horrible event took place during assembling (too reckless with the pliers):



And ofcourse when bending back (and yes, it's an active pin):





But I guess I was very lucky. Two switches are exactly the same:



To the left the position of the damaged switch, to the right the identical switch. Fortunately on that switch the pin is not active, so I can swap the switches :

 

[Oldsansui441]

Nice save, that was very lucky indeed.

 

[Mr. Yamaha]

Here some pictures of the board itself:

Before (without switches):



After:

 

[Mr. Yamaha]

And some pictures of the switches:

 

[Bratwurst7s]

Beautiful work. Very precise. Love it!

Cheers,
James

 

[Oldsansui441]

Yes this is one very lucky Yamaha, great work.

 

[Mr. Yamaha]

Already finished the coupler board. Forgot to post pictures Pretty straight forward. Only two axial electrolytics and two switches to clean.

Those RCA's are completely corroded, beyond repair. Haven't found better ones yet. But I don't think I will ever use them.

Before:





After:







Switches:

 

[rottalpha]

Already finished the coupler board

would you please measure the (on center) distance between those switches screws? screw center to screw center....

 

[avionic]

You didn't polish the RCA jacks.......

 

[Mr. Yamaha]

would you please measure the (on center) distance between those switches screws? screw center to screw center....

20mm.

You didn't polish the RCA jacks.......

 

[rottalpha]

20mm.

TY Sir!

 

[rottalpha]

20mm.

I was gonna say, you missed a spot

while the chorrosion spots might not come out with polishing compund only, I have good hunch they will come out with a dremmel and a soft metal wire-wheel ...even a SS wire-wheel might work.

 

[Mr. Yamaha]

I was gonna say, you missed a spot

while the chorrosion spots might not come out with polishing compund only, I have good hunch they will come out with a dremmel and a soft metal wire-wheel ...even a SS wire-wheel might work.

Not really, the corrosion is all through the nickel on the copper. Already found that out. So when I proceed, I'll end up with bare copper rca's

 

[Mr. Yamaha]

I finally finished the driver boards yesterday, the last two boards of this project. All components were replaced except the carbon resistors.

I was able to source NOS Toshiba 2SA1306Y/2SC3298Y pairs which I intended to use as drivers and NOS Hitachi 2SB649AC/2SD669AC (TO-126) which I intended use for the VAS.

But, when working on the first driver board I discovered that the housing collector of the old was transistors was used (through the bolt) instead of the collector pin. And the Toshiba's do have an all plastic housing... So much for the Toshiba's Fortunately the Hitachi's did have collector in the TO-126 housing, so I ended up using them also for the driver stages.

Before:



After:

 

[Oldsansui441]

Very neat work Mr. Yamaha, as always. I like that little pcb vice of yours.

 

[Mr. Yamaha]

Had some time to assemble everything this weekend. I thought I was done with the switches, but there was one left for me in the chassis: the speaker selector switch

It was completely taken apart, cleaned and preserved:







Everything assembled, wiring checked 5 times (transformer needs new paint, on the to-do list):



Then it was time for first power up, with a DBT of course. And then a bright DBT bulb. Oops!

Time to trouble shoot (thanks Oilmaster for some useful tips). I started to pull fuses to determine where the problem was.

Ingoing voltage OK, outgoing voltages from transformer OK, outgoing DC voltages PSU board OK. Then I found 2 problems: -B2 rail not OK and +B1 rail not OK. Both showed a short circuit directly to E.

I was very sure I had all components in correct, NPN / PNP was correct, pinouts correct (checked measured everything 5 times). So, what can it be?

Then I started measuring where the short circuits were caused and I was able to track them down. And then I learned everything about mini solder bridges between a solder pad and a neighbor track I had never experienced them like this. The tracks look covered with green PCB stuff, but when you look with a magnifier, you can see bare copper on the side of some tracks and it's very crowded on these boards.

I found one solder bridge on the right driver board and one on the tone control board. I removed them and resoldered the pads.





And after that I reassembled everything and powered it on with DBT and the bulb was dim this time. Then without DBT and then a nice relay clang

So that was solved, right? Now some signal to input and test with headphones. With a signal in, I had just one meter working and the protection relay started to click off and on for a few times.

And then: white smoke came out (a lot) Powered it off quickly and started to investigate what caused the smoke.

On the tone control board:





Two toasted Vishay Dale RN's

Started measuring again and found a solder bridge like the ones before between the right channel and E. Most likely created when connecting the volume pot board to the tone control board with three jumpers. Solder bridge already removed, but you can see the silverish side of the track next to the solder pad:



Set the bias and DC offset and after that everything was working and I hooked it up to my DAC and the NS-1000M's.

Making sweet music