Man vs. Beast: CA-2010 restoration project

im kind of stressed about using these Chinese made caps in the function board which deals with the actual audio signal but im gonna measure each with the ESR measurement thingy and hope for the best
 
The Sherwood was my first introduction to tantalums, no numbers on them had to figure out what they were they are colorful. Also the old CDC "flying saucer" transistors too.
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The two top ones look very similar to 1µf/35v . In a Yamaha CA-400 caused real bad popping in the tone control switches They turned into 300 Ω resistors.
 
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Most of the tantalums in the Sherwood and Kenwood tended to read in the 15-16 ohm range. Don't know the deal with the two coupling caps at the front of the amp cards in the Sherwood, those two tantalums registered as diodes only ones so far to do that. The old solid aluminum ones also tend to become little resistors too. Some brands used them instead of the tantalums.

That is bad. My cheap $22 amazon tester is reading about 2 uF on the top ones with ESR over 8 ohms. Wonder who the supplier of the multicolored ones was. I gather the color combination is supposed to tell the value. The Kenwood ones were solid blue with the value and + symbol in white print.
 
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Dadbeh,

One of the reasons I like the Kemet R82s is at 3.3 uF or below fitment is almost never a problem. Those big ones you have are like using the Panasonic ECG where they only make most of them in the higher voltages these days making them huge. Here is a pair of 1 uF 63V R82s with a penny:
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so most caps and diodes are coming from mouser by tomorrow. i did a poor job of choosing the right assortment of ceramic caps and the one that i recieved does not have 220 and 330 pico farad in it, but the next kit from china will have any value that might come up in these amps so waiting on that. only two 47 ceramic caps have been replaced so far. all the fuse resistors measure just right, and for the carbon resistors and the transistors im gonna trust in jesus :D :D :D

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im debating if i should desolder the selector knobs to clean, it looks like a lot of work and when i was testing none of them sounded scratchy. i dont know, i want to be thorough but i dont want to be overwhelmed again. it is not a nice feeling.

as you can see i am doing all the work with wires attached to the unit and sitting on the floor hunched over the board. shoulder pain is guaranteed to arrive soon.

what are those black blocks that are branded yamaha? do they have to do with the RIAA curves for the phono? some kind of DSP?
 
Probably some sort of input mosfet or a matched pair of transistors in a single physical package. My Denon has one similar.
 
Looking at the schematic those are apparently IC101 and IC102 which seem to be involved with the phono equalization. Probably custom made part like a couple of chips were in my Scott. The pictures I come up with for the 2SK100 they look like the two longer thin black guys to the left of the switches.

I have never had to desolder the switches. I can tell you from recently dealing with the function selector switch on a Technics SA-5470, similar in design to the top one, it was distorting with the AUX input had to figure out how to get it clean. Figured out when you click in there is a piece inside that slides forward and back. When it is forward shoot cleaner in the back big hole on top. Turn it the other way so the piece slides to the back then flush through the front hole. Work it back and forth. Doing that approach with cleaner and lubricant finally fixed the random distortion issue.

You just have to work at it and figure out where the holes are and how to get the cleaner inside on the contact surfaces where it needs to go. Takes a bit of practice.

Usually leave the resistors and transistors alone unless it is not working right. When it is clear you have a problem then have to do some detective work.

I try not to have to undo wires unless replacing something or absolutely have to to get to something. I have had to de-solder a few wires in units to get it where I could turn a board to recap it. Not very often fortunately.
 
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Looking at the schematic those are apparently IC101 and IC102 which seem to be involved with the phono equalization. Probably custom made part like a couple of chips were in my Scott. The pictures I come up with for the 2SK100 they look like the two longer thin black guys to the left of the switches.
I'm thinking proprietary op amplifiers. ie " chip amps " For the MC pre-amplifier.
 
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i could use some direction on how to take outthe power supply board (the board with the 22kmf caps on it.)
 
i could use some direction on how to take outthe power supply board (the board with the 22kmf caps on it.)
I'm at work right now. When I get home to my shop this afternoon I can be a little more of assistance.
 
the wires that bring the AC in from the white fuses are tied in a knot and then soldered so i can get them off :(
 
Some advice: take out all boards, disconnect the wires, label them and work on the separate boards on the bench.
 
Some advice: take out all boards, disconnect the wires, label them and work on the separate boards on the bench.
ok. i will do that. at first i was trying to recap without taking the face plate completely out and the wires all out. but i see that it is not really possible.
so now i am going all out. I cut the ground wires connected to the power supply board because i couldn't desolder.

now i am having a little bit difficulty taking the front top panel off. the 3 selectors that are connected to those arms behind them have a hex type screw in them that does not let me take the board behind the face off. i hope that made sense.
 
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the wires that bring the AC in from the white fuses are tied in a knot and then soldered so i can get them off :(
I didn't find it that difficult to remove that board, you just need to draw a diagram, or take a few pictures, then de-solder the wires then the board can be un-screwed and removed.
Might as well replace that relay while you're in there too, its the ClassA switching relay...
 
ok. i will do that. at first i was trying to recap without taking the face plate completely out and the wires all out. but i see that it is not really possible.
so now i am going all out. I cut the ground wires connected to the power supply board because i couldn't desolder.

now i am having a little bit difficulty taking the front top panel off. the 3 selectors that are connected to those arms behind them have a hex type screw in them that does not let me take the board behind the face off. i hope that made sense.
Are you talking about the panel that covers that board? I only did one of these the other day and I am not sure what part you're talking about?
Can you post a picture?
 
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3 selectors that are connected to those arms behind them have a hex type screw in them
Just loosen the set screws in the knobs either 1.5mm or 2mm set screws. Remove the paddle knobs.Then slide the shaft extenders off the plastic u-joints. Don't need to disassemble the front chassis panel any further.
 
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To remove the front panel - desolder the 4 power meter wires at the circuit board. Not from the meters.
 
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