Yamaha CA-1010 recap

Hi all,

Just wanted to share some pics of my refurbishment of the power supply board of a Yamaha CA-1010. It had some popping noises which are now gone. It had some 120 Hz hum before and that is gone too. The sound has become more spacious and with a better fundament in the bass. More to come on the recapping of various other parts.

Disclaimer: I am a total rookie for electronics repair and refurbishment, only use this information for ideas and do not use it as recommendation!

First pic: before recapping. (Note: some caps are not original but were changed in a repair previously.)



I changed all capacitors to Panasonic FM or else FC, or SU (bipolar). New rectifier diodes (the 4 MUR420 where a little to big, causing a little kludge work to largen the holes to fit it). New resistors near the lower heatsink, since they looked burned. New relay. New output inductors and resistors, since they are in the signal path and the new inductors can take 12A and have only 0.005 Ohms DC resistance.



Here is a picture of the new relay in front and the old relay. You can see the copper on the old relay looks almost white compared to the new relay.



Below some of the old capacitors. They look burned but will probably work ok. The brown stuff is not leaking electrolyte but glue, said to get conductive over time. Note that excessive glue was already removed before taking this picture.



But I'd guess the cap on the right below has ceased it's flawless operation:



Turned the device on and... Fault! Music is playing, but B2 was only -15 V instead of -30.8 V. Boy, transistor TR409 sure has a tough time on startup. I replaced it before with 2SA970 (after a zener diode fault) but forgot to replace TR408 which should be complementary... So I went with 2SA970/2SC2240 which have a bit lower fT but 2 times higher current handling, still only 100 mA. And changed 3 diodes to the sturdier 4007 type. I also replaced TR410/TR411 with TIP41C/TIP42C and thought it better to have some space between their heatsinks and the pcb, which is mounted upside down in the device. So I put a plastic washer in between. You can see the heatsink floating above the pcb:



I should still change TR412 to C2240 (since I changed TR413 too) and add heatsink glue to TR410/TR411.

Great post, thanks for taking the time to document the details.
I have been looking at my CA1010 and wondering what results a recap might have. The boards in your pix look reasonably easy to work with. I am not having any sound issues as yet, but 30 year old caps must be reaching their outer limits of endurance. the CA1010 is one sweet amp, and certainly deserves the attention!

add heatsink glue

Click to expand...

Its not glue.Its thermal compound ie. silicon and zinc oxide.

Strange square wave behavoir

Thanks Avionic, that is what I meant.
The popping sound did turn back for a short while, then disappeared, so it must come from somewhere else. At least I now know it's not a power supply issue.

I took PC scope measurements and THD (unloaded) seemed to comply with the 8 Ohms spec, both for class AB and class A. Very nice. This was without load, I need to fix dummy loads.

But I was very shocked by the square wave behavoir (see pic). It is not putting out anything like square waves! There seems to be a time-constant after which voltage drops, i.e. independent of frequency. And, with at least one frequency this also happened with a real loudspeaker as load.

Can someone help me with this? How can I correct it, should I lower the feedback capacitance C310? The reason I would like to correct it is, I want to try some modifications and I don't think they're worth the trouble if I can't fix this.

Update: Oops! Measured the PC scope itself and that is the device to blame. So I will need to eliminate this RC voltage droop effect in the measuring device. The amplifier might be doing ok, I don't have an oscilloscope available at the moment to check.

Ok, recap is complete now! Before you read on, let me remind you I am an amateur so take this with a pinch of salt. Actually, some feedback about what I did, the do's and dont's would be appreciated.

After the power supply (previous post) I did the pre amp board. It had some tantalum capacitors (4 lytics already removed):



And some electrolitics. Note, there are two places on the board with no capacitors installed, maybe these places were used on the CA-2010?



The final result:



Trace side of board was cleaned with Windex and then 96% ethanol. Windex left some residue on the board, be sure to rinse if you use it. The board was pretty dirty before.



The preamp installed, the Elna Silmic II's are a little taller than the originals but fit nicely.



Three notes for the previous picture: the six fusibles were checked to be within 2% of the schematic values and the "double" diodes D101/102 where checked, and C127 to C130 didn't have to be changed to polypropylene Panasonic ECQ-B, but they where affordable and fitted so why not.

Then the meter board. This was tricky, the manual said C505/506 = 100uF/6.3V and and C509/510 = 47uF/35V but in reality it was 33 uF and 50 V respectively. I replaced with 47uF/35V and 47uF/50V. (And C501/502 was 3.3 uF and was replaced by 4.7 uF, it is not so critical.) Before, with the metal shield still attached:



After:



Then I replaced the only 4 elcaps on the tone board. I didn't check the fusible resistors though.

Then changed the display lighting to LED's. I tried half rectified with a single diode and 180 uF cap but that showed some 50 Hz flickering. So I let it tap power from the DC side of diode D401, so fully rectified. That stopped the flickering, unfortunately the speaker protection relay now needs a long time, about 20 minutes, to close when powering up "cold". I haven't found out what is the issue yet. :scratch2:

Listening session to phono showed me the phono stage sounded less warm than before but a lot more dynamic. The solo violin lost some of its body but the orchestral accompaniment was more vivid, so to say... A result I am very happy with.

Then I attacked the two big cans, they required some time to desolder. Here are the old (18000uF) and new (22000uF) cans, with in front a 2.7 KOhm bleeder resistor to prevent "shocks and sparks". You can see the cans are "family".



The screw terminals of the new cans are nice, unfortunately they have to be installed with the terminals up, since the gray vent is at the terminal side. So I ran wires from the bridge to the terminals and laid out a wiring scheme. It uses star ground with seperate ground point for phones and LP ground. See picture below.



New supply wiring was installed, and new internal speaker wire, bypassing the old speaker switch for channel B. Also 2.2 uF polyester bypasses on the large cans. The internal speaker wire runs to some new binding posts. Actually the new binding posts were attached to the old pieces of support plastic by some sawing and reinforcing the plastic with epoxy glue.

I put everything together. A little more hum than after the recap of the power supply board. But it's only heard when putting the ear on the tweeter, acceptable for now IMHO. It has become a little more sensitive to other appliances turning on or off. I have to hear more, but preliminary conclusion is it sounds mighty fine.

Note: I haven't changed anything to the amplifier module itself! In that sense I haven't changed the sound signature (or lack thereof) of this amplifier, but merely tried to provide the best conditions for reliable operation. The amplfier boards still contain four 1 uF elcaps that need to be changed.

pradigmshift said:

Here is a picture of the new relay in front and the old relay. You can see the copper on the old relay looks almost white compared to the new relay.

Click to expand...

I see you replaced the original Panasonic relay with a Tyco/Potter & Brumfeld. I did the same thing with mine... but it only lasted three years. I replaced my failing P&B with an Omron this past summer.

Very clean work.

Tom

Looks great man! I need to do the same with my CA-2010.....

Thank you!

OvenMaster said:

I see you replaced the original Panasonic relay with a Tyco/Potter & Brumfeld. I did the same thing with mine... but it only lasted three years. I replaced my failing P&B with an Omron this past summer.

Click to expand...

Correct. That is very short! I hope mine will last longer. It depends on the speed the 22000 uF capacitors charge from switching class A to AB. The current should not exceed 15 A, the current the relay is rated for. Corresponding voltage transients could be checked with a scope. The old relay gave sparks on power up, in spite of the capacitors C601-C604.

The popping noises I noted in post #1 returned. I finally found the perpetrator, it's the main/pre coupler switch at the back. It was cured by applying some tuner spray. If the problem returns I will dismantle the switch and remove some carbon. So if you have a similar unit which starts to make popping noises spray this switch first.

The speaker relay now works fine, it clicks after the regular 4 seconds (post #6). I don't know why this has changed from 20 minutes but it's good that it did.

pradigmshift said:

I also replaced TR410/TR411 with TIP41C/TIP42C and thought it better to have some space between their heatsinks and the pcb, which is mounted upside down in the device. So I put a plastic washer in between. You can see the heatsink floating above the pcb:

Click to expand...

The screw tends to loosen up so I will put a rubber or other elastic washer adjecent the nut, on the trace side of the PCB.

hello all, its great to see all this work being done on this amp. i am going to change the relay on the psu board and was thinking of changing the diode next to it i was wondering if anybody knows of an equivalent to this diode. i think it is a signal diode. thanks to you all.Sean

You mean diode D404 (as mentioned in the manual)? I assume it controls the current of the relay coil to go 1 way only, so not signal path related. I don't think it needs replacement.

This is only my guess though!

And thanks, the amp is currently running and sounding great!

hi again, no its D601. i've changed the two big psu caps.and the relay and was going to change D601 as well before i move onto the other boards. thanks again for your expert knowledge

Yes D601 on the electrolytic capacitor board. It has the same function as D404 on the power supply board and is also type 1S1885. Also, not necessary to replace. If you would want to replace anyway a 1N4007 would do. Also 1N4003 to 1N4006 would do. I don't think the smaller surge current rating (30 vs 50) would pose a problem here.

thank you very much. best regards Sean

I also have CA-1000 III, identical to CA-1010. Im planning to re-cap it this week, questions on the capacitors..

1) Original 1000uf 6.3v on the amp side are as about the size of my middle finger (diameter). The available here are so little about the size of a pencil, so small compare to the original ones about 1/4 of it. And also the 100uf 6.3v. They have the same value anyway, would there be any problem with these.

2) The original xxuf 80V are not available in our area, is it okey to replace those xxuf/80v with xxuf/100volts?

Both replacements are good looking at voltages only. My four 1000uF/6.3V replacements are a little bigger than the original because I took Elna Silmic II caps for these. (For the rest I used Panasonic FM, otherwise Panasonic FC.)

I have not done the main amp board yet, so I'm wondering if it would be ok to replace the 1uF/80V with 10uF/80V lytics? It should give some better rail regulation but might give other problems.

Id like to try 10uF/80V lytics but we dont have this values. Only 100V lytics are available. Im want to replace 1uf/80v with 1uf/100v would there be any problems??

jagkarma said:

Id like to try 10uF/80V lytics but we dont have this values. Only 100V lytics are available. Im want to replace 1uf/80v with 1uf/100v would there be any problems??

Click to expand...

No problem..