Yamaha CA-2010 meter driver PM-02 / IG00136 help needed

[The BXX's]

I just had the opportunity to buy this great Yamaha amp CA-2010 from a guy who said that something had blown and all went dead. Furthermore, he told me that the meters had stopped working some years ago. Cosmetically, it is almost perfect, so I thought that it was worth the 100 bucks he asked and took it with me.

At home, I disassembled the amp to check what might be broken or defective, but so far, I found nothing. All fuses are ok, all output transistors test ok, the rectifier diodes as well as the filter caps also seem to be all right. I'm going to clean it and switch it on behind a lamp to see if the reported problem is more complicated or simply was some kind of the guy's confusion.

However, regarding the meters, I'm confronted with the worst case scenario. Someone had the bright idea to remove the proprietary Yamaha PM-02 resp. IG 00136 meter driver. It is simply entirely missing. Not there anymore and most certainly carelessly thrown away like a burned out lightbulb. Searches on the internet and especially in Ebay didn't show any results for spare parts, it seems to be impossible to find a replacement. My only remaining hope right now is to rebuild it. In a Japanese Yahoo blog, I found a thread from a guy who opened the case of the driver to repair its internals:

One can see that only quite ordinary parts are used inside the driver, and the Japanese guy seems to have managed to repair his defective item. Not surprising, given that all visible part should still be easily available today.

Unfortunately, I'm not capable to reconstruct the driver from the image, and worst of all, there are not the slightest details contained on it in the CA-2010's service manual.

So my question is: Does anybody happen to have more detailed information about it? Perhaps even the schematics? I checked the ones of the meter board that's inside the CA-1010, but there are some major differences around it that most likely make it impossible to just copy that one.

Thanks in advance for any hints!
Thomas

 

[clinic-audio]

Hello Thomas

So my question is: Does anybody happen to have more detailed information about it ? Maybe , I have to look

Perhaps even the schematics ? no , YAMAHA did not supply such information

I checked the ones of the meter board that's inside the CA-1010, but there are some major differences yes , this is completely different schematic

that most likely make it impossible to just copy that one. no , but very costly , yes !

 

[willyrover]

$100 ?? Hell yeah.

 

[mbz]

Fairly sure it does not affect sound quality. For $100- I could easily live with no meters. Better off to redirect efforts towards recapping the psu board and ,,,

 

[The BXX's]

Many thanks for your suggestions!

Throughout the years, all the preowners seem to have taken a lot of care for the appearance of the amp, so I thought that it would be a some kind of obligation to make sure that internally, it comes close as much as possible to its original state. But indeed, regarding the meters, this will be quite a difficult task.

Please excuse the smartphone quality of the image.

 

[restorer-john]

Try to pick up a parted out CA-1010 or a scrapped one. The circuit could be easily copied and/or documented with some reverse engineering.

I'd be happy to draw out the schematic if I had a CA-1010.

 

[mbz]

Yeah, that's nice. I've got a 2010 and a 1010 in bits, partly restored. Forgot how nice they look, even with the meters.
Agree with the sentiment of others, you "only" need to replace an IC with some discrete components, not impossible.

 

[nj pheonix]

As far as sound IIRC, Yamaha had (11?) Fuses.
I'm guessing you found them all.
Then it has a number of fusible resistors.
I had one fail on mine. I think I'd check those first.
Also see your PS is in spec.
It would account for any and all of your problems.
I know there was a SM for this either in digital docs or hifi engine (perhaps both)

 

[The BXX's]

Let me say that this is really cool: People from the US, UK, from Australia, France, simply all around the world joining in to discuss this little problem ... You'll notice that I'm new to this here, but isn't this the beautiful side of the globalization?

Regarding the mentionend problem with the meter, there is some progress I am able to report on. I have found another CA-2010 here in Germany, not in the same good shape as the first one, even double its price, but at least original and complete. The module to control the meters is included but not working on the right channel (passing through the full supply voltage to the vu meter; luckily, the resulting full scale deflection was stopped cutting the wire before the vu meter itself was destroyed).

So my option will really be the brute-force-reverse-engineering-method, and it will be an extremely complicated thing. As you can see on the picture, the PCB and its components are completely drowned in potting resin, and I absolutely have no clue how the Japanese guy managed to dissolve his module so properly. Meanwhile, I was able to pull it out of its case, with the PCB freed on the soldering side, but all the components are still inside of this grey mass. I have started to try to dissolve it in DMSO (dimethylsulfoxide), which has some effect, but it's so slow that I don't expect it to ever remove it completely. In the meantime, I will already reproduce the PCB, but for the parts, their values and numbers—especially regarding the two transistors that are visible on the picture of the Japanese guy—this will be riddle wrapped up in an enigma.

I'm still open to any suggestions, but in any case, I'll keep you updated.

 

[OverLoad]

Having had my own personal CA-2010 with a borked VU meter many years ago, I decided to investigate the black box IC. The only thing I had to loose was a single working meter so I decided to carve open the box.
The parts are not encapsulated in potting compound, just the bottom of the PCB is. What I do is run some masking tape around the box as a guide and then dremel around it with a thin diamond wheel disc.

Out of all the CA-2010's I've since had in for restoration, I've had a total of 2 with meter problems. In both cases and including my own, the problem was with only one meter. The culprit in every case turned out to be the corresponding NJM4558 op-amp.

 

[The BXX's]

Thanks a lot for that valuable information. It means that obviously, I'm punished twice: Not only am I affected far above average by defective meter drivers in both my amplifiers, but it also turns out that Yamaha must have had the manufacturing process changed on my defective module, encapsulating it almost entirely in potting compound, c.f. annexed picture (excuse for the quality).

Your information also explains why the parts on the photo of the Japanese owner are so clean—his module wasn't drowned in that material, either. According to the google translator, he also reported that the problem he had with his meter resulted only from one defective op-amp.

As a first consequence, I can certainly stop trying to dissolve the potting compound with DMSO, because I will never manage to fully free the parts. Secondly, I will have to get manufactured a new PCB because repairing only the defective op-amp sitting in the middle of the potting compound will be impossible. But producing a new PCB shouldn't be the biggest problem.

On the other hand and that said, I would like to ask if you have the opportunity and possibility to provide some more detailed information on the specific parts that are used on your module(s). What I'm aware of is the op-amp. I measured the big tantalum cap, it seems to be a 47µ. Maybe it is also possible to measure the values of the resistors, of the remaining caps, and to find out which diodes are used.

But I will never manage find out the type of transistor that's on the PCB. So, is there any chance that you could take pictures of your module, or to name the values? There seem to be 2 x 14 resistors, 2 x 5 diodes, 2 x 3 tantalum capacitors, 2 x 2 transistors, and next to the big tantalum capacitor a part that I am unable to identify. If you know some more about that, it would certainly help to solve the riddle ...

 

[OverLoad]

Well isn't that a son of a gun, that's obviously the first box I've seen encapsulated. I'll knock on some wood and consider myself lucky having not encountered encapsulated ones as of yet.

I'm afraid your luck isn't about to get any better thus far. I had done this surgery with my CA-2010 a good 15 or more years ago and it has since found a new home.

 

[ants2au]

if you check out the Onkyo M504 schematic, it has a meter drive circuit that you can copy.
I think that would be easier to make than reversing what you have...

or if you want the simplest of the simplest design, look at the circuit of a technics su-z2. now that's cheap and cheerful

 

[clinic-audio]

Onkyo M504 meter drive circuit is not usable in CA2010 . Onkyo use FET TR 2SK246 GR obsolete today and YAMAHA circuit is using 2FET TR too but they look like 2QSK30A not difficult to find . These FET are outside the module .The bestway in my point of view is to make a new one , not trying to make any adaptation of one existing meter circuit

 

[clinic-audio]

2 x 2 transistors, and next to the big tantalum capacitor a part that I am unable to identify. If you know some more about that, it would certainly help to solve the riddle ..

These TR can be 2SC734 or 2SA561

 

[ants2au]

I dont think the FETs need to be there.
Only need from Q603 onwards...This is not a complex task.Q606 (6558) is the important part
you just have to cater for the different gain characteristics if the meters...

Onkyo M504 meter drive circuit is not usable in CA2010 . Onkyo use FET TR 2SK246 GR obsolete today and YAMAHA circuit is using 2FET TR too but they look like 2QSK30A not difficult to find . These FET are outside the module .The bestway in my point of view is to make a new one , not trying to make any adaptation of one existing meter circuit

 

[OMGCat!]

You can always go with something like this
http://www.ebay.com/itm/VU-Meter-Dr...463403?hash=item27fba29f6b:g:iZsAAOSwUuFW2A3B
rather than going through the trouble of remaking an entire circuit.
You may even be able to fit the black cover back over it to make it look fairly stock.

 

[nj pheonix]

You can always go with something like this
http://www.ebay.com/itm/VU-Meter-Dr...463403?hash=item27fba29f6b:g:iZsAAOSwUuFW2A3B
rather than going through the trouble of remaking an entire circuit.
You may even be able to fit the black cover back over it to make it look fairly stock.

If that worked , that'd be the way I'd go

 

[ants2au]

superb.. even better
seriously, you just need a buffer circuit...

 

[Mr. Yamaha]

I just opened my IC to see whether I can replace some parts preventively, and because I bought this CA-2000 as a project and before I started working on it, the meters didn't bounce up a notch at power up like they should. I opened it with a stanley knife. Inside there are:

• 2x blue tantalum 0,22 uF / 35V.
• 2x blue tantalum 47 uF / 6,3V.
• 2x green tantalum, had to see, but looks lik 1 uF /35V.
• 2x JRC 4558D (6073) opamp.
• 2x 2SC1432 transistor (Darlington).
• 6x unindentified (zener) diode.
• 4x small fuse / diode kind of thing (looks like fuses).
• Bunch of resistors.
• 2x unindentified grey capacitors (I guess).

I was planning on swapping at least the two opamps and the tantalums, but the problem is, I can't get to the solder side of the PCB. It's covered with 4mm of black sealant.

Any ideas on removin that stuff without damaging the PCB?