Yamaha CA-1010 -- doing a refurb, any preventative maintenance I should know about?

[cdfac]

Just got a beautiful CA-1010 to work over. I already DeOxited the switches and that took care of a dropped right channel, and I plan to do a full recap. Is there anything else I need to worry about?

According to the previous owner, Class A was very rarely, if ever, used over the last 30 years. Relays click fine. There is one 560R resistor in the power supply that looks like it gets a bit toasty, so I will replace it and its counterpart with a higher-wattage part. Looks like it will be a bitch to access the bottom of the "function" board without pretty much taking everything apart, though I have an idea about that.

One more question right now. Can I get a confirmation that the 22000uF/63V Nichicon Gold Tune filter caps fit? Looks like 50mm is the diameter and there is probably a bit more than 4" of vertical room, so they should work.

 

[avionic]

Can I get a confirmation that the 22000uF/63V Nichicon Gold Tune filter caps fit?

Confirmed. I very recently installed a pair in a 1010 here.. BTW Parts connex is presently out of stock. Was notified today by e-mail. Percys might have them .

 

[avionic]

There is one 560R resistor in the power supply that looks like it gets a bit toasty, so I will replace it and its counterpart with a higher-wattage part.

If its a fusible, A higher wattage is defeating its purpose.

Just checked .Its not a fusible.

 

[cdfac]

Another question. Should I just replace the tants on the "function board" with higher-end electrolytics like Silmics or something more workhorse/low-impedance like FC/FM? It's kinda hard for me to tell where the signal path is on that board, which makes it hard to judge the best replacement.

 

[avionic]

Another question. Should I just replace the tants on the "function board" with higher-end electrolytics like Silmics or something more workhorse/low-impedance like FC/FM? It's kinda hard for me to tell where the signal path is on that board, which makes it hard to judge the best replacement.

I don't think you could go wrong with Panasonics. I used what I had on hand.
Nichicon KZ and KA and it turned out pretty good.

 

[4seatPilot]

+1 on Nich KZ, or FG... size often an issue where the Tants are, so FG or KA will fit better than KZ sometimes.

tantulums are often in the sig path...

 

[cdfac]

thanks guys!

i had most of the caps on hand already for this job, but i do need to order some more. i've emailed PartsConnexion to see if they're still out of stock of the KG's. i have some crossover caps i need to order at the same time, and depending on the miniature electrolytics i choose, i might be able to get everything at once there.

 

[Vint Age]

Another question. Should I just replace the tants on the "function board" with higher-end electrolytics like Silmics or something more workhorse/low-impedance like FC/FM? It's kinda hard for me to tell where the signal path is on that board, which makes it hard to judge the best replacement.

If it were mine I'd use a 3.3 or 4.7uF film if it fits for C135/C136. :thmbsp:

 

[cdfac]

If it were mine I'd use a 3.3 or 4.7uF film if it fits for C135/C136. :thmbsp:

yes, i thought those looked like they might be some sort of coupling cap, but i was just going to use some KZ i already had. i DO have some 6.8uF Panasonic polypropylenes lying around, which are sizeable, but they could be shoehorned in there.

 

[Vint Age]

i DO have some 6.8uF Panasonic polypropylenes lying around, which are sizeable, but they could be shoehorned in there.

Even better. :yes:

 

[cdfac]

C139 and C140 are 3.3/50 in my amp, but marked 10/35 in the schematic. They are acting as decoupling caps, bridging the voltage rails in the phono amp back to ground. Is there any reason not to bump this up to the spec'd value, or even a bit higher? Seems like 3.3uF might have either been a mistake, or they just decided there wasn't a significant performance loss in dropping the value.

http://akdatabase.com/AKview/albums/userpics/10004/Yamaha CA-1010 Schematic.pdf

 

[cdfac]

one more thing i just noticed. i mentioned the 560R getting hot in the power supply. turns out that it had already blown and damaged Q410. i found an ECG196 box containing a smoked resistor (code unreadable) and a desoldered 2SD525. looking again, the ECG196 is sitting in the power supply next to a carbon comp 560R, both clearly sticking out as a repair job (though a good one). looks like the ECG crosses with the TIP41C, which I have seen on AK as a replacement for the 525.

this has me wondering -- is the problem just that that resistors were spec'd too low in power rating, or is there a deeper design flaw?

 

[avionic]

deeper design flaw?

If it were a design flaw. They would all experience the same type of stress.Not just your unit. Shoddy repair more likely.




Eye candy

2nd pix 22,000µf at 63vdc Nichicon "KG" from Parts Connex.

 

[cdfac]

If it were a design flaw. They would all experience the same type of stress.Not just your unit. Shoddy repair more likely.

sorry, i wasn't clear. my point is that the same exact issue happened to the AKer below in more catastrophic fashion, and i think i read about it elsewhere too. the repair in my amp's case was satisfactory (looks like it may have been back in '84, judging from a spec sheet filled out by a repair guy at the Audio Room in Cedar Rapids).

http://audiokarma.org/forums/showthread.php?t=499188

Avionic, if you've never noticed this part of the circuit as an issue in the CA-1010's you've worked on, then i won't worry about it.

 

[cdfac]

Confirmed. I very recently installed a pair in a 1010 here.. BTW Parts connex is presently out of stock. Was notified today by e-mail. Percys might have them .

lazy buggers. they never responded to my email asking if they were in stock, and since the site never changed, i figured they had them or would let me know right after ordering. well, i was half-right.

i put in the order, get the sales order form afterward, but never the shipping invoice. i finally email them today and they tell me that they (supposedly) emailed me right after the sales order form was sent out to tell me that those KG's are still out of stock and that i should choose a replacement. it's possible that it got lost in my junk mail, but that's a rare event since i do check it before deleting everything. i understand they don't have a "live" website as far as stock goes, but they mark stuff out of stock at least some of the time, so why can't they just make a note and update the site every time they have to send out an email like this?

now i'm stuck because i pulled out the original filter caps, and the amp is done otherwise. Parts-Connexion has no idea when they will be back in stock. i don't mind ordering from Michael Percy, but i can't decide whether to mail in my order or pay a bit more for quicker service... :scratch2:

 

[cdfac]

For anyone who has replaced these filter caps with screw-terminal caps and some sort of lug adaptor, can you describe exactly what you used? I'm trying to expand my options slightly beyond the KG's.

At the same time, I want to avoid snap-ins because I'd either have to go smaller than 50mm and shim (which I just don't want to do here out of stubbornness) or keep the 50mm and mess with the through-holes on the PCB (mostly because these boards seem more delicate than Yamaha's later ones).

 

[avionic]

Struck out at Percy's as well as Connex ?

 

[cdfac]

Struck out at Percy's as well as Connex ?

Haven't heard back from Percy yet, just exploring my options.

 

[cdfac]

Some pics, before I forget. Pretty standard, I guess. You'll notice the staggered Silmics in place of the tants on the function board (they seem to be in the phono section, actually). I also took the liberty of replacing some coupling-ish caps with larger film caps. I still have to put a dab of glue on them to keep them in place.

 

[cdfac]

So I went a slightly different route with the filter caps -- basically what I mentioned in the first post on this page. And you know what? It worked beautifully! What you see sticking out in the first two pics are these. You just clip the lug ring to expand it a bit (so it fits the cap screws), then align the lugs and bend them up over the screw to approximate the original off-center lug positions, and they slip right in the board! Because of the screw terminals, you need to give the caps a little extra clearance at the bottom, which you can kind of see in the third pic.

The filter caps are some nice EPCOS with very low impedance and ESR and very high ripple current capacity. The price was cheaper than the KG's would have been through Percy, plus the shipping was cheaper, plus I was able to add some interesting crossover caps as well!

Now the amp is done, the Class B bias is good, and I'm enjoying the results!