CA 610 repair

A buddy of mine asked for some help repairing this for his pops. They have had it since new and when it came to me the output was very low and almost none existent in the left channel. We took it apart and cleaned everything with board cleaner, compressed air and deoxit. Everything works well now and I also found a bad NPN in the power output section. It is circled in the picture. It was corroded very badly and smelt very burnt and fishy. We got a new NTE196 as a replacement.

I have pulled a few caps that were recommended in other threads mostly C579-C584.

Should we just bite the bullet and do all new caps?

I tested the output PNP and NPN transistors with a multimeter and they all seem to be about 5v and that seems within spec.

Anyone have caps replacement part numbers they have used with success?

Here are the output transistor measurements and they seem to be from what I can tell.

Last set of right output NPN/PNP pair.

I also found a bad NPN in the power output section.

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I'd replace them in complimentary pairs. Better choice would be
Onsemi's from Mouser,Digikey or Newark
MJ15022G and MJ15023G.

So it sounds like I sound just recap all the electrolytics and then get a couple sets of the these bipolar transistor pairs and have at it?

Junfan said:

So it sounds like I sound just recap all the electrolytics and then get a couple sets of the these bipolar transistor pairs and have at it?

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Go for it. No guts , no glory.

Sounds to me like I better put on an album, grab my camera, starting desoldering and labeling.

I just counted 46 total electrolytic caps on the board.

I wouldn't start desoldering until you have your new caps in hand. Like avionic stated, your outputs should be replaced by complimentary pairs, not just one at a time.

I understood that and thanks for the advice. Here is the spreadsheet of values and possible replacements depending on physical size and lead spacing.

I broke out the schematic and here are all electrolytics, their current values and some possible replacements I found. Thoughts? I will finalized each size as I remove them from the boards.

I have updated the spreadsheet and added a second page so you can sort however you like.

Someone mind taking a couple minutes to make sure the spreadsheet looks correct? My buddy would like to surprise his dad in a couple weeks with a fixed amp and it would be fun to see this sound like new again.

Junfan said:

Someone mind taking a couple minutes to make sure the spreadsheet looks correct? My buddy would like to surprise his dad in a couple weeks with a fixed amp and it would be fun to see this sound like new again.

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Have you compared your schematic list to whats physically installed ?

What about these ----- C409/410 220µf/6.3 vdc (bi-polar*)
C459 10µf/50vdc (bi-polar*)
C319,320,449,450 & 460 ---4.7µf/16vdc (bi-polar*)

these were pulled off the schematic. I don't have a CA-610 to physically verify.

* bi-polar or non-polar will do just fine. Nichicon "ES" if available. If not "EP" will do just fine.

Without knowing where in the circuit your replacements are going, it's hard to say whether they are the best cap for the job. some general rules of thumb though that I notice with your list:

I wouldn't bother with 6.3V caps as replacements. Go with 16V at least. Modern caps are much smaller and they should fit fine. ConradH has more info on failure rates of low voltage electrolytics, but 16V is the minimum value I buy any more, usually 25V.

Many will replace small value electrolytics with film capacitors. So, your 1uF caps could be replaced with these. The legs should be long enough at 5mm spacing to fit the holes:

http://www.newark.com/epcos/b32529c105k289/capacitor-polyester-film-1uf-63v/dp/21C0485

Often, <10uF caps might be in the signal path. Pioneer and Kenwood usually spec'd the orange low-leakage caps. So, your 4.7uF/50V caps might better be served by these:

http://www.newark.com/nichicon/ukl1h4r7kddanatd/aluminum-electrolytic-capacitor/dp/65R2234?ost=ukl

You might also consider audio grade caps on the Tone and/or Function boards (where the phono stage is located).

For power supply sections, and as a good general purpose cap with long life, many here will use any of the following:

Panasonic FM, FR, FC series
Nichicon PM, PW, HE, PS series
United Chemicon KZE or other low ESR, 105C rated cap.

I don't see many lists come across with the VR/VZ series unless there's none available in the above series. I also don't have experience with the Panasonic M series.

Good catch Dave on the bipolars. I haven't looked at the schematic.

You can go with " film " caps for all of those 1µf/50vdc caps.Like....And they have long leads .

http://www.newark.com/panasonic-ele...capacitor-polyester-film-1uf-50vdc/dp/49W2138

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Thank you gentlemen, I will update my parts list and add the spreadsheet back up hoping someone else may benefit in the future.

Have you compared your schematic list to whats physically installed? Yes I have and the numbers from the service manual and schematic do not match.

Not in service manual or physically found on any of the boards although they are listed on the schematic

C459 10µf/50vdc (bi-polar*)
449,450 & 460 ---4.7µf/16vdc (bi-polar*)


These were actually film caps in this unit.
What about these ----- C319,320,C409/410 220µf/6.3 vdc (bi-polar*)

I updated the spreadsheet based on this information and did find a single bipolar it was labeled as C519 and was listed as 1/50 so I ordered a replacement BP for it. I ended up using a Nichicon VP(M) series.

UVP1H010MDD1TD

Thank you guys for the help and hopefully others will benefit.

BTW. I removed C576 and it measured at 10.10uf so I know it was jacked and then I tested C579/C580 and one measure 570uf and the other 515uf so I believe one was outside spec.

So we redid the amp and fired it up last night starting at 25 watt in my DBT. We slowly walked it up to full voltage and the unit was very happy. We found a problem switch that needed another dose of deoxit and work. It was the input selection switch that was making the left speaker come and go.

We also installed silpads instead of reusing the mica pads along with the new transistors.

It sounded pretty nice and the input switch was fine on AUX so did our testing on that input. We cleaned the selectors and then set it aside to dry for a day or two. I believe now we simply need to set output levels, reassemble, solder all windings and set the output meters. It sounded very nice last night on my Bozaks.

We also took the time to test each cap with my meter and only about 10 out of the 47 or so tested within spec. It appears that maybe this was just dried out old caps all over the place.

NOTE: I identified a couple caps incorrectly and also found a couple I had missed. The spreadsheet is updated with the exact parts in this amp now including transistors.

solder all windings

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Really not necessary. Believe it or not. Wire wrap is a better connection than soldered.Provided it hasn't been molested since manufacturer assembly.

Well that saves a little time! Thanks

avionic said:

Really not necessary. Believe it or not. Wire wrap is a better connection than soldered.Provided it hasn't been molested since manufacturer assembly.

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We put this all back together last night since the final deoxit bath on input selector.

The bulbs are both burnt out and with a little research here and the search engine we figured out we need to check R575 I think it was and then get a couple new bulbs. I think they were 12v 80ma. I believe Avionic had that information in another thread but now I need to find the bulbs and thinking I should remove one leg of the resistor and verify it is working correct.

R575 is measuring 15ohm. It sounds like maybe I need to replace it. I have continuity across is and also from the legs to the pad and also the next hope in each trace. Should I just pop a new set of lights in and go or should I desolder this resistor and replace it?

Junfan said:

We put this all back together last night since the final deoxit bath on input selector.

The bulbs are both burnt out and with a little research here and the search engine we figured out we need to check R575 I think it was and then get a couple new bulbs. I think they were 12v 80ma. I believe Avionic had that information in another thread but now I need to find the bulbs and thinking I should remove one leg of the resistor and verify it is working correct.

R575 is measuring 15ohm. It sounds like maybe I need to replace it. I have continuity across is and also from the legs to the pad and also the next hope in each trace. Should I just pop a new set of lights in and go or should I desolder this resistor and replace it?

View attachment 584464

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R575 is suppose to be 15Ω at 2 watt
Contact Dave at dgwojo.com and he will fix you up with the correct lamps.Which are 14.5v at 80ma..

PS Are you using the Mk II schematic ?