Ceramic Cap for Electrolytic

[vol.2]

I'm going through my Sony KV-9200, and replacing all the out of spec caps. There is an electrolytic on the neck board, a 0.47uf 500V cap between the G2 pin on the tube socket and the flyback.

I can't find an electrolytic cap that fits those specs at any normal outlet, so I just purchased a ceramic cap. Is there any reason I shouldn't use the ceramic in this situation?

Thanks

[JohnCT]

A ceramic there is fine.

John

[vol.2]

Originally Posted by JohnCT

A ceramic there is fine.

John

Thanks!

I got an X8R class one, so it at least seems like it's a better cap than the OG. I guess maybe they just hadn't advanced ceramics quite so far in 1976 and they *had* to use an electrolytic. Or maybe there's some other reason I just don't know.

[JohnCT]

Originally Posted by vol.2

Thanks!

I got an X8R class one, so it at least seems like it's a better cap than the OG. I guess maybe they just hadn't advanced ceramics quite so far in 1976 and they *had* to use an electrolytic. Or maybe there's some other reason I just don't know.

Cost vs reliability was what they were looking at when selecting parts. A part that lasts 2 years is a problem, a part that lasts 80 years is a waste of money. They were looking for parts that would last 20 plus years and be cheap to buy.

Spending 0.25c for a better part doesn't seem like a big deal, but when you are buying a million of them and buying for dozens or hundred parts for a given model times the units sold, fractions of pennies add up big time.

That cap is a non critical bypass filter, literally anything would have worked.

John

[vol.2]

Originally Posted by JohnCT

Cost vs reliability was what they were looking at when selecting parts. A part that lasts 2 years is a problem, a part that lasts 80 years is a waste of money. They were looking for parts that would last 20 plus years and be cheap to buy.

Spending 0.25c for a better part doesn't seem like a big deal, but when you are buying a million of them and buying for dozens or hundred parts for a given model times the units sold, fractions of pennies add up big time.

That cap is a non critical bypass filter, literally anything would have worked.

John

That makes sense. Thanks for you insight. It's also reassuring to know that it's a non-critical spot.

[vol.2]

Originally Posted by JohnCT

That cap is a non critical bypass filter, literally anything would have worked.

John

I finished with the caps, and the last one changed was the big ballast cap that's in a can. It has a 470uf and a 10uf cap in it, but the schematic calls for a 470 and .022uf cap in the parts list, but a 10uf cap in the schematic.

I installed the .022uf cap instead of the 10uf that was in there. Do you think that one is an issue? I have some 10uf at 250 Electrolytics I can use. The parts list calls it a mylar cap. I honestly don't know what's in the can, but my guess is they are both electrolytic in there.

Thanks

[zeno]

I have never seen a can with different type caps so I would go
with the 470 & 10mfd. A caution on early Sony's. They would make
more than one chassis for the same model number. Sometimes TOTALLY
different chassii. Also supliments that almost always go MIA.
So having the model#, chassis # and serial # is important. When in
doubt stick with what it had especially SG613 sets !

73 Zeno
LFOD !

[JohnCT]

Originally Posted by vol.2

I finished with the caps, and the last one changed was the big ballast cap that's in a can. It has a 470uf and a 10uf cap in it, but the schematic calls for a 470 and .022uf cap in the parts list, but a 10uf cap in the schematic.

I installed the .022uf cap instead of the 10uf that was in there. Do you think that one is an issue? I have some 10uf at 250 Electrolytics I can use. The parts list calls it a mylar cap. I honestly don't know what's in the can, but my guess is they are both electrolytic in there.

Thanks

Odd that they would put a 470uf and a 10uf in a can and tie them together, unless Sony just had a metric sh*tload of these left over... The other possibility is when the caps are electrically tied together but are physically on the other side of the board, but that's pretty uncommon from my experience.

If a circuit needs just 10 more uf to run on top of 470uf, it's being run too close to tolerance which is something Sony wouldn't do, so unless they're just using a double can from left over stock, my guess is that it is a small value cap used to help snub out high freq noise.

Zeno makes a great point about putting two different types of caps in one can, but we *are* talking about Sony after all!!

Since 10 more uf won't make a difference added to 470uf in a bypass configuration, I'd be inclined to add a small value cap in place of the 10uf. If the 10uf is tapped on a point physically away from the 470uf section, I'd use a 10uf with a small value cap across it just to cover all bases.

John

[Electronic M]

Originally Posted by JohnCT

Odd that they would put a 470uf and a 10uf in a can and tie them together, unless Sony just had a metric sh*tload of these left over... The other possibility is when the caps are electrically tied together but are physically on the other side of the board, but that's pretty uncommon from my experience.

If a circuit needs just 10 more uf to run on top of 470uf, it's being run too close to tolerance which is something Sony wouldn't do, so unless they're just using a double can from left over stock, my guess is that it is a small value cap used to help snub out high freq noise.

Zeno makes a great point about putting two different types of caps in one can, but we *are* talking about Sony after all!!

Since 10 more uf won't make a difference added to 470uf in a bypass configuration, I'd be inclined to add a small value cap in place of the 10uf. If the 10uf is tapped on a point physically away from the 470uf section, I'd use a 10uf with a small value cap across it just to cover all bases.

John

The 2 caps are not wired in parallel. There's a 15K cap between them. A can type capacitor is always a single roll of foil.and dielectric, and it's always paper, or electrolytic, but never both at once.

[Phil]

At first I thought Tom might have gotten some bad weed as C904 A & B are shown wired in parallel and I don't know what a 15K cap would be. The schematic is obviously in error.
R602, a 15K resistor is probably between the two sections but according to the schematic R602 is shorted out by a connection between points shown as 21 and 7. So Tom is correct and the schematic is not! If we assume Sony didn't put a resistor in there and then short it out we have the 470 mfd filtering the incoming DC and the 10 mfd on the base of Q801, probably to reduce noise.

[JohnCT]

Originally Posted by Phil

At first I thought Tom might have gotten some bad weed as C904 A & B are shown wired in parallel and I don't know what a 15K cap would be. The schematic is obviously in error.
R602, a 15K resistor is probably between the two sections but according to the schematic R602 is shorted out by a connection between points shown as 21 and 7. So Tom is correct and the schematic is not! If we assume Sony didn't put a resistor in there and then short it out we have the 470 mfd filtering the incoming DC and the 10 mfd on the base of Q801, probably to reduce noise.

Actually, both the schematic and Tom are correct. What's not easy to see on a phone screen is that the caps aren't wired together at all - that line is the physical edge of the board's substrate that seems to be jumping the caps. If you follow that line, it goes all around the board and would seem to connect to a bunch of stuff.

Many schematics do that but they'd break up that line into dashes so there would be no confusion.

I'm so badly farsighted these days that blowing up the pic to see the caps meant I couldn't see the forest for the trees.

John

[Phil]

Quite correct. My mistake. Phone screens don't always show everything one needs to see!

[vol.2]

Originally Posted by zeno

I have never seen a can with different type caps so I would go
with the 470 & 10mfd. A caution on early Sony's. They would make
more than one chassis for the same model number. Sometimes TOTALLY
different chassii. Also supliments that almost always go MIA.
So having the model#, chassis # and serial # is important. When in
doubt stick with what it had especially SG613 sets !

73 Zeno
LFOD !

Ok! Yeah, I can do that. I don't want to because I already put the 470 and the 0.022 in there are pretty, but I guess if it came out of the factory with a 10uf, it's best practice to put that back in there.

For the record, this schematic and the parts list that said 904B was 0.022uf came out of the *same* service manual for the same chassis and model. My guess was that Sony just had the cans with 10uf lying around and were like "okay just use those it doesn't matter."

[Electronic M]

No weed...strongest stuff I touch is Tobacco and high proof alcohol.
I initially made the same mistake, but then I saw the board line loop around and short out the line cord and realized what I was looking at.