Sony Profeel KX-27PS1 Block Capacitor Alternative

[Retrorepair]

Hey guys,

I'm recapping this 35 year old set and I've got all the replacements together but I can't for the life of me find the 430uf 400v "block" capacitor.

Does anyone know of a commonly used replacement?

[ms660]

There's a 100uf and 330uf or a 470uf here if that's any use:

https://www.cricklewoodelectronics.c...-and-Tags.html

Lawrence.

[Welsh Anorak]

The 470uF, 400V would do the trick, but I'd question why it would need replacement. Most (though not all) Sony capacitors are of a high quality anyway, and I can't recall ever having to replace a main smooting block of this type.

[Retrorepair]

Thanks for that link, think I'll grab the 470uf.

I'm sure it is good quality but it's also 35 years old. In capacitor years that makes it about 130. I'm doing the rest (most of which have either leaked or have no esr reading) so why not

[Maarten]

There's no such thing as capacitor years. Capacitor lifetime is too dependent on various design and environmental factors to make such an extremely rough guess.

Mains smoothing capacitors normally run quite cold so have a very long lifetime (hours @temperature @ripple current). If still want to replace it even if the ESR is good (did you test it?), make sure to use a suitable type (the ripple current I just mentioned is a very important but often overlooked parameter) or it will last shorter than the original if you would have left that in place...

@Welsh Anorak: while this type of beaker electrolytics usually lasts for a long time, Sony was one of Elna's best customers, meaning lots of dried up and leaked electrolyte throughout the years. Mostly in miniature electrolyics. While I haven't replaced many electrolytics during the normal life span of Sony sets (except VHS power supplies and equipment using SMDs), a well used TV set will have some bad electrolytics after 20 or 30 years.

P.S. If the set has seen enough usage to have multiple electrolytics effectively go open, make sure to check the emission of the picture tube before investing too much time.

[Argus25]

Originally Posted by Retrorepair

Thanks for that link, think I'll grab the 470uf.

I'm sure it is good quality but it's also 35 years old. In capacitor years that makes it about 130. I'm doing the rest (most of which have either leaked or have no esr reading) so why not

Ha ! That is pretty funny.

Of course with Dogs & Cats you can divide their like expectancy into a Human lifetime say 80 years old and get say a 7 year old dog being equivalent of 40 years old.

Interesting with an electrolytic capacitor, because a lot of them are only rated for 3000 Hrs continuous use, which is only about 1/3 of a year. In that case the factor with respect to human years would be about 270, so a 35 year old capacitor on that basis would be 9450 years old.

We know they last longer than that, lets say 15 real years (like dog at best) because of intermittent use, making the ratio about 5.3.

So on that basis your 35 year old capacitor is 185 years old, so you got it pretty close at 130 years I think. You may well have a dog of a capacitor on your hands.

[Maarten]

The rated lifetime of an electrolytic in hours, is usually specified at max. ripple current and max. temperature. For every 10 degrees centigrade lower working temperature, you may double the rated lifetime. The function for ripple current is more complicated and often not given. It also influences the core temperature of the electrolytic, so there's some interaction between the parameters. Anyway, only looking at the working temperature, an 85°C electrolytic rated for 3000 hours, will last at least 48000 hours operating at 45°C. That's almost 5 years of continuous usage, or 15 years of reasonably normal daily usage. The actual ripple current being below the max. rated, might throw in a factor 4 or so as well, maybe more. A 105°C rated electrolytic will, ceteris paribus, last several lifetimes in the same application.

At the age of this particular set and regarding this electrolytic, the quality of the rubber seal is probably more important than the condition of the electrodes, separator and electrolyte - regardless of the hours of actual use it has seen. That's also a contributing factor as to why the smaller electrolytics are all dead while the larger electrolytics will probably last some more years of intermittent use.

That said, if the set is going to be run regularly I'd still be worried about the picture tube going low emission before this capacitor but if you're confident on the condition of the tube and have found a suitable replacement for the capacitor, replacing it certainly won't hurt.

In sets where damage can occur as a result of a failing smoothing capacitor (G11, I think) I would say it's more important to change it than in this case.

[Argus25]

Originally Posted by Maarten

That's almost 5 years of continuous usage, or 15 years of reasonably normal daily usage.

Yes 15 years as I noted, just like the Dog, we both agree !

[Maarten]

I was still updating my message after posting, I'm not sure if I had mentioned the ripple current at that point. However I did indeed notice the same 15 years that you mentioned. That's in my opinion the minimum time it should last with 8 hours of usage a day, not the average or maximum lifetime.

In a conservatively designed application, it might last 4 times as long but that's really too rough a guess. Some datasheet somewhere might have a few graphs on ripple current versus lifetime, but more often than not, such information wasn't given out.

Anyway, thinking some more about the tube life that I mentioned in my last post.. If the tube is good, the set most likely wouldn't have seen 48000 hours of use, so the quality of the rubber seals might be even be the largest factor in this case, regardless of hours of use.

[Argus25]

Originally Posted by Maarten

. If the tube is good, the set most likely wouldn't have seen 48000 hours of use, so the quality of the rubber seals might be even be the largest factor in this case, regardless of hours of use.

Yes, if the seals fail, electrolyte does not have to exit the capacitor for it to fail, only H20 vapor has to leave. This renders the capacitor basically useless exactly as happened to the capacitor in this link:

https://vintage-radio.net/forum/showthread.php?t=140044

Dunking it in deionized water returned it to its normal capacity & ESR.

[Retrorepair]

Well since I've no way to test the tubes emissions I don't know that it'll last but it's worth trying for my money. Any decent crt is hard to find now, for reasonable money at least so it's worth the risk for me.

[Maarten]

If at switch on, the picture is slightly purple or cyan, the emission is low. I've seen 22" Trinitron tubes of that era giving a crisp cyan picture without a trace of red and it was quite hard to explain to the customer that it was the tube, since it gave a "perfect" B/W picture.

On the other hand, I would never consider a Trinitron from that era as decent unless you need to operate the set at high brightness, but that's a matter of personal preference. The sets itself were quite nice! Just a shame Sony never got their indextron system to work on larger sizes or put their effort into designing a decent shadow mask tube.

[Retrorepair]

Would anyone know of a common issue with these where the H Amp and Pin Amp can't be adjusted? It's bowed in and there's big gaps either side. I've not replaced all the caps on the D board yet but I have a feeling it won't be those. Pin Amp ever so very slightly makes a difference but you really have to pay attention to see it.

I had a second 27ps1 which I've taken the boards from which seemed to have the same issue so just wondered if it was a known problem.

No tint when it's first turned on by the way so that's something I guess. As far as quality goes it may not be the best but it's from the same generation as my first ever TV so I've got a soft spot for it. That case design is beautiful too.

[Maarten]

I think the sets are nice too, so your soft spot is fully appreciated. It's just that I don't like the tubes but I do respect that Sony took the kludge and ran with it until the very end instead of using Trinitron only as a stop gap solution (until they developed something better or joined the shadow mask caravan) which they could have very well done.

I don't remember this chassis very well, but I think it uses a traditional diode modulator for the E/W correction. This is where the fault would be.

[Retrorepair]

Thanks, I'm struggling to understand what I'm looking for though, could you possibly point out where the diode modulator would be? The D board is on page 12 of the service manual here:

https://www.sendspace.com/file/60j1il

I can't see it properly on my phone so going to try and print it later today. I do recall seeing a diode that had got pretty toasty though.

[Red to black]

Your link didn't work for me.

Oh dear! this 27" version of the Profeel uses the rather expensive gate controlled switch (GCS) a SG264A as the PIN out active device, location Q512 on D board, this is a Sony special.

We dreaded repairing these back in the day as they could fail again hours, days or even weeks after repair and the price of replacement parts could soon reach very expensive levels, we dreaded the phone ringing after repairing one!

I think Sony did issue a repair/mod kit for these eventually but I no longer have the sheet.

[Red to black]

Looking a bit closer at my diagram:
The field rate parabola drive comes from the field stage around C504, R513 via the pin amp pot RV508 into pin 10 of IC 505 (TDA1082) which is the EW driver chip, as said GCS Q512 (SG264A) is the output device and D524, D525 in conjunction with C571 and C572 along with associated components such as L512 and L513 etc. form the Diode modulator proper.
If you are lucky and the GCS is ok it is likely that one of the associated peripheral components in the afore mentioned areas will be faulty.

These sets are typically Sony and multi-standard so there are a lot of things to check. I have only outlined the basic blocks here of the EW path.
Without the set in front of us it is practically impossible to fault find this from a distance, it will depend on your own understanding and fault finding skills here, unless someone here knows of a stock fault on these for this symptom.
C504 and R513 are worth checking, obviously the GCS needs to be healthy too, a scope and voltage checks as per the manual would help enormously too.

[Red to black]

Just a quick addition to the above, after looking at the block diagram the parabola output from the field stage originates from pin 6 of IC502 and coupled via C503 and R512 which is also connected to C504 and R513, some of these bits will be to shape the waveform, this also feeds the H convergence circuits.
So as you can see there is a lot of interdependence between various parts, a fault in one part could easily affect another.
The circuit alone is not very clear as to see fully what actually does what in places, this is typical of complicated Sony circuits and techniques, the block diagram does help somewhat with the sometimes convoluted diagrams, still not always easy to follow though.
I think you may end up needing some 'hands on help' with this.

As an aside we never saw that many of these. I think I probably saw more of its smaller sibling the KX 21PS1 which was a very different animal again.

[PaulM]

I have two of these monsters and a couple of spare tubes (probably good) which are FOC if collected from here (near Lincoln).

I have had the no EW fault and I can't for the life of me remember what the fault was for sure. However, I have a dim recollection that one of the sets came to me as an 'acquisition' and that the width had been turned up to maximum for some reason best known to the previous owner (aspect ratio 'fix'?). This meant that there was no headroom for the EW modulator to do its stuff and the sides were very bowed. Simply turning the width down returned things to the right shape and fixed the EW problem. Seems unlikely in this case, but is the width right?

Boy, are these things heavy - what a weight and a good advert as to why the Trinitron in large screen form was such a difficult proposition.

Best regards,

Paul M

[Retrorepair]

So looking at the diagram I should have 27v on the collector of Q512 but I've got 47v. Resistance of this pin to ground is about 151 ohm, not that exceptional.

I then started looking at voltages back down the line and noticed IC505 only had 3.3v supply voltage. Should be 12v.

Followed this back to R1529 and the 15v from the HVC header was present the other side. Out of circuit this resistor reads 3.1k and should be 68R! Did a quick swap from my parts board and presto, image fits the screen and all adjustments work again

Thanks for all the help guys, very much appreciated!

Paul - I'd take you up on your very kind offer but your 125 miles away, I'm in Essex. If I'm ever up your way though I'd be happy to take them.

As a side note, I've noticed when I switch the set on there's a red flash before the picture appears.. kind of hoping this doesn't mean the tube is on it's way out..