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Stella ST2017U

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PYE625
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AKA Philips 17TG200U, this is the Stella flavour of set and is a fringe model equipped with fly-wheel sync.
I picked this up for twenty quid form near Royston via ebay. In the same family from new I believe, until now, and its in my grubby mitts.

It was rather dusty inside of course, but a good vacuum out revealed a nice clean chassis.
Basically nothing wrong electrically or otherwise apart from only four or five Philips black tar capacitors that required to be replaced. One was across the mains, and another on the boost HT rail. These were replaced before the set went near the mains :qq1
Main smoothing can reformed nicely, and mains applied.
A bit of knob twiddling and tuning resulted in good operation.
A cracking picture and a set I am pleased with. Excellent sensitivity and a damp string would be good enough to get a signal :bba

To understand the black art of electronics is to understand witchcraft. Andrew.

 
Posted : 02/07/2016 12:33 pm
Marc
 Marc
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Well done Andrew.
Looks like you've got yourself another cracking set to go in your collection. :aad

Marc.

Marc
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RSGB call sign 2E0VTN

 
Posted : 02/07/2016 12:57 pm
PYE625
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Cheers Marc,

rather boring really haha, no faults as of yet :qq1

To understand the black art of electronics is to understand witchcraft. Andrew.

 
Posted : 02/07/2016 1:00 pm
Nuvistor
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Only ever fixed a few of these but they gave excellent pictures and performed very well.

Frank

 
Posted : 02/07/2016 2:10 pm
PYE625
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One thing I like about this set is that the PLC83 triode section is supplied from the boost HT.
Basically, this means that there is no sound until the line stage is up and running, and no funny noises from the speaker as the set warms up.
But more importantly, if there is a failure in the line stage, a viewer will not keep the set running with sound only.
Looks like a protection feature possibly?

As a sync separator and phase discriminator (lovely big words :bba ) an ECH83 is used.
This a valve which was designed to operate with a low HT ( 50v maximum according to data ) such as in a car radio.
In this set, its anode voltage is 25v and 12v on the screen, but rather naughtily has 75v on the anode of the triode section.

I tried a ECH81 and it worked ok just the same, so I can't really see why Philips used the ECH83.
Perhaps someone with better knowledge than me will explain ? :qq1

To understand the black art of electronics is to understand witchcraft. Andrew.

 
Posted : 02/07/2016 8:18 pm
PYE625
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Today, I removed the chassis and tube for a clean.
Very straight-forward and the years of muck were removed from the plate glass front and inner tube surround plus various other cosmetic parts.
Re-fitting all the parts was also easy and it has turned out a real lovely clean set. The only slight thing is the cracking to the top of the cabinet of the thick lacquer, but I can live with that lol.

I forgot to mention that at some point, some bright spark had nicked the aerial socket.
I managed to fit a replacement using stand-off pillars and longish bolts.

To understand the black art of electronics is to understand witchcraft. Andrew.

 
Posted : 03/07/2016 1:40 pm
Katie Bush
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Hi Andrew,

It's a pity you live so far away.. A year or two ago, our own "Till Eulenspiegel" refinished the top of a console cabinet for me (French polished) and what difference it makes.. Till's method left a very smooth finish that merely required me to wait for a while (quite a long while) for the finish to harden enough for me to polish up to a deep shine.

Don't do this at home, folks....
I once heard of a neat trick that calls for methylated spirit, a match, and a LOT of nerve.. The result, I'm told, can be very good to excellent.

Marion

 
Posted : 03/07/2016 2:28 pm
PYE625
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Hi Andrew,

It's a pity you live so far away.. A year or two ago, our own "Till Eulenspiegel" refinished the top of a console cabinet for me (French polished) and what difference it makes.. Till's method left a very smooth finish that merely required me to wait for a while (quite a long while) for the finish to harden enough for me to polish up to a deep shine.

Don't do this at home, folks....
I once heard of a neat trick that calls for methylated spirit, a match, and a LOT of nerve.. The result, I'm told, can be very good to excellent.

Marion

Hi Marion, the meths trick sounds interesting.....what do you do with the match??? :aah

To understand the black art of electronics is to understand witchcraft. Andrew.

 
Posted : 03/07/2016 2:37 pm
Katie Bush
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Hi Andrew,

I only heard of it, never saw or tried it - so don't even try it :ccg I think it needs someone who's a bit expert at it, but as I understand it, the meths dissolves the existing finish, then flared off with a match, the heat melts the finish which runs and blends together again.

It's way too risky to try on anything that matters, and definitely not an indoor job - way too dangerous.

Have a word with Till, and see what he can suggest.. You never know, if he's down your way sometime, he might be able to give you a 'master class' on refinishing a cabinet.

Here's the thread in which Till did the cabinet top.....
http://www.forum.radios-tv.co.uk/viewto ... ent#p85904

Marion

 
Posted : 03/07/2016 2:55 pm
PYE625
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Erm....just noticed this.... :ccg

viewtopic.php?f=19&t=13315

Didn't know there was other interest, sorry Aidan.

You can see how dusty it was inside in the original ebay pics.

To understand the black art of electronics is to understand witchcraft. Andrew.

 
Posted : 03/07/2016 4:33 pm
Cathovisor
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As a sync separator and phase discriminator (lovely big words :bba ) an ECH83 is used.
This a valve which was designed to operate with a low HT ( 50v maximum according to data ) such as in a car radio.
In this set, its anode voltage is 25v and 12v on the screen, but rather naughtily has 75v on the anode of the triode section.

I tried a ECH81 and it worked ok just the same, so I can't really see why Philips used the ECH83.
Perhaps someone with better knowledge than me will explain ? :qq1

I think Michael W has pointed out in the past that to all intents and purposes, they are actually the same valve.

 
Posted : 03/07/2016 6:52 pm
PYE625
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I think Michael W has pointed out in the past that to all intents and purposes, they are actually the same valve.

I'm inclined to agree, as there seems to be no noticeable difference in operation or electrical conditions, with either valve in this set. I haven't bothered to put the ECH83 in a radio as I'm pretty sure it will merely confirm the above anyway.

To understand the black art of electronics is to understand witchcraft. Andrew.

 
Posted : 03/07/2016 9:21 pm
Cathovisor
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I'm inclined to agree, as there seems to be no noticeable difference in operation or electrical conditions, with either valve in this set. I haven't bothered to put the ECH83 in a radio as I'm pretty sure it will merely confirm the above anyway.

Here you go:

http://www.radiomuseum.org/forum/ech83_qru.html

 
Posted : 03/07/2016 10:50 pm
PYE625
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Well there we are then.

What about the ECH84? :bba

To understand the black art of electronics is to understand witchcraft. Andrew.

 
Posted : 03/07/2016 11:02 pm
Cathovisor
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What about the ECH84?

Strangely enough... that valve was developed for precisely the purpose that the ECH83 is being used for in your set.

http://frank.pocnet.net/sheets/030/e/ECH84.pdf

 
Posted : 03/07/2016 11:10 pm
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