Philips 17TG100U first light

[mark pirate]

I bought this 405 line set this morning, it is in remarkable condition, and looked complete bar the mains lead (typical), I whipped the back off to find the condition inside even more remarkable, lovely clean chassis, no obvious signs of previous repairs, and certainly not messed with, so I hard wired a mains lead in, insulated the power connector pins, snipped out the suppressor cap and slowly wound up the set on my variac.

At 150 volts, the sound came to life, followed by the familiar line whistle at around 180v, at 200v I was rewarded with a good raster, I plugged in the Aurora, and get a good picture, I was amazed how good the tube is (AW43-88), I don't think this set has seen a lot of use.

After a couple of minutes the picture darkens from the centre and then 'balloons'. I am hoping the LOPT is ok, and it is just down to leaky old caps.
I am hoping someone familiar with these sets can point me in the right direction with this fault.

Mark

[HamishBoxer]

Used to service those and remember when the PCL83 Sound o/put failed ,you lost the line stage.

[dazzlevision]

Originally Posted by mark pirate

After a couple of minutes the picture darkens from the centre and then 'balloons'. I am hoping the LOPT is ok, and it is just down to leaky old caps.
I am hoping someone familiar with these sets can point me in the right direction with this fault. Mark

Hello,

I have the same set and unfortunately, it quickly got through two LOPTs (I did change all the usual suspect Philips style black wax caps, etc.). Your set doesn't seem to have these, rather the dark green Polyester type, which are usually very reliable. I'm assuming they are the early version of the Philips/Mullard C296 series, which have the beige/"mushroom" colour cases.

I'd also check the line osc (ECL80), line output (PL36), boost diode (PY81/800) and EHT rec (EY86/7) valves first, before suspecting the LOPT.

In any event, I would check the boost HT reservoir capacitor (by replacement with a moderm Polypropylene type) and if it still plays up.....! At least these LOPTs aren't sealed with black pitch or wax. Note that, IIRC, two slightly different types of LOPT were fitted in this chassis (it is covered in the Philips service manual).

A stock fault on these is the 2.2M focus slider pot, which goes low, dragging the Boost HT line down. It's on the CRT base connector. I'd check that first and just snip it out of circuit for the time being.

Good luck,

Dazzlevision

[dazzlevision]

Originally Posted by HamishBoxer

Used to service those and remember when the PCL83 Sound o/put failed ,you lost the line stage.

Hello Dave,

I think the reverse is the case, isn't it? The PCL83 triode's anode is fed from Boost HT via a 2.7M resistor.

Regards,

Dazzlevision

[mark pirate]

Hi Dazzlevision, I think I have located the problem, when the picture ballooned, I could here the familiar sound of a stressed cap (see photo), this is getting hot & bothered (C608), I take it this is the boost cap?

I am working from the Philips manual.

Mark

[dazzlevision]

Originally Posted by mark pirate

Hi Dazzlevision, I think I have located the problem, when the picture ballooned, I could here the familiar sound of a stressed cap (see photo), this is getting hot & bothered (C608), I take it this is the boost cap?

I am working from the Philips manual. Mark

Hello Mark,

Well, I expect so, but I don't have the manual to hand at the moment.

If it's around 0.1uF at 750V working, then I think it highly likely. As it is clearly u/s, a
replacement will prove the point.

Regards,

Dazzlevision

[radiotircoed]

Looks like a good buy. Clean lines...

[dazzlevision]

Originally Posted by dazzlevision

If it's around 0.1uF at 750V working, then I think it highly likely. As it is clearly u/s, a replacement will prove the point.

Looking in the relevant R&TVS book, C608 is indeed the boost HT reservoir cap, with a value of 0.047uF.

[mark pirate]

Thanks Dazzlevision, I will trudge through the snow to the workshop and see if I have a replacement in stock, although I am pretty sure I have one, I think it is only rated at 650v, but should be ok for test purposes.

Looks like a good buy. Clean lines...

I do prefer single channel sets, but this set was in such good condition and a good price, It came from a house clearance, so was probably retired while still working, It has obviously been stored indoors, I am amazed at the fact it came up with such a good picture, I am more used to a cramped raster with terrible linearity due to all those leaky caps!


Mark

[mark pirate]

After replacing the boost cap, the set is now fine, so the LOPT is good, the linearity was expanded at the top, replacement of C413 made a vast improvement C210 was also replaced, these were the only pitch caps in the set to change.

It seems those green caps are fine, so I will leave them in situ.

I removed the chassis and tube to clean the mask and safety glass, this has come up like new, the cabinet was given a polish with T-cut, then polished with Pledge, it has come up a treat, the knobs and speaker grille were cleaned & the brass inserts were polished, then the set was reassembled.

The set now looks like new, the picture is excellent, there is a slight expansion of the top of the picture, and the focus control only makes a small difference, but the picture is well focused.

The set is very stable from switch on, the hold controls have plenty of range and sit happily near the midpoint.

This has been the easiest TV I have restored, the components are notable for their high quality, these must have been a very reliable set when new, I particularly like the swing out chassis, a real joy to work on.
The set has a date stamp of december 59.

I will give the set a good run today, and have some period programmes to watch this evening, I am now on the lookout for a set of legs to fit it.

Mark

[dazzlevision]

Hello Mark,

Nice job!

Did you check the focus slider's value? It is a stock fault.

I'm glad to hear the LOPT is holding out.

These sets are indeed very pleasing to look at, easy to carry (with those side recesses) and easy to work on with that swing-out chassis.

Regards,

Dazzlevision

[mark pirate]

Hi Dazzlevision, yes, I did check the focus slider, it has gone a bit low, measuring a little over 2 meg, I will change it though, I will have to see if I have a suitable replacement.

I will run the set over the weekend to see if any faults come to light, but so far it is behaving itself, not bad for a set that has not seen a picture for nearly 30 years!

I have a Pam 600F on the to do list, but i bet that will need more than 3 caps replaced....

Mark

[HamishBoxer]

Yes,DazzleVision age must have confused me!

[Welsh Anorak]

Hi
Great result - and so little dust on the chassis means it must have been retired early or else had a very low level of use. With few waxies it's the sort of set we dream of finding!
And look - it has a remote control (picture 4).
Glyn

[bobbyball]

What a great result!

I have one of these myself, currently in (dry) storage, and I'm itching to get to it now. It came from the house clearance auction for the grand sum of £1 ("plus buyer's premium") and as I remember has a nice cabinet too. I also have the larger screen version with the light sensor, but no Aurora yet. Must start saving up...

Great job there Mark, a worthy addition to your collection.

Robert

[mark pirate]

Hi Robert, this has been a real surprise for me, a TV is normally riddled with nasty waxies or crumbling plastic Hunts, this set only contained four of those nasty black pitch caps, dig out your set and get it on the bench, I expect you to have first light by tea time

You got a bargain for £1, mine was 15 times as much!

Glyn, it does indeed come with remote control (for the freeview box), I am pretty sure it has had an easy life, although it has had a few new valves in it's lifetime, but the tube must be close to 100%, the cabinet is also in excellent condition, just a few hairline cracks in the lacquer above the droppers.

Mark

[Tazman1966]

Hi Mark.

I had exactly the same fault with my Stella badged version (the ST1017U) and like yours it turned out to be the boost capacitor.

Although the circuits are identical, for some bizzare reason the circuit reference numbers are different

I would say that of all my 405 line sets, it's by far and away the best performer.

The story is in this thread here!

Well done sir, a lovely result.

[audiomagpie]

Nice results Mark. Brings back memories, as this was the set that we had for the first 10 years of my life. Many happy Saturday black and white tea times, Casey Jones, Bazil Brush, Dr Who, etc.

I also have the Stella version, but soon after achieving a good picture the LOPTX died.

Hope your's holds out!

Greg

[Hybrid tellies]

Great result looks really tidy. Glad the LOPT is good

[mark pirate]

I can report that after five hours viewing, the set has been stable, both holds stay rock solid, no loss of height or width.

If I have to be critical, the top linearity is slightly out (expanded), there is no 'top linearity' control on this set, just an overall linearity control, this was adjusted along with the height control, for the best overall results on test card C, there is a slight buzz on the sound at high volume, but this is down to the signal strength from the Aurora, I need to find my attenuator, as I have had this problem before....

It really bought back memories of my childhood, I spent all evening watching Steptoe & son, On the buses and Carry on cabbie, very nostalgic too see the glow round the mask!

I will give it some more use over the next few days, the picture quality is excellent, the tube really is top notch, the contrast & brightness controls are sitting around the halfway point, the LOPT seems fine, I ran the set for over an hour before refitting the back, the LOPT was only slightly warm, and the smoother cans cold.

This set is very useable, and gives the best picture out of all my restored 405 line set's, It has put up very little resistance to being put back into use after it's long sleep, remember the 405 line system was shut down in 1985.

Mark