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irob2345
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I recently picked up a Kriesler 79-14 chassis and CRT from an unusual source.

A friend of a collector friend some years back sold this "lovely piece of furniture" (as most Krieslers are) 1964 vintage 23 inch TV on Ebay. When the buyer picked it up he indicated that he planned to re-purpose it as a drinks cabinet or some such abomination. So since the sale had been made it was agreed that the CRT and chassis would be pulled out and kept.

These large consoles and wideboys often go this way for lack of room.

But what do you do with a B&W chassis and CRT? My reason for saying yes was to strip it for parts, especially the impossible-to-find Philips NT3102 LOPT. And because the Philips AW59-91 CRT was strong. Not that I have a use for that CRT yet but you never know.

So consequently my US forum contact in Athens will now be able to get his Greek TV working after a nearly 2 year search! A bit like a heart transplant I suppose.

The 79-14 is a good example of Kriesler's high-end-product engineering. A well laid out, serviceable chassis that swings out for easy access.

Have a look at that nifty solution for a horizontal hold control. The clip restricts the user-accessible rotation to about 300 degrees but a tech can unclip it for more range adjustment if a part is changed.

Hard Life 6ES8
Donor chassis

 Interesting to note the evidence that this TV spent its life in a Deep Fringe reception area. That 6ES8 certainly looks like it's done some hard work!

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Topic starter Posted : 17/11/2020 12:23 pm
irob2345
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One other thing occurred to me about this TV - what was UK experience with the Philips Decal series of valves? We knew them as 6U9, 6X9, 6Y9 etc. I think the equivalent numbers are ECF200, ECF201, EFL200 etc. As expected the 1st and 2nd IF valves (it is a 2 IF stage design) have both been replaced.

We found they were a very short-service-life valve compared to earlier types. Pye locally avoided them completely and went straight to silicon transistors. Philips, Kriesler, Astor and HMV all used them and had similar experience. We used to modify our Philips rental sets in the late 60s to lower the HT4 voltage so they would last longer.

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Topic starter Posted : 17/11/2020 12:41 pm
Nuvistor
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@irob2345

I don’t recognise the ECF200, the EFL200 is probably a 6.3v version of the PFL200 that was used for video output and sync separator. Very high slope output pentode. Also used in some colour sets for CDA and luminance. The ECF201 is probably the 6v version of the PCF201, VHF tuner mixer/osc.

I didn’t have too much trouble with them but we were in a strong signal area..

By 1964 ease of access was becoming paramount in the mono TV’s for quick repairs. Some used a swing out or swing down chassis or a design with good access to both sides of the PCB.

Frank

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Posted : 17/11/2020 1:24 pm
irob2345
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6X9 = ECF200 which is the 6.3v heater version of the PCF200

6U9 = ECF201 which is the 6.3v heater version of the PCF201 (remote cut-off pentode section)

I've never seen one of these in a tuner. You might be thinking of the:

6HG8 = ECF86 which is the 6.3v heater version of the PCF86 and is B9A, not Decal.

6Y9 = EFL200 which is the 6.3v heater version of the PFL200 dual pentode

We only saw the 6.3v versions here in Oz. They were locally made by Philips. When that stopped and we got the imports, they were no better in terms of longevity.

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Topic starter Posted : 18/11/2020 11:29 am
Nuvistor
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@irob2345

I could well be wrong about the ECF201, long time ago. Still interesting  information.

There was still DC power to homes in the 50’s so sets had to be able to use AC or DC. That carried on well after DC had gone, the knowledge of how to safely make/use and repair Live chassis sets was well ingrained. An expensive power transformer would not sit well with the market especially the rental area were price out of the factory’s tended to be king.

Frank

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Posted : 18/11/2020 12:52 pm
irob2345
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DC power to homes in Australia was in South Australia regional areas mainly and just about all gone by the 1940s. The last DC generating / substation in Sydney had a single customer for many years, operating lifts. When the building was demolished that was the end of that. DC 1500 volts powers trains in Sydney of course....

We had a unique manufacturer - sales - service setup in Oz. The retailer was responsible for providing warranty service and so they built up service departments. Service techs would feed back to the retail divisions if they had to service a TV that they thought was dangerous and tell them not to sell such TVs.

If a kid pulled a knob off a TV and got electrocuted it was front page news in the papers - along with the brand of the TV - Ekco! There was thus a VERY strong incentive for manufacturers to make "safe" TVs that did not carry the deadly tag of "Live Chassis". Ekco very quickly designed a local chassis that had a transformer but it was too late, their brand was tarnished.

Because of economies of scale transformers became cheaper and set makers quickly learned how to make them cheaper still - the cost and indeed weight of a mains transformer wasn't that much of an issue. Polyester winding wire allowed plastic bobbin windings (no need for layering) further cutting costs. A transformer-based power supply could also be simpler and dissipate less heat. No big expensive dropping resistors.

Power supply authorities banned half-wave rectifiers because of electrolysis of the safety earths and the potential for DC saturation of pole transformer cores.

So there were many reasons Oz TVs have transformers.

When they put the K9 into production here in 1974, Philips used the isolated SMPS they designed for video input versions of the chassis, so we didn't get live chassis (or valves for that matter) in colour TVs either. Until much later, but that's another story!

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Topic starter Posted : 18/11/2020 11:05 pm
Till Eulenspiegel
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Apart from the PFL200 double-pentode and the PCF200 the decal base valves were never employed in UK made TVs in large numbers.

The PCH200 triode-heptode was used in certain Rediffusion TV sets as a noise cancelled sync separator.                                                                                                                                                           No matter how clever these valves were they came along at the time when manufactures were beginning to be more interested in transistors.

The PCH200 is an amazing piece of valve design. The electrode structures are tiny and yet they managed to assemble a heptode section with it's five grids. Also the 6.3volt version, ECH200.

Continental manufactures used the decal range of valves in much larger quantities.

The PCH200:  https://www.radiomuseum.org/tubes/tube_pch200.html

Till Eulenspiegel.

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Posted : 19/11/2020 10:43 am
irob2345
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Yes the Philips Decals, the GE Compactrons and the 12 volts only space-charge valves for car radios (remember them?) were all pushing against the tide of history.

It was really only the TV makers with some sort of connection with Philips that used them (except for Pye of course who successfully went solid state early). I think Kriesler was the only maker to go beyond one major chassis generation with Decal valves.

The HMV Y1-D3 and the V6 / V7 (almost identical chassis) used an ECH200. It was labelled a 6V9 here. The fringe version PW3 (3 stages VIF) dropped the 6V9 and replaced it with a 6BL8 and a transistor!

HMV chopped and changed a hell of a lot. By the PS and PT models the 6U9 was gone, replaced by a 6EH7, and the 6V9 circuit was back. Go figure! This was all on chassis that to all intents and purposes looked the same!

Philips themselves only used decal valves in the monopanel 11xxx series and never used the 6V9.

Astor made the very simplified, hand-wired Series 7 11" portable chassis (you can see this neat little wooden cabinet TV in the movie "The Dish") to try out the new valves. As it was a successful experiment they then put this design onto a PCB to make the Series 8 full size chassis. The following Series 9 was a hybrid and the decal valves were gone.

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Topic starter Posted : 19/11/2020 1:00 pm
irob2345
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Astor portable in Gainsborough cabinet

https://www.radiomuseum.org/r/astor_gainsborough.html

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Topic starter Posted : 22/11/2020 9:33 pm
Nuvistor liked
Nuvistor
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@irob2345
Downloaded the circuit from RM, look at that later, I like looking at different manufacturing designs.

Frank

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Posted : 23/11/2020 6:28 am
irob2345
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Yes me too!

This is a great example of "we don't know if this will sell so let's not invest too much in tooling"! Knobs are from the Astor parts bin for full-size TVs. And it shows.

It actually sold very well!

I have a CRT from a derelict one of those that I use as my test CRT, mounted in a plastic stackable storage bin.

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Topic starter Posted : 23/11/2020 7:40 am
irob2345
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On the subject of interesting designs, here is another interesting portable from Astor, released 1958 complete with two-tone paint and tail fins so redolent of the period!

https://www.radiomuseum.org/r/astor_sl_series_a.html

The power supply is unusual. It has 6.3v parallel heaters powered from a transformer but the B+ comes straight off the mains using selenium rectifiers.

I think this was the only live chassis Astor ever made, and their last portable until that wooden one!

Oh, another strange quirk of history which may or may not be apocryphal:

Astor and Holden (cars) had an ongoing relationship where Astor made "Genuine Accessory" car radios for Holden. This may have been a 2 way street because SL portables were painted in the same colours available on the 1958 FC Holden. It's possible Holden pressed and painted the cases for Astor. They were both based in Melbourne and the paint finish was of a uniformly high standard.

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Topic starter Posted : 23/11/2020 7:53 am
Nuvistor
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@irob2345
The Astor portable, just had 10 mins to look at it, and two points  come to mind which caused problems in the Pye 11U chassis, were the High Level contrast control failed and the preset contrast failed. The Pye preset contrast was 270k and the mod was to change it for 680k, both skeleton presets, the 270k burned up, slightly higher HT than the Astor. The High Level contrast track broke, possible burn out but could tell it was in a metal case, no mod for that just replace the control.

Did the Astor have similar trouble or were the pots better specification?

Frank

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Posted : 23/11/2020 9:44 am
irob2345
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Oh yes the Aussie made pots were better! It was rare to have to change one. The only UK-made pots we ever saw here were terrible!

Sorry!

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Topic starter Posted : 23/11/2020 9:45 pm