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Forum 141

CTV 1974 PYE CT205; 697 Hybrid Chassis

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crustytv
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I did a swap today with @the_teleman, I had a PYE CT219 he wanted, and as he had three of these 205's I thought why not.

Forum 142

I'm really pleased to get this CT205, it's a lovely looking set, but more for nostalgia. You see, back in 2013 I transitioned from purely B&W TV repair to colour TV repair. I sold off my entire B&W collection, and the very first colour TV I obtained was the 26" PYE CT203/1.

It was a fantastic first time repair, with plenty of help from the good folk of this forum, it ignited the colour bug that still exists today. I fondly remember having a decoder fault and using the superb Les Briggs PYE decoder diagnostics managed to fix it. That TV gave an absolute cracking picture.

The set has not been touched since, not by the previous owner, nor whilst The_teleman has had it, so I shall have all the fun of finding out what's what with it.

As probably expected, the line timebase/PSU module has suffered on the uppermost right, top edge connector, in fact it is missing, and the wires have been soldered, to what remains of the edge. This is hardly ideal as it now restricts the removal of the entire module, unsoldering and resoldering those wires, is only going to end in tears. I've heard of these edge connectors burning up on the 697, but have never seen evidence of one until now.

Thankfully, @jayceebee once again comes to the rescue. John had already been designing a replacement board in Kicad and is not far off from sending the Gerber files off for production. They are fairly expensive as a special coating needs applying to the edge. Although, I'll need to find a replacement for the missing edge connector.

 

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Posted : 31/07/2023 2:04 pm
glenz75, PYE625, WayneD and 1 people reacted
Jayceebee
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No problem with the timebase, it's still a long way from ready and I was just playing really. Because of the edge connectors it needs an expensive ENIG (Electroless nickel immersion gold) finish to the pads. I did try to do a very simple 3000 PSU edge connector but the standard HASL (hot air solder leveling) was too uneven, and the PCB producer won't do bare copper.

Below is as far as I have got.

PYE TB

John.

 
Posted : 31/07/2023 2:31 pm
crustytv reacted
slidertogrid
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That's a lovely set Chris! I have been looking for one for some time the nearest I have got so far in a mechanical tuner metal time-base earlier model. Yours looks like a late CT205 having the black control knobs, Good to see it has the later grey focus unit that hopefully won't burn your house down! The earlier black plastic ones were a real hazard! A local TV shop had a big fire when they left a set running unattended over lunch break! 

I cut my teeth on the 205, the place I worked for when I left school had thousands on rental. That Timebase panel is fairly typical, in fact I have seen a lot worse. Watch the mains fuse on the top, the red cover is missing and they are a bit of a shock hazard like that. Most covers were missing after a few years thanks to field engineers, if you were lucky back in the day it was chucked inside the cabinet and could be refitted.

I will follow your progress with interest.  BTW I think the 26" CT203 you have came from a mate of mine did you buy it from Peterborough by any chance?

 
Posted : 31/07/2023 3:20 pm
crustytv
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Yes, the 203 came from Mick, I passed that on to @the_teleman (Chris F) a good few years ago, as he's an avid PYE collector as you probably know.

With regard to the CT205, I know Chris F has an EKCO badged version of this TV. Now, I've no idea if he intends on keeping it, but maybe if you cross his palm with enough beer tokens, he might sell. I do know he seriously has to downsize his collection as it's well out of control, and he knows this.

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Posted : 31/07/2023 3:25 pm
slidertogrid
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Mick has a lot to answer for ! I only had three TV sets in my collection until I saw his! All the sets I thought were long gone were there and it set me on a mission! Now my TV collection has taken over two rooms! 😀

  I really want the Pye CT205 version as that was the model I remember. I may consider a Invicta as I had a few of those and they are pretty much the same. I think the Ekco version had slider controls? I sold a white one that was a horrid thing and to add to that the customer was a right PITA! I would rather not have a reminder of it/Him!  If I can find a suitable set I would just let my earlier model go to make space. It is a case of 'one in one out' for me now! 

The set I really really want is a dual standard GEC colour that is the first model of set I bought, repaired and sold when I was still at school. I bought it for £25 quid back then how times have changed....

 
Posted : 31/07/2023 5:18 pm
Nuvistor
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@slidertogrid 

The 697 chassis, one I would prefer to forget, a chassis I think they tried to cut costs with while designing the 725 chassis, one that was on the whole fine.

Still repairs paid the bills.

Frank

 
Posted : 31/07/2023 9:28 pm
Nuvistor
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@crustytv 

Chris beware of those top edge connectors, from memory they are still live with 240v with the front switch in the off position. Caught a few engineers out. 

Frank

 
Posted : 31/07/2023 9:32 pm
Cathovisor
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Posted by: @nuvistor

@crustytv 

Chris beware of those top edge connectors, from memory they are still live with 240v with the front switch in the off position. Caught a few engineers out. 

Yes, they are. A monumentally stupid bit of design by Pye.

 

 
Posted : 31/07/2023 9:40 pm
WayneD
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Ah yes, this was the one with the magic disappearing focus control! Yours appears to have been glued back together. The plastic bracket seemed to get brittle and break way too easily.

 
Posted : 01/08/2023 8:54 am
malcscott
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@jayceebee I have nos loptx and triplers.

 
Posted : 02/08/2023 9:17 pm
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Jayceebee
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@malcscott Good to know but I think the one in Chris's set is good which he will transplant into the new PCB when it's ready.

John.

 
Posted : 02/08/2023 9:26 pm
crustytv
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Posted by: @jayceebee

I think the one in Chris's set is good

Actually, the set is a complete unknown, I've no idea if the LOPT, tripler, CRT or any other of the panels are OK. As I mentioned in the opening post, the LTB looks high hour and has suffered the plug burn up. I got this off The_Teleman, and even he hadn't powered it since getting it from a chap in Rugby a good few years ago.

I will test the tube, tripler and lopt in due course, luckily I now have the tripler tester and lopt tester.

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Posted : 02/08/2023 9:34 pm
crustytv
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Posted by: @crustytv

I will test the tube, tripler and lopt in due course

First up, the red label A56-120X, thankfully it's good, I'd expect it to likely improve more as I let run. Oh, and I found a date code for the TV, 5th Feb 1974, I was only 10 when this was new.

Next up will be the LOPT and tripler test

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Posted : 03/08/2023 1:26 pm
Lloyd reacted
crustytv
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In-circuit test of the 697 Line Output Transformer

The IT-5235 allows for in-circuit testing of the LOPT. This test being the easiest to make and faster than having to isolate components or removing the entire LOPT. The test includes the entire television horizontal output stage, including the LOPT and the horizontal/vertical windings of the scan coils.

To do this, you simply disconnect the anode cap from the PL509 or, if testing transistor line output stage, you disconnect the collector from the line output transistor. Then it's just a case of connecting the GND to the TV chassis and green (Ring) to the anode cap or lifted collector lead. Select ring on the tester and power on, and now select A through F tests to check the ring status. If you get unsatisfactory results, then an out of circuit test is probably advised before condemning the LOPT.

A "GOOD" indication by the meter will mean that the windings are okay and there are no shorts in any of the scan coils or LOPT windings.

As can be seen from the results of my test, the 697 passed all but two, E & F. This indicates there may be a fault somewhere in the line output stage, or an impedance mismatch, I'm not certain. The only way to really know is to power the TV and see what it tells me. However, for now, without desoldering it from the board, I'll accept the LOPT is likely OK but to be on my guard.

Hope that was of some interest.

lopt

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Posted : 03/08/2023 2:46 pm
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Nuvistor
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The only LOPTX I ever changed in the Pye hybrid sets was a dual standard one, this set is now 50 years old so it could be faulty but let’s hope it’s ok.

Frank

 
Posted : 03/08/2023 4:27 pm
slidertogrid
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@crustytv I think I have a second hand one if the worst happens. They weren't a common fault but they did fail, usually insulation failure - arcing or burning up as far as I can remember it was a long time ago... Triplers were another matter they did fail but they were a common failure on most chassis that used them.

I'm keeping my fingers crossed for you! 

 
Posted : 03/08/2023 7:51 pm
PYE625
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Nice set 👍 

Think the boost capacitor was likely to go short.

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

 
Posted : 03/08/2023 8:23 pm
Nuvistor
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@pye625 

Yes the mixed dielectric 0.47ufd were a stock fault.

Frank

 
Posted : 03/08/2023 10:02 pm
slidertogrid
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 Blue and White = Change on sight!  Same applies to the .1 on the first anode supply. It would go short and burn out the 100K

 
Posted : 04/08/2023 8:51 am
Cathovisor
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See also: the boost cap on a Decca Bradford, same device there.

 
Posted : 04/08/2023 12:16 pm
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