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1974 PYE CT203/1 - Hybrid 697 Chassis

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malcscott
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New degause thermistors in stock here! :thumb

 
Posted : 25/09/2013 6:16 pm
Anonymous
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The mains filter is on the power board.
the wires floating by the on/off switch is almost certainly where a coin meter was fitted.
your set looks in good condition its common to find blown tracks on the power board from the 4 pin connector in the centre top of the power/lop board.
please note there is mains on this panel even when turned off!.
most faults will live on the CDA panel .
on the lopt there is a 0.47mf cap(BIG) if its still the blue and white one I would change it its the boost cap and will fail.
good luck a very good set to start colour set restoration
Rob T

 
Posted : 25/09/2013 6:19 pm
crustytv
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Thanks Taz and Rob for the tips :aad I shall hunt out C301(.2uF), I'm hoping I can get at it without having to remove any boards but that might not be possible, we shall see.

Rob, interesting and thanks for clearing up the wire mystery, a coin meter! I would never have thought of that. I was going to remove it, at least I won't have this nagging , what the heck was it for turning over in my head. Thanks also for the warning about that board being live even when switch off, I always unplug sets rather than relying on the switch but it always helps to have all this info fresh in the mind and for others too.

Hi Malc,

I should have known MSS ( Malc's Speedy Spares) would have some in stock, I bet they were in those big bin bags you hauled 20+ years ago :bba I might pop over tomorrow morning sometime.

Chris

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Posted : 25/09/2013 6:47 pm
malcscott
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Hi Chris, you are spot on! I got these thermistors from Rediffusion 30 years ago. I should be in anytime tomorrow, Malc. I have sorted out degause thermistor and resistor for you.

 
Posted : 25/09/2013 6:54 pm
Doz
 Doz
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Possibly the last set I repaired before I closed the door on my business in 2000 was one of those.

It made an appearance every 3 or so years for minor titivation. It had a cracking tube, and pin-sharp picture last time I saw it, although it had a taste for red PCL802s, even after I modded it. Belonged to an old girl who was well into her 80'd, and didn't want anything newer. She said not having a remote control kept her from seizing up in her armchair! There's a box somewhere in here marked "Mrs P's spare tripler" , which is hers!

 
Posted : 25/09/2013 8:43 pm
crustytv
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Good news regarding the CRT which is a Blue label Mullard A66-120X :-

Posted : 25/09/2013 9:39 pm
Katie Bush
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I always though these were pretty good sets.

I seem to recall the main issues were, self immolation of the mains power plug(s) on the PSU/timebase chassis, crumbling focus units and roasted CDA panel.

Keeping the sets cool always seemed to be a key feature, and keeping them dust free was helpful in acheiving this.

We had one or two of these of our own, and I even had for my own use for a fair while.. Mine had the "normal" valve bases on the CDA panel, and the panel had to be changed, eventually, but my granddad just happened to have a spare one with the stand-off valve bases.. It was never any bother after that. :aad

Marion

 
Posted : 25/09/2013 11:06 pm
sideband
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I have a feeling that valveholders with a higher stand-off were used in later sets unless I'm thinking of another model..... :aaq

You've pretty well summed it up Marion. I seem to remember that there was also a change in value of the grid leak resistors on the PCL84's from 820K down to 680K which tended to stop the valves going into grid current.

Rich

 
Posted : 26/09/2013 9:26 am
Refugee
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Sideband.
You are likely to be right about a later model. I am sure I have seen one that looked similar with PFL200s in 10 pin sockets. Not very many valves were made with 10 pin sockets but they did exist.

 
Posted : 26/09/2013 12:10 pm
crustytv
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Visited Malc's Speedy Spares this morning, picked up a NOS Mullard VA8650 and a couple of 1KV caps for the Line stage. Malc also allowed me to call upon his experience and recall of the 697 chassis, he gave me some hints and tips which will no doubt come in handy.

Armed with this knowledge I've set about as per standard practice on the PSU section which also happens to have the Line output stage as well. This required the 5 edged connectors to be prised off the sides of the large PCB and two screws at the bottom securing the unit, this allows the whole unit to slide out for better access.

One of the edge connectors upon close inspection had suffered damage, I would imagine someone used a little too much lateral force and the end edge of the plastic connector has broken off. This leaves the last spade loose, it was pushed on the the PCB and was quite secure. I will use some milliput epoxy resin to repair the end and fashion it to look the same. See photo below photo 4

The main smoothing can ( red) looks to have a minor bulge and some electrolyte has oozed. I don't recall any issue with this cap when the set was last powered on but we shall see. As per advice I will replace the large Boost cap which sits on the LOPT and the A1 cap.

I forgot to also mention the Valves in this Hybrid

Valves

  • V1 PL509 Line Output[/*:m:21kgwfpm]
  • V2 PCF802 Line Oscillator[/*:m:21kgwfpm]
  • V3 PY500A Efficiency Diode[/*:m:21kgwfpm]
  • V4 PCL84 R-Y Amp and Clamp[/*:m:21kgwfpm]
  • V5 PCL84 G-Y Amp and Clamp[/*:m:21kgwfpm]
  • V6 PCL84 B-Y Amp and Clamp[/*:m:21kgwfpm]
  • V7 PL802 Luminance Output[/*:m:21kgwfpm]
  • CRT Mullard 26" A66-120X, 25kV[/*:m:21kgwfpm][/list:u:21kgwfpm]
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Posted : 26/09/2013 12:18 pm
AidanLunn
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Some may like it, others may hate it, when starting a new restoration it's been customary for me to dust down the TickTock Time Machine, (TTM) set the controls for the intended destination and see what was going on at the point in time. I forgot to do that, so here we go, ready for the ride? Those who lived it might find the mental images too traumatic............................. :aal

Arriving in 1974 I find my attire is somewhat embarrassing but at least I will fit in. Starting with the 6 inch heels on my brown, orange and green platforms. Followed by a rather fetching pair of green Oxford Bags, an even more interesting maroon shirt with round collars dumbo would be proud of and finally.... Oh the shame, a knitted tank top. A glance in the mirror and I see the TTM has provided me with a rather large set of sideburns too.

The house! well 2" turquoise shag pile looks like it needs a comb. I seem to have a black PVC settee with orange cushion covers and curtains with massive orange and brown flowers. Meanwhile over in the corner is the obligatory 70's home bar, complete with Cinzano, babycham, a Party Seven, Pineapple Ice bucket and Tupper-ware bowls with cheesy footballs. The one sight that greets and gets me all excited is the brand new rented 19" Decca....... drooool. :aag

I can't resist so switching it on I get to see what's happening in 1974.

Abba have just won the Eurovision in Brighton and their winning song Waterloo has just hit number 1.

News events :-

  • The Terracotta Army Unearthed[/*:m:1cvipgw8]
  • Nixon Forced to Resign[/*:m:1cvipgw8]
  • Lord Lucan Disappears[/*:m:1cvipgw8]
  • IRA Bombing campaign of Britain underway[/*:m:1cvipgw8]
  • Resignation of Mr Heath's Administration[/*:m:1cvipgw8][/list:u:1cvipgw8]
  • At the movies

    • The Great Gatsby[/*:m:1cvipgw8]
    • Towering Inferno[/*:m:1cvipgw8]
    • EarthQuake [/*:m:1cvipgw8]
    • Blazing Saddles.[/*:m:1cvipgw8][/list:u:1cvipgw8]

TV events:
The launch of Ceefax
First episode of Rising Damp
Last episode of Steptoe and Son
Jon Pertwee hands the keys of the TARDIS over to Tom Baker

 
Posted : 26/09/2013 2:02 pm
crustytv
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Cleaned up the valve pins on the PY500A & PL519.
Cleaned the PCB edge contacts with a fibre pen until they sparkled
Replaced the C222 .47uF 1000VDC Boost cap.

Still hunting the filter cap, not where I expected it to be.

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Posted : 26/09/2013 2:06 pm
malcscott
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There is a large cap to the right of the rod thermistor, could that be it ?? I think it was mounted upon the back of the on/off switch? i could be wrong. My brain was in a permanent drunken haze in the 70,s, Malc.

 
Posted : 26/09/2013 2:17 pm
crustytv
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Are you referring to the thermistor on the PSU assembly? that's near where the mains flex enters the set if so that's C302, I'm looking for C301 ( .2uF). I've had a look around the on/off and there's nothing. Of course it could have been removed already but I want to be sure.

It's probably around somewhere, my eyes are not what they used to be and access is difficult. I will get the mag lamp out later and see if I can get a better view.

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Posted : 26/09/2013 2:37 pm
Anonymous
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Chris
I was wrong the filter cap C301 was across the mains switch
rob t

 
Posted : 26/09/2013 4:44 pm
crustytv
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I know I can be a bit dim sometimes but honestly guys I don't think it's there.

I have checked the service manual and it clearly shows C301 located on the On/Off ( see pic) I have taken a photo of the self same physical and you can see nothing. I checked over on the PSU board and found nothing over there. Now I'm not sure if there were subsequent CT203/1 mods and they located it elsewhere and I don't have the updated data, I suppose it's a possibility but gut says no.

Could it be related to the coin device?

If you remember I had a white mains flex that had been connected across the on/off. It was just left attached with the other live end just floating but taped up, ( I've since removed that) I wonder if when the coin device was fitted they lifted C301, relocated it to the device or perhaps that had one already. When the coin device was removed the set was left without a mains filter, which is not a problem in itself.

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Posted : 26/09/2013 5:19 pm
malcscott
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It looks like it has long gone. Forget about it! Malc.

 
Posted : 26/09/2013 5:27 pm
Focus Diode
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I seem to remember that there was also a change in value of the grid leak resistors on the PCL84's from 820K down to 680K which tended to stop the valves going into grid current.

Not sure if this was an official modification, but it certainly seems to help. I think the three PCL84 grid leak resistors are 2M2. Certainly replacing with 680K ones helps calm things down. The PL802 grid leak resistor should also be changed to 2M2, I think it's 4M7 originally.

I once had a strange fault in which the red gradually faded out as the set fully warmed up. Replacing the grid leak resistors cured the problem without having to replace the relevant PCL84.

Brian

 
Posted : 26/09/2013 6:26 pm
crustytv
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As I mentioned before one of the edge connector plugs had been broken which resulted in one of the spades being loose. This loose spade had been pushed onto the PCB, although this made a good connection it would be better to be part of the plug again.

I decided on Araldite and sawdust, this seemed to be near match to the faded plug colour. I used a cable tie to hold the spade in place, this was positioned to the rear of the plug so as to not foul against anything. I then rebuilt the end as best I could using a cocktail stick to shape the resin. It's not perfect but should be a whole lot better than a free floating spade.

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Posted : 26/09/2013 8:31 pm
Anonymous
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I bet that's plug B the one with the 4 mains connectors its common to find burn ups on this plug caused by the contacts being not tight enough.
Rob T

 
Posted : 26/09/2013 9:02 pm
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