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-   -   Pilot PT650 "Spacemaker" Television (https://www.vintage-radio.net/forum/showthread.php?t=134302)

1100 man 25th Feb 2017 12:49 am

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This poor old thing has been stored for many years in very wet conditions and I suspect has not seen power for 40 odd years. Judging by the tide mark of filth on the inside of the implosion screen, it has been face down for some of that time which also explains the major score marks on the face.
The chassis is very heavily rusted in many places and the general condition is poor. Add to that the water damaged cabinet and the missing back cover and you have a set which no one of sound mind would want to restore.
Luckily, I have never claimed to be of sound mind, so I am going to give it a go. ;D Plus I rather like the design and the 21" tube, so it will be a set I will actually use to watch vintage programs on.
I am not usually a fan of wholesale component replacement before a tv is powered up but in this case, in view of the state of everything, I think it will be essential. Most of the black Hunts caps have the cases falling off and do not have a good reputation anyway. However, I will retain as much as possible and only replace what I consider necessary.
The chassis is built in a square, traditional style around the back of the tube and sits on two lower supports and the whole thing sits on the bench quite nicely.
There is a top panel which carries the power supply and frame timebase, right hand panel which has the line timebase and LOPT, left hand panel which carries the tuner, speaker and volume control and the lower panel which doesn't do anything exciting!
There is also a PCB, thankfully not double sided, which deals with the signal side of things.
So my plan is to strip the chassis into bite sized chunks which I can rebuild over the coming months.
The top panel has suffered the most rust and I will remove the Frame TB components and power supply, sand blast it and have it nickle plated. Same with the LHS and lower panel. The RH timebase panel just has too much on to be able to strip it down and is actually not too bad rust wise.
Sounds a bit extreme I know, but I do similar things with the car restoration stuff, so have access to those services.
So that's the plan anyway- sounds easy doesn't it :thumbsup:
Cheers Nick

Pictures of the 'before' state of things:

BassoonBloke 25th Feb 2017 10:40 am

Re: Pilot PT650 "Spacemaker" Television
 
Hi Nick,

Looks ok to me, just give it a wipe over, plug the crt socket back on and wind it up slowly on a variac !! (and stand back) ;D
I like a bit of a challenge myself and I don't see any reason that you can't make it work again as long as the main components are serviceable (and even then replacements can generally be found of some sort) CRT, Loptx and SOPtx.
I want to see it come back to life, so lots of pictures please.

Good Luck with it.
Alan. :thumbsup:

1100 man 25th Feb 2017 12:29 pm

Re: Pilot PT650 "Spacemaker" Television
 
Thanks for the encouragement, Alan. It will certainly be a challenge but absolutely nothing in comparison with what Andy Beer is doing to his HMV905. He is building it primarily from thin air as half the bits are missing and even winding his own scan coils 8-o Now that really is something to behold!
I am away on the Isle of Wight for a bit and wasn't expecting to get anything done on the Pilot until I get back to the workbench next week. However, I had an evening to myself on Thursday so using a chest of drawers, some basic tools and a gas powered soldering iron, set 'to'.
I've never 'de-constructed' a tv before, at least not with the object of rebuilding it again. I made various sketches of key areas and labelled interconnecting wires and took various photos. Mind you, when I rebuild it, I will primarily follow the circuit diagram but I don't doubt I'll make a few wiring errors. It makes you realise how labour intensive these were to build with everything hand wired. The advent of the PCB must have reduced wiring errors considerably.
The layout of components is a bit surprising in this set and I would have thought they could have improved on it.
All the line output parts are on the RHS chassis so you would expect the valve next to this to be the line osc/ sync separator, but no, its the sound output valve! As far away as you can get from the volume control, speaker and source of signals!
Conversely, the signals board, all quite sensibly on a PCB, contains the line oscillator, so the drive to the line o/p valve has to trail round the chassis on a piece if wire suspended on wire ties :dunce:
As Fernseh has already pointed out, some of the circuitry is a bit weird with reflex sound using the same valve to handle the IF and the audio :o
I am sure as I progress, more oddities will appear, but that all adds greatly to the interest.
By the end of the evening, progress was good with most of the key parts un-wired and the chassis panels ready to split.
Interestingly, the LOPT only has 4 connections to the outside world which are on spade connectors, so the whole assembly complete with rectifier takes seconds to remove. I wonder if they were expecting failures? It looks a sturdy, well made unit though and looks pretty good under the layer of grime. It has a good layer of wax which shows no signs of having melted so after being carefully dried out, will hopefully be ok.
On first glance, the Fireball tuner looks in a bad way. In fact, its mainly the case which has gone rusty and it's pretty good inside- just needs a very good clean and re-lubricate.
I now need to find a box to put all the bits in to move them back to Essex next week. Once back in the workshop, I can concentrate on the individual chassis panels.
Cheers Nick

1100 man 25th Feb 2017 12:38 pm

Re: Pilot PT650 "Spacemaker" Television
 
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Pictures for the above post are shown below. I've had problems with my computer crashing when I attach photo's, so it's safer after writing a long post to do the photo's separately :)

Heatercathodeshort 25th Feb 2017 9:28 pm

Re: Pilot PT650 "Spacemaker" Television
 
The P/C board and lopt will look fine after a clean up. You may get away with the Fireball too. Unclip the cover for an internal look. I'm following this one! John.

1100 man 25th Feb 2017 11:43 pm

Re: Pilot PT650 "Spacemaker" Television
 
Hi John,
The PCB does look in pretty good order although its not exactly flat! Should clean up well though. I'll replace the half dozen Hunts caps and the two tone electrolytic plus there are various resistors that look distressed. I did notice that one of the cores on an IF can has been wound very far out so maybe, as you suggested, it was twiddled to try and get better sound.
When I get that far, I will have a go at reforming the main smoothing can nice and gently which will hopefully recover.
The tuner is pretty good inside- just filthy! For some reason the wire spring that operates the 'clunk clunk' action is missing but I can come up with something.
I've just put it back in its case to make it easier to transport back to Essex tomorrow night and I must say it looks great- really cool design. The screen also looks huge! I shall enjoy watching it when it's done: only vintage programs though!!
I'm looking forward to Harpenden next weekend so I can stock up on caps from the BVWS stall as I now have three rebuilds on the go so that will keep me out of mischief in the evenings for quite a while :)
Cheers Nick

Sideband 26th Feb 2017 1:43 pm

Re: Pilot PT650 "Spacemaker" Television
 
I suspect some of the valveholders may have suffered due to water/damp so be prepared to change pins/valveholders as required.

Good luck with this one. It'll be fantastic if it all works again.

Heatercathodeshort 27th Feb 2017 10:03 am

Re: Pilot PT650 "Spacemaker" Television
 
The printed circuit tends to be a bit bent in this chassis. I suspect it will look a lot better when cleaned up. The chassis fortunately is a simple design but you may have to deal with the insulated 'lead through' pins that interconnect one side of the chassis components to the reverse. I'm not sure if you can still obtain these but I'm sure this very minor difficulty can be overcome.
I have bits of cannibalized Fireball tuners so should be able to sort out a spring if you cannot find something suitable. John.

crackle 27th Feb 2017 2:06 pm

Re: Pilot PT650 "Spacemaker" Television
 
Somebody asked me for the service information for this TV the other day. I scanned the ERT sheets and it is now on my website. So if you need the circuit to follow this restoration see http://kbmuseum.org.uk/other_service...52,650_ert.pdf


Mike

1100 man 28th Feb 2017 12:24 am

Re: Pilot PT650 "Spacemaker" Television
 
That's handy, Mike :thumbsup: Just what I needed as I don't have the 60/61 red book!
There are certainly some odd looking bits to the circuit- Fernseh must have been right when he said they used some dodgy circuit techniques! Why, for instance, does the main HT rail go to the frame scan coils? I've never seen that before!
The reflex sound has already been mentioned- again somewhat unusual in a TV. Also the contrast control in the video amp anode circuit and hence the 'tube drive' adjustment. Plus the grounded grid of the CRT and brightness & signal (with no DC restoration) applied to the cathode.
Certainly all a bit quirky, but that adds to the interest for me.
Having now returned to Essex, I now have some better facilities with which to work. I hooked the tube up to the B&K tester and it gives a perfectly adequate emission reading, albeit, with the anode volts wound up to max.
I have two CME1703's here which give exactly the same readings so either none of them will give good pictures, or they all will. I need to overhaul the Ekco T344 so I can use it to test out the tubes.

John, a scrap Fireball tuner would be very useful so I could make one good one. Especially the wire spring and the tin cover if you have those. I don't suppose you have a mains dropper or a speaker for one of these as well?

I've now removed what's left of the chassis from the tube and cleaned all the gunge from the back of the tube which now looks much better. The next thing will be to strip the remainder of the chassis and separate the four main panels.
That's all for the moment
Cheers Nick

FERNSEH 28th Feb 2017 1:42 am

Re: Pilot PT650 "Spacemaker" Television
 
Quote:

Originally Posted by 1100 man (Post 923088)
There are certainly some odd looking bits to the circuit- Fernseh must have been right when he said they used some dodgy circuit techniques! Why, for instance, does the main HT rail go to the frame scan coils? I've never seen that before!
Cheers Nick

A small amount of DC component will be introduced into the frame scanning coils which will cause a degree of picture shift. Also, because the resistors R92 & R93 are inserted before the main smoothing capacitor a tiny amount of 50Hz ripple will be present in the scanning coils. Why would the designer want to do that?
What is clear is that this circuit feature is present in all the Ultra and Pilot 1959/60 110 degree CRT models.
Some models such as the Ultra V17-70 have frame flyback suppression. A negative going pulse from the frame oscillator is supplied to the CRT grid.
Later models including the V17-80 "Bermuda" retain the wonderful CRT drive arrangement but instead of the high level contrast control system the contrast control is in the mean level vision AGC circuit.
It's worth mentioning that the high level contrast control was a circuit feature in many other TVs which were made by other manufacturers. Well known models that come to mind are the Pye dual standard models 3 and 11. Also many mid 1950s EMI sets including the 1824 and 1840 series of models.

DFWB.

1100 man 1st Mar 2017 1:25 am

Re: Pilot PT650 "Spacemaker" Television
 
1 Attachment(s)
Quote:

Originally Posted by FERNSEH (Post 923102)
A small amount of DC component will be introduced into the frame scanning coils which will cause a degree of picture shift. Also, because the resistors R92 & R93 are inserted before the main smoothing capacitor a tiny amount of 50Hz ripple will be present in the scanning coils. Why would the designer want to do that?
DFWB.

I was rather hoping you were going to tell me the answer ;D I can't see why you would want to introduce a DC component to the scan coils for picture shifting- after all there are magnets for that. Could it be some attempt to compensate for variations in picture size as the HT voltage varied? Or some sort of 'anti breathing' device to counteract the effects of mains hum in the frame timebase? That was the best I could come up with, although I'm not sure how either would actually work.
They must have thought it was a good idea as they used it in several chassis.

Anyway, the whole thing is now reduced to a 'PT650 self assembly kit' :-)
The next task will be to remove the remaining components from the frame timebase panel and the speaker panel so that these, along with the bottom panel can be sand blasted, prior to either re- plating or painting.
Cheers Nick

Heatercathodeshort 1st Mar 2017 9:18 am

Re: Pilot PT650 "Spacemaker" Television
 
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Hello Nick,
This is the contents of my 'Fireball' tuner box. You are most welcome to any bits you require. There is a screening cover and some retaining springs.
Note there are variations of tuners. Some have a large center hole on the coil disc and different valves are employed in some versions. The tuners themselves are probably U/S electrically.

If you get complete lack of signals on a Fireball tuner, check for HT volts on the anode of the mixer valve. [PCF80] If absent the fault will be due to failure of the tiny connecting wire from the IF output coil. It passes through a very short length of sleeving and chemical rot/green spot causes it to go O/C. It can be baffling when first encountered but easily repaired.

I can't believe that pile of scrap is capable of showing a picture again but I bet it does! Regards, John.

beery 1st Mar 2017 9:24 am

Re: Pilot PT650 "Spacemaker" Television
 
Hi Nick,
I have a spare fireball somewhere, I don't know what it is from or if it is any good, but it is clean and can at least donate a housing.
It will be a while before I can get to it though.

Cheers
Andy

1100 man 1st Mar 2017 10:27 am

Re: Pilot PT650 "Spacemaker" Television
 
Hi John and Andy,
Thank you for your offers of tuner parts. It looks like I have the large centre hole in the disk- the left hand one in your picture. The internals of mine look pretty good considering the state of the screening can- I will pay careful attention to the HT wire :o The wire spring on the right of your picture and the big outer metal screening can would be great though.
Are either of you going to Harpenden on Sunday? If so, maybe that would be easier than posting bits.
It does now look worryingly like a pile of scrap- but take heart, I am used to rust- I work on 1100's ;D
Its been fun so far, so I will keep at it!
Cheers Nick

flyingtech55 1st Mar 2017 6:14 pm

Re: Pilot PT650 "Spacemaker" Television
 
Quote:

Originally Posted by 1100 man (Post 922274)
Pictures of the 'before' state of things:

Ahharhhh! 'Tis but a mornings work Cap'n. Ahharrr!

TimR

1100 man 1st Mar 2017 10:49 pm

Re: Pilot PT650 "Spacemaker" Television
 
Quote:

Originally Posted by flyingtech55 (Post 923603)
Ahharhhh! 'Tis but a mornings work Cap'n. Ahharrr!

Yes, I was wondering what I was going to do in the afternoon ;D
Made me smile :laugh1:
Cheers Nick

1100 man 11th Mar 2017 11:29 pm

Re: Pilot PT650 "Spacemaker" Television
 
4 Attachment(s)
Good evening,
Well, I have been making progress with the project this week, although on the face of it it looks like I've been turning something that looked like a TV chassis into a pile of bits :o
I've never gone to this level before with a TV, usually I only do the minimum necessary to make it functional. Because of the dire state of this one though, it has rather lead me into a total restoration which is proving interesting and very enjoyable!
I have stripped all the components from the top deck which contains the frame timebase and power supply. This necessarily takes a while as I have been making sketches of the component positions and checking everything against the circuit. I have no qualms about replacing these components as most of them are very distressed anyway.
I was originally planning to keep the component side of the right hand line timebase board intact as this had not suffered too much with rust. However, I was going to replace the caps anyway and probably the high value resistors as well so I ended up stripping both sides of this board as well :D
Anyway, by this morning I had prepared all the bits of metal that I was planning to refurbish and had a large pile ready for sand blasting. (see third picture)
I have now finished the blasting and the last picture shows all the bits having been treated with anti-rust panel prep (basically phosphoric acid).
The plan was to get everything Zinc plated, but it seems we do not have enough other bits to make up an order. There is a £75 minimum order and I can't justify spending that on this project :shrug:
So the next best thing is to paint the bits. I share the workshop (car rather than tv) with two car bodywork guys which is handy as Jon has mixed some paint to match the original plated finish. This is metallic silver with a dash of light metallic gold. This gives a slightly yellow tinge which is how the original plated bits appear. The end result looks quite acceptable in the tests we have done.
Once I've neutralised the Phosphoric acid tomorrow, I'll have to mask off the connection pins in the chassis to prevent them getting painted. I tried removing them but they won't come out.
Hopefully, Jon is going to paint everything on Monday and then I can't wait to start the rebuild!
The first picture shows just how bad the frame timebase components were before being stripped.
Cheers nick

1100 man 12th Mar 2017 12:17 am

Re: Pilot PT650 "Spacemaker" Television
 
1 Attachment(s)
So to follow on from the above, other things have been happening as well.
I would like to thank John (Heatercathodeshort) for sending me a very respectable screening can for the Fireball tuner to replace the very rusty one that I had. He also sent a spring which was missing so once the front of the tuner is painted (carefully sand blasted today) I can clean and reassemble the rest of it.
I stocked up on capacitors from the BVWS stall at Harpenden at the weekend. Its a pity that even 630V caps are so small and rather yellow these days! I have been ordering in some of the other values I need for this project. I have also found a range of resistors I am happy with that look ok, so have ordered a good range of these.
I turned my attention to the poor old mains dropper which was looking very sorry for itself- its in two bits :'( Every section bar one that isn't used on 240V setting was open circuit! I imagine that constant water over the last 30 years may have had something to do with that!
Adding up all the heater voltages gives 137V which means 102 V has to be got rid of by the dropper- that's 30W 8-o Plus whatever the HT section needs to drop as well so the poor thing is going to get very hot and bothered. It doesn't help that it has a solid state rectifier for the HT- a PY32 would have added another 30 odd volts to the heater chain thus reducing the dissipation of the dropper.
It's a pity there wasn't a range of valves with lower current (say 100ma) and higher voltage heaters available to manufacturers at the time. (Or was there?) That would have eased the load on the dropper.
So if anyone has a spare dropper, I would be very grateful for it ;) John (HCS) said that even in the early 60's, they were difficult to find and suggested I make one out of RS 'polo mint' power resistors!! Granted they would be period- I regularly used to see them in sets I played with as a kid.
However, I'll put up a wanted post and see if anyone can come up with one or something similar.
I think that's about it for now; should be more to report later in the week.
Cheers Nick

Boater Sam 12th Mar 2017 6:28 am

Re: Pilot PT650 "Spacemaker" Television
 
How about 110v 25 watt bulb as a pilot lamp or even atop as a standard lamp?

Adventurous restoration Captain! Beat welding trumpets in 1100s.


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