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Old 12th Mar 2017, 11:23 am   #21
FERNSEH
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Default Re: Pilot PT650 "Spacemaker" Television

There is some old style TV mains droppers in the shop. I'll try and find one that will be suitable for the Pilot/Ultra TV. An alternative idea is a fixed voltage dropper. This was the solution used by the STC/KB service department for RGD and Regentone convertible and dual standard TVs such as models 624/5 and 194/5. For the Pilot PT650 I'd suggest for the heaters a total value of 345 ohms and for the HT supply 80 ohms. These values will be correct for 230 to 240 volt mains supplies. Calculating the wattage for the HT section gets complicated because although the total HT current might only be 120mA the charging current of the HT reservoir capacitor has to be considered. Play safe and use the highest possible wattage resistor available.

How about using the type of resistor shown in the attachment?

DFWB.
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Old 12th Mar 2017, 11:57 am   #22
Oliver35
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Default Re: Pilot PT650 "Spacemaker" Television

This is a great thread, it's fascinating watching things like this when they're being brought 'back from the dead' as it were. Looking forward to the next instalment!

Oliver
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Old 12th Mar 2017, 10:55 pm   #23
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Default Re: Pilot PT650 "Spacemaker" Television

Quote:
Originally Posted by Boater Sam View Post
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.
Nice idea, Sam! Maybe I could fit a couple of 15W orange pigmy lamps like they used to in '50's fan heaters to simulate the glow of a 'real' fire
Strangely enough, I am fitting a new inner wing and trumpet to my Morris 1300 at the moment- I just love rust

Thank you, Fernseh, for your resistor suggestion. However, I would like to get as close to the original arrangement as possible, so if you find a suitable mains dropper, I would be very grateful.
One particularly inspiring thing about this 'basket case' rebuild, is that it is forcing me to go to a level which I have never attained before. I have only repaired things to make them functional before by doing the minimum of work to them.
This project is different and is all about personal satisfaction. My aim (as with the 1100 restorations) is to end up with a TV which looks as standard as possible given the constraints of using some modern components where necessary. Where one draws the line is difficult, and everyone has a different idea. Some people go to immense efforts to re-create TCC wax capacitors and re- stuff electrolytics and I admire their efforts, but I feel that is a bridge too far for me. I do, however, want to use components which are at least similar to the originals- so blue resistors with 5 band colour codes and radial electrolytics would give me no pleasure. If the main smoothing can is past reforming, would I re-stuff it? Well, I can't guarantee that I wouldn't.. oh dear- its a slippery slope!!
Thank you, Oliver for your comments: I am glad you are finding the thread interesting and I will post updates when there is progress to report. I am following your cabinet restoration with interest and gathering ideas for the Pilot's sorry case!!
Cheers Nick
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Old 14th Mar 2017, 5:40 pm   #24
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Default Re: Pilot PT650 "Spacemaker" Television

Sales leaflet for the wood finish version with FM radio. J.
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Old 14th Mar 2017, 10:47 pm   #25
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Default Re: Pilot PT650 "Spacemaker" Television

Good evening,
Thanks for scanning the sales leaflet, John. Any idea what the model number was for the version incorporating the radio? Mine is the non radio version. 81 guineas must have been a fair whack back in 1960. Going through the process of de-constructing this set and rebuilding it, makes you realise just how much effort went into making a TV back then. The amount of individual metal components is remarkably large, all of which had to go through numerous operations- quite apart from then having to hand wire the various panels and then wiring those panels together. The labour per set must have been very high. Not to mention the rectification that must have been required to correct the inevitable wiring errors.

Anyway, there is some more progress to report. On Saturday, I sand blasted all the metal components and left them to pickle overnight in Phosphoric acid to kill any remaining rust. These were then neutralised on Sunday, washed and dried. The Phosphoric tends to leave a slightly powdery residue which on car bodywork we lightly rub down with 800 grade wet and dry.
The rubbing down was made particularly fiddly as several panels still had the connection pins in place (I couldn't remove them non- destructively ).
I then had to mask said pins on the top and bottom side of the panels with different size sleeving.
My good friend Jon (the bodywork guy I share a workshop with) then painted all the bits on Monday. He had already spent some time mixing paint to match the original plating colour.
The end result is actually better than I was hoping for. The colour, texture and sheen is pretty much the same as items we recently had nickle plated, and I think most people would be fooled
So I've cleaned up the valve holders and pop riveted them back into place and so the rebuilding of each panel can now start which I am looking forward to immensely.
Cheers Nick
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Old 15th Mar 2017, 1:42 am   #26
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Default Re: Pilot PT650 "Spacemaker" Television

I'm very impressed with the work that is being carried out to save what is a very rare set. I doubt if there is another similar set still in existence. We are all looking forward to seeing the end result.
The 21" Pilot "Spacemaker" with FM radio was designated as the model PT651.
The addition of FM radio was done in a very thorough manner. Although the tuner unit is common to TV and FM, when radio is selected the output from the tuner is the standard 10.7Mhz IF. The FM signals are processed by a separate two stage IF amplifier and a double-diode ratio detector. The resultant audio is passed to the reflex TV sound IF amplifier. The clever part of the circuit is the method of supplying power to the FM amplifier unit. On FM the line timebase is switched off and the HT line then supplies the 0.1amp series heater chain of the FM valves. The valves are two Mazda 10F18 pentodes and a Mazda 10D2 double diode.
Later TVs with FM employed a slightly different radio IF amplifier unit. The 10D2 was replaced by a 10LD12 triple-diode-triode. Check out my topic about the Ultra V1781. This set has FM radio.

DFWB.

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Old 15th Mar 2017, 10:49 am   #27
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Default Re: Pilot PT650 "Spacemaker" Television

Quote:
Originally Posted by FERNSEH View Post
I doubt if there is another similar set still in existence
Hi FERNSEH,
There is another PT650, I have one in my collection although the CRT is pretty poor.

Hi Nick,
I am following your thread with great interest, so far this restoration is amazing !
Keep up the good work.

Marc.
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Old 15th Mar 2017, 11:22 pm   #28
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Default Re: Pilot PT650 "Spacemaker" Television

Hi Marc and Fernseh,
Thank you both for your encouraging comments. So far, I am enjoying this project immensely: it has certainly given me plenty of things to think about. Doing the write- ups is also proving to be fun as well. The cabinet part of the restoration is going to be equally challenging as it has suffered as badly as the chassis. I also have no idea what I'm going to do about the missing back yet either.
I have not had a TV for 5 years now- I got fed up with modern ideas of program production and documentaries that seemed to be aimed at 3 year olds, so I pulled the plug out and have never plugged it back in since I certainly haven't missed it!
So the 'Spacemaker' will become my main TV to be used for watching vintage programs on so I have the added incentive of doing a nice job with it!
I received some more capacitors in the post this morning and I think I now have all the small components I need. I'm off back to the IOW tomorrow, so will be away from the workbench for 10 days. However, I'll take enough stuff with me and set up a makeshift bench so i can rebuild the timebase panels.
Marc, I came across the pictures of your set at 'Radiomuseum' when I was trying to identify my one. I think so far, they are the only pictures I have found. It would be really helpful if you could post some more pictures of the chassis from various angles and also of the scan coils as I think I may have a bit missing Have you got rid of the spiders yet?
Many thanks
Nick
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Old 16th Mar 2017, 12:30 am   #29
MonochromeMarc
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Default Re: Pilot PT650 "Spacemaker" Television

Hi Nick,

It may well take a few days but I'll try and get you some detailed photos of my PT650's chassis for you.

Marc.
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Old 22nd Mar 2017, 8:25 pm   #30
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Default Re: Pilot PT650 "Spacemaker" Television

Good evening,
Well I haven't been entirely idle during the past week I have now rebuilt the line timebase (and audio output) panel! Working from the circuit diagram and my drawings from when I dismantled it, it's been a case of methodically rewiring it and gradually adding components. It has been a surprisingly slow process to ensure no wiring errors and to follow the original layout, but I am pleased with the end result.
Having been sand blasted, the solder pins are very reluctant to take any solder despite careful cleaning and the use of separate flux. They are steel pins which doesn't help but they do eventually 'tin'.
I have re-used some of the small 'puff' caps- mostly the sort which don't give any trouble. I dare say I'll live to regret that I'm still a few components short and will order them tomorrow. I now plan to turn my attention to the frame timebase panel, after which all the bits and pieces which make up the chassis can be put back together. It will then start to look like I am getting somewhere!
Here's a couple of pictures of the nearly complete timebase panel- it doesn't look much work but has taken longer than I would have thought, but then, everything always does take longer than I think it will
Cheers Nick
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Old 22nd Mar 2017, 10:37 pm   #31
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Default Re: Pilot PT650 "Spacemaker" Television

That's looking good! Are those pins all chassis connections, or little insulated leadthroughs?

Oliver
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Old 23rd Mar 2017, 12:12 am   #32
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Default Re: Pilot PT650 "Spacemaker" Television

Hi Oliver,
All the pins are insulated leadthroughs. There are some components on the top and some underneath the panel. The pins that aren't connected on the underside have a mushroom head, I assume to reduce wiring errors during assembly.
They have made some very strange wiring decisions during the design process. For example, amongst the frame timebase components is C38 which is part of the sync separator anode circuit, the rest of which is on the IF pcb. So they have run a wire all the way round just to get to C38! Why not put it on the IF pcb?
The audio output and line oscillator are in the same valve envelope which is next to the line output valve. Consequently, half the audio circuitry is on the line TB panel and the rest is on the IF pcb round the other side of the chassis!
The earth points of the audio output circuitry are near the valve on the LTB panel except the cathode resistor which is returned to chassis via the screen of the co-ax which goes all the way back to the IF pcb!
All very strange and I'm sure involves more wiring than would be necessary with a better layout. Still, it makes it more interesting for me though
Cheers Nick
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Old 23rd Mar 2017, 5:48 pm   #33
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Default Re: Pilot PT650 "Spacemaker" Television

Hi Nick,

I still haven't been able to get to my PT650 yet to get you some photo's but looking back through some photo files I've found a couple of shots of the scan coils which I hope will help you.

Marc.
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Old 23rd Mar 2017, 8:34 pm   #34
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Default Re: Pilot PT650 "Spacemaker" Television

Quote:
Originally Posted by 1100 man View Post
For example, amongst the frame timebase components is C38 which is part of the sync separator anode circuit, the rest of which is on the IF pcb. So they have run a wire all the way round just to get to C38! Why not put it on the IF pcb?
Sounds like the sort of wiring I do when I'm extemporising on a project.. Being still something of a thermionic novice, I don't discover my howlers till much later.
I'm sure it's not significant (or maybe it is..) but I wonder what the capacity of all those to earth is.. And those high-mileage wiring runs, for that matter..

Oliver
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Old 24th Mar 2017, 5:54 pm   #35
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Default Re: Pilot PT650 "Spacemaker" Television

Hi Marc,
Many thanks for posting the pictures of the scan coils. They look far too clean: I haven't dug mine out of the filth yet but they do look to be the same, so I haven't got a bit missing.
Looking at your second picture, you can see the clamp which holds it on to the tube neck just a bit back from the tube base. What is the purpose of the aluminium ring just in front of the shift magnets? This can slide back and forward about 1/2 inch. What does it do? Also what stops it from moving, my one wabbles about in the breeze!
Just the other side of the clamp is a steel ring, directly in contact with the glass. Any idea what the purpose of that is?
Many thanks
Nick
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Old 7th Apr 2017, 11:09 pm   #36
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Default Re: Pilot PT650 "Spacemaker" Television

Hi all,
I am still working on this project as and when I get a chance or at least when work, sleep and beer don't get in the way
Tonight I have bolted the four main bits of the chassis back together prior to re- connecting all the inter panel wiring. The wiring will take a while as there is plenty of room for error.
There is a tag strip on the top chassis which carries the interlace filter components which I am just about to refurbish. There is a diode which according to the circuit is type Q1/5 about 1/2 inch long, 3/8 wide with a green and a black band. It measures open circuit.
Am I correct in thinking this would be a germanium type and I can use an OA91? Does anyone have any information about it?
I also experimented with re- forming the main smoothing cap. I tried the 100 mfd section first. Using a 280V supply, I limited the current with a resistor to about 5ma. Fairly quickly the current fell to about 1ma, so I decided to leave it on overnight. In the morning, the current had actually increased back to 5ma which I felt was not a good sign.
The end result after further messing about was when it was directly connected to the supply, it drew a steady 2ma. When it was disconnected, the voltage fell pretty quickly (my meter only draws 30 micro amps).
So I'm not sure I really trust it to do it's job either very well or very reliably.
I don't fancy it going short when I am using the set on a regular basis.
I have therefore, rather reluctantly I must say, decided to re-stuff it with modern caps.
I have never done such a thing before, but then I have not gone to this level with a restoration before!
My plan is to cut it under the clamp and then remove the innards. When I know exactly what the internal dimensions of the can are, I can select the replacement caps. Space will be very tight as there is a 400mfd, a 100mfd and a 16mfd in the same can! Also the 100 mfd needs to have a decent ripple current rating. Suitable replacements are actually quite large.
Anyway, that's it for tonight. I'll post some more pictures soon.
Cheers Nick
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Old 14th Apr 2017, 10:48 pm   #37
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Default Re: Pilot PT650 "Spacemaker" Television

Good evening,
Just a quick progress report and a couple of pictures. It's now starting to look a bit more like a TV chassis again with all the main bits bolted back together. I even managed to find some new speed fasteners the exact same size and style as the original rusty ones! The frame TX and mains choke cleaned up nicely and have been refitted.
I am now going to turn my attention to the IF pcb which needs some TLC. It needs a good scrub to get rid of the layer of mud on each side. There is a bunch of high value resistors which will need replacing and several crumbly Hunts caps. I will also remove the screening cans and check for obvious problems, check the coils for continuity and generally give it a good seeing to!
The cores all looked to have been well twiddled, but at least they all move. I expect a full alignment will be necessary.
I carefully cut open the main smoothing can under where the clamp will sit, and spent some time removing the innards and cleaning up the inside of the can. I have the new caps ready to install, but need to come up with a neat method of holding them in place.
Once the can and the IF board are ready, they can be re fitted onto the chassis and then most of the wiring can be re connected.
That will still leave the LOPT, all the pots, tuner, mains dropper, aerial input, rectifier, scan coils and speaker to attend to- so still a long way to go before first power up!
I noticed that 'MerlinMaxwell', on a thread about the Thorn 1500, was surprised how simple and how few components were needed for a B/W TV! Trust me, when you have to refurbish every single bit it seems that it takes a remarkably large amount of stuff to make a TV In fact, it makes you realise just how difficult it was, back in 1960, to make a TV at all. Not so much in components, but all the hardware: countless metal stampings, transformers, wire, plastic mouldings, nuts & bolts etc. Also to do this on a mass production basis and to keep costs as low as possible and to produce a reliable product was some achievement
Anyway, here are a couple of pictures of progress so far.
Cheers Nick
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Old 15th Apr 2017, 9:39 am   #38
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Default Re: Pilot PT650 "Spacemaker" Television

Given what you started with, this is astonishing progress, it looks brand new.. Are you painting or sleeving those caps, or are you finding black ones from somewhere? They look quite smart and inoffensive.

Oliver
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Old 15th Apr 2017, 10:14 am   #39
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Default Re: Pilot PT650 "Spacemaker" Television

Quote:
Originally Posted by 1100 man View Post
I have the new caps ready to install, but need to come up with a neat method of holding them in place.
Perhaps Marc's thread on the other forum may be of assistance:

https://www.radios-tv.co.uk/forum/in...itor-re-stuff/

Best of luck!

Steve
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Old 15th Apr 2017, 9:53 pm   #40
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Default Re: Pilot PT650 "Spacemaker" Television

Hi Oliver,
Thanks for your comments. I used heatshrink to disguise the caps as per the following: (nicked from one of my posts on another thread!)
I used black thin walled heat shrink to tone mine down a bit! Black the ends in first with a permanent marker, leave about 2mm overhang of heatshrink at each end and then use a hot air gun to gently shrink the tube. The overhang folds itself over the end of the cap quite neatly. The heat shrink needs to be thin walled, non adhesive type and be a fairly good fit before being shrunk.
I had to experiment a bit to get it right, but the end result at first glance looks remarkably similar to a Hunts cap!
I also tried painting a couple with satin black aerosol which worked ok but seemed more fiddly.
The original Hunts caps had their leads sleeved with yellow sleeving. After a bit of a search, I found a bit of 1sq mm triple and earth flat lighting cable in the old (proper) colours of red, yellow, blue. The yellow was just the right size and looked the part.
Thanks for the link, Steve. I have been trying to come up with an elegant solution for mounting the three new caps in my can. I was hoping to avoid kebab sticks and cable ties although that's a perfectly effective way of doing it!
I will hopefully get some time over the next few days to tackle the IF pcb and tuner.
Cheers Nick
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