Mouse Pye! CT222. 725 Chassis

[slidertogrid]

Hi Joe
I'm thinking of painting the bottom of the cabinet inside and out with a light brown acrylic paint just to reduce the staining, I may lacquer it then to seal it.

Today I took delivery of "Plan B". A If/tuner/ Sound panel in much better condition than mine. The If module isn't broken in half for a start! And a line panel also in excellent condition which alleviates my fears of doing all this work only to suffer LOPT failure.

A big thanks to Dave Dazzlevision for not only supplying these Pye - saving parts but also delivering them to the railway station! I am very grateful, Dave thanks!

In fact it may just be best to use this panel as mine may not play ball from the start. There was a lot of grot under the sockets and components at the bottom of the board. I hope to get a bit more done tomorrow, today has just flown by.

Thanks to everyone who has encouraged and helped out with parts for this project not so long ago I was on the verge of giving up!

Rich.

[slidertogrid]

I got back to the Pye today. I had cleaned the base of the cabinet and painted it with some acrylic paint I had spare. It has smartened up the base inside and out.

Today I dismantled the 'bus shelter' cleaned out the grot abraded the rust and gave it a coat of silver high temp paint again, a tin I had spare. The plugs that go to the bottom of the line board were grotty so I have cleaned then and I am giving them an overnight soak in cleaner. I'll put it back together tomorrow.

I then cleaned the scan-coils, tube base and wiring and got that lot ready to refit. Then after lunch when everything was dry the tube, wiring and scan-coils are back in!

Next will be to refit the front panel, fit the tuner drawer and the bus shelter. Then the panels can go back in and I can see if I can find where all the plugs go!

[slidertogrid]

It is now mainly back together, finding where all the plugs go was no problem as I had put labels on them, plus it was fairly obvious so long as you knew which panel the plug went to. Without the labels it would have been a bit daunting and slow.

The plugs at the bottom of the line board still need to go in I have left the sockets out of the panel as I am going to do continuity tests first to make sure they are connecting. There are a couple of others that were grotty I will do the same there.

Three wires to go on to the fuse holder and resistor on top of the dropper 'shelter' which will need fixing to the bottom of the cabinet somehow. the threaded fixings are rusted away and I didn't think it was a good idea to try and prise the block off the cabinet base to replace them.

Once the sockets are back on the line board it will be time to give it some power. I will load the power board with a 60 Watt bulb with the HT fuse removed in the first instance. I want to make sure the power supply is behaving before connecting the line output stage.

Fingers crossed!

[line sync]

I've been following this restoration and congratulate you for the work you've done so far.
Did you find a replacement speaker ?

Robin

[slidertogrid]

Hi Robin Thanks! To be honest I forgot about the speaker until I got the box of wiring out. It has continuity so I may have a go as Lloyd suggested at re-coning it if I can't find a replacement. I may have a cone donor!
Rich.

[line sync]

I only asked about the speaker because i might have one.
Is the impedance something like 25 ohms ?

Robin

[slidertogrid]

Hi Robin yes that is the one. If you have one and want to sell it please send me a PM.
Many thanks.
Rich.

[GLENZ32]

What a transformation from those first photos! You're certainly a brave soul in taking the time and effort in order to save this set. I'm guessing the Pye is getting close to a 'first power up'?

[slidertogrid]

First power up looks promising! I connected a bulb to the HT line with the HT fuse removed. so only the bulb was loading the output. After cleaning the set HT pots I metered the HT and switched on. The bulb lit and the HT was adjustable, so a good sign. I turned the HT down to 150V for now. Then with the input to the Tripler disconnected I fitted the HT fuse and switched on...

Tube heaters lit... Using a heavily insulated screwdriver I could draw a spark from the LOPT output. It is really annoying that I can no longer hear a 625 line whistle! I connected the Tripler and tried again. We have a raster! Out of focus, uncontrollable brightness, no signs of any modulation on the raster. My first suspect is a supply line missing? Maybe..

[slidertogrid]

I don't want to run it long until I have checked the EHT isn't excessive. Then I will see if the A1 controls will adjust and see what the voltages around the video output transistors compare to what they should be.
The video panel has had no attention other than a good clean and visual check for anything obviously wrong. If the state of the capacitors removed from the power line and frame panels are anything to go on it will need a few.
Philips capacitors don't like mouse wee or the fumes of it seems!

[line sync]

If you can give me a week i,ll have a look threw my speakers and let you know.
If I've got one you can have it and just pay me the postage.
Nice to see you've got something on the screen.
Along time ago i repaired a set with this chassis for a work colleague and was impressed by the easy access to the circuit boards.
Robin

[slidertogrid]

Many thanks Robin that is very kind of you.
Rich.

[19Seventy7]

What a fantastic result! Both in the cabinet and the electronic side of things. You’d never know the before and after were the same set! You’ve definitely done Lucien proud. Won’t be long before it’s happily playing away.

I look forward to seeing your progress!

‘77

[slidertogrid]

Thanks '77 . That is very kind of you. If you would like to see someone who really has done Lucien proud check out some of "look mum no computer" videos on youtube. Particularly the video about the Player Piano that came from Lucien. The fact Sam got it back together is incredible!

A bit more progress on the Pye tonight.
Further poking about has resulted in a picture! Well, ish !

I checked the collector volts of the RGB Transistors to find I had a few volts on each, then suddenly 130V on two and not a lot on the other...? Suddenly memory kicked in and so I gave the thick film a clout sorry, gentle tap... Then I had control over the brightness, so I turned it down and the contrast up - snow!!

Connecting the patten generator and tuning around has resulted in a very snowy low gain picture that comes and goes at will, the channel selector buttons are horribly intermittent which is to expected as they are one part that so far hasn't been out of the cabinet for a clean..

This 'ole thing really wants to go again!

[slidertogrid]

A bit more progress today I dismantled the button assembly and cleaned the board and contacts, A fiddley job! The set would then tune in and stay there. Now to the almost no gain... tap the tuner, nope, try a new aerial isolator, nope, adjust the AGC - it works but no improvement. Took the can off the IF module. Oh dear... Called Mick. I know he hasn't got any 725/731 parts but how about CT200? Any chance of a Ledco panel? He would have a look.

An hour later Mick arrived with a better service manual than mine, an EHT probe and... A Ledco IF module! Seconds later we have a snow free crosshatch that stays on tune! Greyscale is out, Lin is out, convergence is all over the place and the colour? Well no, that would be a lot to expect. It is getting there though.

The set is still running on low HT. I haven't been brave enough to turn it up yet! apart from static convergence and A1 controls no adjustments have been made, so it's not too bad considering . Next will be to set the HT and get the crosshatch somewhere near, once the black and white is right we can pursue the colour.

There is this funny intermittent squeaking though....

[agardiner]

This is such an amazing thread to be following. Probably the worst landfill rescue I have ever seen. Fantastic job so far.

Love the mice you have added.....

[bobbyball]

Very good progress then, keep it up!

I have several of the 110 degree tube versions, mainly in Dynatron guise. Need to get one of those going and see how it compares...

Don't let Mouse bring in any more of his friends

[Colourstar]

Those mice remind me of the ones on the 70s children's programme Bagpuss that used to sing 'We will fix it' when an old neglected item was brought into the shop for some attention. I hope they are helping you out too!

Keep up the fantastic work!

Steve

[slidertogrid]

Thanks for the comments, it is most encouraging! I would like to see one of the Dynatron 110 degree sets again. I remember one back in the day that suffered from every 731 chassis failing in the book! When the triper and LOPT failed it was the final straw and the set was stripped out and a new G11 supplied and fitted into the cabinet.

I have tided up the insides a bit, removed the labels I fitted and replaced the original label on the line cage and cabinet floor. Set the HT nearer but still a little on the low side, coward that I am! Convergence has set up better but a couple of controls don't work very well and one of the coils isn't adjusting at all so that will need sorting. As the mice ate the original control sheet I thought it was only fair that they should pitch in and help!

Then on to the decoder... Pots were intermittent and or open circuit, IC holders needed cleaning and the pins scraping, the crystal and a couple of Electrolytics had given up.. But eventually we have colour!
The decoder really needs aligning for that I will need a 'scope, tea and Mick, (Mick McMichael) He does the adjusting while I drink the tea!
Picture a little small due to the low HT Horiz shift pot doesn't work So still a bit to do.
Getting there...

[ekcopyephilips]

Re tapping the thick film module something my mum told me about then she worked at Pye. At one point she was in chassis algnment setting up the decoder and IF panel in a jig on this chassis. She said that sometimes you didn’t get any colour so the official fix was to give the delay line a tap and it came up every time.

Of course my mother knows nothing about electronics she saw me pulling our old one apart and pointed the delay line and told me “that blue thing there sometimes needed tapping, or we couldn’t set it up”.