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.
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.
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!
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 wasn't about 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!
So far so good....I connected a bulb to the HT line with the fuse HT fuse removed. 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. 😎 With 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?
Enough for today, the bungling will resume tomorrow!
Wooo Hooo! It lives!
Nice work Rich, this TV will have to be named Phoenix from now on.
Look forward to the next instalment.
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Wow, that’s a surprising result!! Funny it’s always the nice condition sets that seem to have serious problems..
On my 725 restoration, the 3X 470k off the A1 pots were u/s also a couple of the A1 pots.
Thanks Malc I'll check them tomorrow. I haven't tried adjusting the A1 controls. I am going to check the final Anode volts to make sure the EHT isn't excessive before I run it too long!
Hi Lloyd we're not out of the woods yet! I bet this was a really nice set before the mice made a condo out of it... 🤮
Chris, Yes! Rat Phoenix ! Used to be in Corrie years ago?
The areas I expected to be trouble, line osc, Timebases and EHT so far seem to be OK. I was half expecting it to blow the fuses and give off smoke! Anyway, lets not speak too soon! Once I am happy that it is safe to run it I'll make some further checks.
Despite the state of the speaker I do have sound... No Bass but sound nonetheless!
That’s looking promising!
Well done for persevering with it!
Further poking about today 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 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!
I dismantled the button assembly and cleaned the board and contacts, I very fiddley job! The set would then tune 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?
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 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 not too bad. 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.....😉
Today 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. But it is getting there!
Rich
Well done, this is coming on a treat. Have to admit at the start I thought it was beyond redemption. Full marks for having faith and carrying on with it.
John.
Second that! Good to see these early Deltas being brought back to life.
What were the build dates of that chassis series, out of curiousity?
@jayceebee To be honest John so did I, My thoughts were to nick the tube for a Decca 30. I had a fair idea that the tube would be OK as these Mullard red label ones usually were. It absolutely stank when I first got the set and was full of grot so I had to clean it out anyway. Then I decided to have a go at getting it going.
I soon realised the drawer was beyond saving and I thought there was a good chance the LOPT would die as it had been p1$$ed on! However after Chris offered me a drawer and I got a spare line board just in case. (so far not needed, fingers crossed!) I decided to pursue it. It has been ongoing between other little projects since August. The original drawer was just a paste of rust and pee in a plastic box!
It took a fair while to work through the panels but seemed to come together fairly fast as it went on. Still some work to do and I need to find a replacement thick film.
@irob2345 This series was late on in the delta Gun series. 20AX was on the cards and there was a similar higher end model with a 110 degree (albeit still delta) tube. I think this model was made as a budget model it replaced the hybrid sets in I think about 1975 and was superseded by the G11 in 1977. This model is a late one as it has the modifications that the later sets had. Hi stab resistors in the Tube heater circuit being a very late in the series mod.
So, in late '73, when the Oz Pye engineers visited UK (after having been to Toshiba in Japan) they would have seen hybrids?
All I know is they came away saying "we can do much better". (That's what all design engineers say so hardly surprising!!)
They also said that about the Philips K9. Too complex, too expensive.
Because Pye launched with the 110 degree in-line Toshiba CRT, they used the E-W modulator from the K9 which gave better geometry than Toshiba or NEC were getting from a transductor with this tube. The chroma circuits were probably based on UK Pye, the linear power supply on Toshiba and the rest on their existing B&W practice. No plug-in modules, just two wing PCBs, like the K9.
The T29 was probably the most trouble-free of the first generation CTV releases in Oz.
There was a definite art to setting up those early in-line tubes! They could make beautiful pictures but only when set up right.
@irob2345 It is strange that many manufactures made completely different chassis' for different countries even though the line system and receiver areas were very much the same. I know there was some common chassis especially during the 'boon' years in Britain. Maybe it wasn't cost effective to produce a common design in different factories in different parts of the world?
It is also interesting to see how different designers came up with a design for a colour receiver. In the early days most sets were broken down into replaceable modules to help engineers who were unfamiliar with colour to perform repairs.
That plug in a panel idea came in many different designs though Decca 30, Thorn 3500, GEC Hybrid and Solid State, Pye Hybrid and of course the G8. Why did Thorn go to all that trouble to develop 60 Volts for instance? They could have just used a BU208...
Designs changed rapidly as technology changed (I won't say advanced!) It is a wonder anyone made any money having to keep changing the production lines and techniques, especially Philips! Once the G11 finished there seemed to be a multitude of different chassis.
@slidertogrid The Thorn 2000 chassis, dual standard, their first into the colour market at the start of 1967.
I think the reason for the 60volt line was that the design was a collaboration between Thorn and Texas Instruments for the transistors. An all transistor CTV was a milestone in 1967. The SS 3000 chassis probably carried on in the same way after all the development of the 2000.
The BU208 was quite a while after, 1969 saw the BU105 line output transistor and the RBM chassis of 1969 used a pair in totem pole to get around the voltage problem.
Perhaps it’s not too surprising that given the same brief engineers would come up with a completely different idea to solve the same problem, as you say wasteful but perhaps they were thinking of protecting their livelihood.
I find it really interesting seeing the different ways the same problem was solved.
Frank
@nuvistor That's very informative thanks, I changed many in the G8 and a few in the 823, the balance coil was sometimes a bit cooked. In around 1977 I bought a 25" A823 very cheap that had a large, dark picture because the shop thought the tube was clapped. They failed to see the fact that it was too big! To be fair they weren't RBM dealers. I like the 3000 and 3500 despite the some would say unnecessary complexity. At least they didn't go down the route of Thyristors and great big coils! 😉
Rich.
The BU208 was quite a while after, 1969 saw the BU105 line output transistor and the RBM chassis of 1969 used a pair in totem pole to get around the voltage problem.
Straying into the professional realm briefly, the Link 110 camera used two BU104s in its SMPSU for the reasons you outline (IIRC they were also used singly in the Melford DU1 b/w monitors). They were known as "good Union members" on account of if one failed, the other did too - "one out, all out!". Link built a special test jig for repairing them: a colleague had a dead pair soldered together on his keyring. The later 120/125 used a single BUX80.
