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Project [Closed] 1969 Philips G22K511 Missing I/F & LOPT, Conversion

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crustytv
(@crustytv)
Vrat Founder Admin

Wires now connected to the PYE LOPT via the G6 plugs, all except the pulse windings 1-5, we'll have to figure those out later. For now I can test to see if I get a scan.

20210525 113222

Now just got to figure out how I mount this in the tower of the G6 as its a totally different type of arrangement to the G6, this lopt would have been soldered into a PCB.

Topic starter Posted : 25/05/2021 11:35 am
Lloyd and Doz liked
malcscott
(@malcscott)
Noble V-Ratter Registered

@crustytv Looks like a 693 loptx. PCB mounting. A 691 is a free standing type.

Posted : 25/05/2021 6:04 pm
Jayceebee
(@jayceebee)
Noble V-Ratter Registered

@malcscott I've never seen a 691 or 693 for that matter, repaired plenty of 697s though. The circuit I used from the PT mag was most likely a 693 and hopefully the pin numbers match.

Posted : 25/05/2021 6:28 pm
malcscott liked
PYE625
(@pye625)
Famed V-Ratter Registered

Here is a partial view of a 691 LOPT, in my Pye CT72....

120165=23422 rsz img 1913
Posted : 25/05/2021 6:54 pm
malcscott liked
Jayceebee
(@jayceebee)
Noble V-Ratter Registered

@pye625 Thanks Andrew. So were there two versions of the 691, I always thought it used a 25KV LOPT with GY & PD?

Posted : 25/05/2021 7:01 pm
Katie Bush
(@katie-bush)
Illustrious V-Ratter Moderator
Posted by: @jayceebee

@pye625 Thanks Andrew. So were there two versions of the 691, I always thought it used a 25KV LOPT with GY & PD?

My 691 did indeed use those valves. I have to confess, I had no idea there was a 'tripler' version.

 

Posted : 25/05/2021 7:10 pm
PYE625
(@pye625)
Famed V-Ratter Registered

As far as I am aware, only the D/S CT70/71 (and Ekco/Ferranti variants) used that arrangement. The slightly later S/S version had a tripler. That was then known as the 691 chassis. I stand to be corrected of course though.

Posted : 25/05/2021 7:18 pm
Nuvistor
(@nuvistor)
Famed V-Ratter Registered

Pye/Ekco DS CTV had the 25Kv overwind and GY501\PD500 rectifier shunt stabiliser, LOPTX  3Rd harmonic tuned.

691\693 SS chassis had a chassis mounted LOPTX with tripler, 5th Harmonic tuning, this to try and improve EHT regulation.

697 SS LOPTX PCB type with tripler etc.

Whether there were some models that came between the above with a mix and match I can’t say but we were main agents for Pye/Ekco and those were the only configurations I saw.

The 691/693 sets were ok, the 697 not quite so.

Posted : 25/05/2021 8:52 pm
PYE625
(@pye625)
Famed V-Ratter Registered

I remember when I was fortunate enough to obtain my Pye CT72 I was kind of hoping it would have the GY501/PD500 arrangement at the time... But now, in retrospect, it probably is much less troublesome with a tripler. The words dangerous and unreliable tend to spring to mind with the shunt regulated affair. Great if you have a good supply of LOPT's and associated items, not so without me thinks.

Posted : 25/05/2021 9:36 pm
Katie Bush
(@katie-bush)
Illustrious V-Ratter Moderator
Posted by: @pye625

As far as I am aware, only the D/S CT70/71 (and Ekco/Ferranti variants) used that arrangement.

That could just be my addled mind playing tricks again. I'm probably mixing up the CT70 with the 691? - How similar were they?

Posted : 25/05/2021 10:05 pm
Nuvistor
(@nuvistor)
Famed V-Ratter Registered

The DS and SS Pye CTV’s used the same CDA, Decoder and Frame PCB. The tuner was VHF/UHF on the DS, UHF only on the SS. IF strip and Power/Line stages were different.

The LOPTX gave little trouble in the service life but even BW LOPTX’s give trouble after 50 years so a 25Kv overwind is going to give problems. Rank had problems with the LOPTX, burning Bush was I think coined by LLJ.

Until the solid state sets came out from most manufacturers the shunt stabiliser gave really good regulation, much better than the tripler versions, but more expensive.

 

Posted : 25/05/2021 10:53 pm
crustytv
(@crustytv)
Vrat Founder Admin

The PYE LOPT is in and hooked up (less the pulse winding 1-5).

20210526 143847

All that remains now are the final component changes for C5017, R5037, R5036 and R5040. Then it should be time to power up.

20210526 160733
Topic starter Posted : 26/05/2021 2:43 pm
PYE625 liked
Doz
 Doz
(@doz)
Noble V-Ratter Registered

To the bunker!

Untitled

 

Good luck Chris. 

Posted : 26/05/2021 3:35 pm
Katie Bush
(@katie-bush)
Illustrious V-Ratter Moderator

And now - The moment of truth? . . . . . . . . .

Posted : 26/05/2021 4:19 pm
crustytv
(@crustytv)
Vrat Founder Admin

A bit of an anticlimax, only 11kV and no boost across C5013.

Topic starter Posted : 26/05/2021 7:06 pm
Jayceebee
(@jayceebee)
Noble V-Ratter Registered

Oh dear, that's disappointing. Any sign of A1 volts or line scan on screen?

Posted : 26/05/2021 7:21 pm
Katie Bush
(@katie-bush)
Illustrious V-Ratter Moderator

Right, so at least this shows the concept will work, so now it needs debugging and tweaking to make it sing and dance.

Did the boost cap survive okay? - Ralph did say "Check everything".

I'm guessing though, that the PL509 didn't glow red this time? And the next question is, did it survive okay, or is it worth trying a substitute just in case?

Posted : 26/05/2021 10:07 pm
crustytv
(@crustytv)
Vrat Founder Admin

No, PL509 was the usual normal glow and the ISO/TX was fine too, no growling.

I got boost back, it was a wire error on the lower plug, I'd used a spare DS plug and its wires were different. Wired it correctly and boost came back but still woefully low at 488V even adjusting the new R5040. EHT is still also too low at 12kV. John and I have checked all the wires, and they are correct, just looks like the PYE is not a goer.

I'm now ceasing any further work with the PYE LOPT,  I only went down this route as I didn't have a CVC5/9 or Bradford. I will go with Keith's recommendation as and when I get the correct CVC LOPT for the job.

p.s.

John has asked I try one last thing, and I quote, "Could you try in case it's a winding phase issue on the PYE, reverse the connections to PYE LOPT pins 3 & 5".

I'll try that tomorrow, and as I say if it results in no change, the TV is going back to display until a CVC lopt turns up.

Topic starter Posted : 26/05/2021 10:33 pm
ctc15
(@ctc15)
New V-Ratter Registered

Hi Crusty I can not see why the Pye LOPT will not work as it is almost the same.

What is the grid voltage on PL509 and cathode current ( voltage across R1073 ).

Since you at this stage have no feedback to the line osc check it is running at 15625Hz.

Your connections to 3/ 5 seem to be correct.   

Posted : 27/05/2021 9:33 am
crustytv
(@crustytv)
Vrat Founder Admin

Having as closer look this morning in daylight, I spotted a hair fine wire broken from the PYE LOPT to post 6. This would be tag 12 of the original G6 LOPT. This is very likely the cause of my troubles.

20210527 123210[1]
PYconv1
Topic starter Posted : 27/05/2021 12:39 pm
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