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

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crustytv
(@crustytv)
Vrat Founder Admin

Hi Keith, marvellous, I can't thank you enough for your kind assistance. 👍 I'll not use the EY or PD though, they're gone, and I don't want them back.

Now all I need to do is find an ITT LOPT, despite having countless spares for ITT's, I've not one single LOPT. I'll go hunting, already checked Donberg and Mark Hindes, but I'm sure it will be easier to find one of those opposed to a G6 LOPT.

Topic starter Posted : 21/05/2021 12:02 pm
Doz
 Doz
(@doz)
Noble V-Ratter Registered
Posted by: @crustytv

Hi Keith, marvellous, I can't thank you enough for your kind assistance. 👍 I'll not use the EY or PD though, they're gone, and I don't want them back.

Now all I need to do is find an ITT LOPT, despite having countless spares for ITT's, I've not one single LOPT. I'll go hunting, already checked Donberg and Mark Hindes, but I'm sure it will be easier to find one of those opposed to a G6 LOPT.

Does that lopt have any common numbers on it?... I have a few ITT-looking loptx's in the box, all un-identified. 

Posted : 21/05/2021 12:09 pm
Till Eulenspiegel
(@till)
Famed V-Ratter Registered

To avoid the requirement for the 300V anti-phase reference pulses for the G6 flywheel line discriminator,  the circuit could be modified to the design of the relatively simple line sync discriminator circuit in the KB CVC2.

Till Euelenspiegel.

Posted : 21/05/2021 12:40 pm
ctc15
(@ctc15)
New V-Ratter Registered

Hi That looks like a good idea if my G6 bitsa LOPT goes up in smoke. In the Murphy it only needed one pulses winding which was a bit low and  needed  a few more turns to get the colour decoder working. 

The CVC-2 LOPT looks Like a Bradford LOPT .

The Bradford LOPT is a AT2055 the Itt is a AT2055/02

Keith

Posted : 21/05/2021 1:19 pm
ctc15
(@ctc15)
New V-Ratter Registered

Now if Thorn had made a valve colour TV with Jellypot LOPTs would we have all this FUN?

Keith

Posted : 21/05/2021 1:36 pm
crustytv liked
crustytv
(@crustytv)
Vrat Founder Admin

Although I have Bradford lopt's, they're all Red spot (20kV), I got them to keep my families first ever CTV going, the long sought CS1830. I suspect one of those won't be enough, I need Blue spot (25kV) or a CVCx Lopt.

Topic starter Posted : 21/05/2021 1:55 pm
crustytv
(@crustytv)
Vrat Founder Admin

I'm not wanting to reinstate the EY51 or the PD500, so the question is will Keith's modification cct work with those omitted as shown below.

Keith's Original

CVC5 9 G6LOPTConv

Without EY & PD

loptconv
Topic starter Posted : 21/05/2021 9:19 pm
Jayceebee
(@jayceebee)
Noble V-Ratter Registered
Posted by: @ctc15

Now if Thorn had made a valve colour TV with Jellypot LOPTs would we have all this FUN?

Keith

Well there was possibly the mysterious 1000 chassis which was apparently all valve. I think Till said it may have used 2 x PL500s.

Posted : 21/05/2021 9:34 pm
Katie Bush
(@katie-bush)
Illustrious V-Ratter Moderator

Well now, things are looking up!

I might also suggest as an aside to all of this, that it could be handy to have some form of power monitoring device on the mains supply? Thinking back to the growling Iso-TX, a power monitor, something like the ubiquitous "Kill-A-Watt" - I have an alternative version, which is useful in identifying when a device/appliance is drawing excessive current even when all else appears normal. It can save valuable kit from being destroyed. About £10 each from eBay, and can monitor Volts, Watts, Amps, and Hz, displayed on an LCD (Though not all simultaneously).

It's just a thought, and thinking back to Chris' earlier comment about about the heat in the workshop, with the G6 running, made me think, and I wonder now if that might have been a portent to the demise of the LOPT. Perhaps monitoring the power consumption of the set as it is being worked upon, could give valuable prior warning?

Posted : 21/05/2021 11:24 pm
irob2345
(@irob2345)
Reputable V-Ratter Registered

It's like the hero of the story has been struck down with an incurable disease just after he's won the girl!

What you seek is called a Dim Bulb Tester. A politically incorrect  incandescent lamp placed in series with the mains.

For early colour TV work, the "bulb" needs to be 500 watt or thereabouts - maybe two of them in parallel. Heat lamps such as are used in bathrooms work well.

Incandescent lamps are very effective fast-acting PTC thermistors that have the added advantage of being a very obvious fault indicator.

I'd seriously consider a rewind for that transformer. How hard could it be? Polyester insulated winding wire (not "solderite") and tape are used by transformer manufacturers and it is a relatively simple layer wound affair.

Unless the core halves have been glued together in the usual Philips way with epoxy mixed with glass beads to set the gap.

Posted : 22/05/2021 6:47 am
crustytv
(@crustytv)
Vrat Founder Admin
Posted by: @irob2345

I'd seriously consider a rewind for that transformer. How hard could it be? Polyester insulated winding wire (not "solderite") and tape are used by transformer manufacturers and it is a relatively simple layer wound affair.

Fairly hard actually, I quote our "Top man" in the UK for LOPT rewinds.

Posted On Radios-TV Vrat FaceBook Group by:Mike Barker
 
This can be rewound. The problem with this type of Philips LOPT, either B&W or Colour is the white cement used to seal the windings at eaither end of the coil. It gets down inside the layers and also makes it a VERY difficult job to track the wires through it to the relevant windings. If it chips off it usually pulls and breaks other wires burried deep inside. It can take many hours to sucessfully unwind it due to this. If you have never tried it with one of these you will never know just how painful the job can be. I have never found anything that will soften it of disolve it.

My three failed examples are baked beyond belief and solid as a rock, as described. Therefore, I'm not prepared to waste time and money on them. I'm proceeding with the transplant assuming I can find an ITT CVCx or Decca Bradford 'Blue Spot'.

Topic starter Posted : 22/05/2021 7:44 am
crustytv
(@crustytv)
Vrat Founder Admin
Posted by: @katie-bush

It's just a thought, and thinking back to Chris' earlier comment about about the heat in the workshop, with the G6 running, made me think, and I wonder now if that might have been a portent to the demise of the LOPT.

Hi Marion, I think you're reading far too much into that statement. The G6 regardless of state, was by all accounts I've read, a hungry beast and produced a lot of heat.

What I referred to with my comment about the heat in the workshop, was this, and I'm sure I mentioned it at the time. The workshop which is  40ft, and as a result I put in two very large storage heaters, mainly for the collection but also my comfort. Its pretty much at a constant 23/24C, though depending on the outside temp, it may be much warmer.

The G6 which was already known by many in the trade as a "workshop heater", just added to that on the few occasions when I was sitting right behind it taking readings. The longest the TV was ever on was maybe 20 mins, mainly it was 10 mins, tests, then off. Also, you mustn't forget the reputation of the Philips G6 lopt, that of being flakey, even back in the day. It's not me making it up or dissing the G6, tales are plenty in "Television", from TV engineers I've spoken too and many  more accounts on forums. Chris "The Teleman", had the other G6 that came out of the same barn as mine, his primary went the same way after an hour or so. No other reason, no underlying fault, just a plain and simple failure, as was mine.

That finally brings me to the growling ISO/TX, this only happened when the G6 TX primary failed and was drawing excess current. Prior to this event it and the G6 were happily purring along.

Having said all that, one of those "Kill-A-Watt", inline monitors you mention would be very handy. Those of you that perhaps follow a chap called Shango066, will have seen he always uses his when resurrecting his Vintage colour TVs. I've just bought myself one. 👍 

I do have a Lamp Limiter, but stopped using it and buried it away long ago, reason being nearly all the TV's I was working on at the time with switched mode, objected to it as would SYCLOPS, IPSALO1 & 2. Must admit I'd totally forgotten about it and that the G6 would probably have been OK with it.

Topic starter Posted : 22/05/2021 8:09 am
Katie Bush
(@katie-bush)
Illustrious V-Ratter Moderator
Posted by: @crustytv

Hi Marion, I think you're reading far too much into that statement. The G6 regardless of state, was by all accounts I've read, a hungry beast and produced a lot of heat.

Hi Chris, not at all. I was just thinking aloud as it were. If you'd ever had two of these on soak in the middle of July, you'd come out of the shop 'char-grilled'! The power consumption of a G6 was rated by Philips at 500W - And I'd say that was a conservative rating at that. Even in Winter, a single G6 could make a big difference to the comfort, or not, of the shop.

My thinking was that if the set was drawing say, an extra 100W, or even 50W more than it should, it could still be a useful clue that all is not well. Even with the storage heaters keeping your tea hot, it only needs a little bit of extra heat to be noticeable. A 100W lightbulb could keep the bench area nicely warm in Winter, and uncomfortably warm in Summer.

Now then, the Kill-A-Watt. I came to the conclusion that a "HOPI" power monitor would be the perfect workshop companion, since it can monitor all the same parameters as the Kill-A-Watt, but simultaneously. Needless to say, HOPI is like rocking horse droppings, but from watching videos from BigCliveDotCom (electronics and teardowns in general), and from James Condon (generator rebuilds etc) I came to the conclusion that Kill-A-Watt could be as handy as HOPI for my purposes, but Kill-A-Watt didn't seem to be available in the UK when I bought mine, so on recommendation from Clive, I bought the alternative version, which he described as being "Surprisingly good, and using a dedicated chip for monitoring the power and computing the figures......". I'm certainly not disappointed with mine - It can monitor down to mW and mA, ie, my mobile phone charger, and tell the difference between the phone connected, or not connected. You can tell precisely when the phone charging actually stops!

Did I mention it can also display 'Power Factor'? - You should see some of the atrocious figures from LED lamps. Perhaps not important now, but as/when the power companies begin to charge for "Apparent Power" it's going to hit the consumer in the pocket. Incandescent bulbs, PF=1 (Unity). LED bulbs, PF=0.35 to PF=0.6, typically. Some are much worse, but that's another story........ Enough on that.

 

Posted : 22/05/2021 4:26 pm
crustytv
(@crustytv)
Vrat Founder Admin

In response to the LOPT conversion below, the following question was posed on our FaceBook group, afraid I've no idea. Maybe folk here or perhaps Keith, can explain.

Posted On Radios-TV Vrat Facebook Group by:Christopher Field Moderator, Group expert

Curious, why the 2 x capacitors in series with the tripler? I’ve never come across this in any set previously
loptconv
CVC5 9 G6LOPTConv
Topic starter Posted : 22/05/2021 6:44 pm
Till Eulenspiegel
(@till)
Famed V-Ratter Registered

Hi Chris,  if it was my set I'd use the GEC 2040 line output transformer. It's a transformer with an excellent reliability record. However, like all the suggested substitute transformers it does not have -300 and +300 pulse windings for the flywheel line discriminator circuit.  Modifications to that part of the receiver would be necessary anyway. 

Till Eulenspiegel.

Posted : 23/05/2021 12:21 pm
Jayceebee
(@jayceebee)
Noble V-Ratter Registered

I've looked at several transformers and for scan, convergence and EHT many seem to be quite suitable apart from the pulse windings. Here's my idea of possible use of a PYE 693/7 8Kv LOPT, if a CVC5 or 9 is not forthcoming then alternatives will have to be tried. As all CTV's from this era tended to use basically the same scan and convergence coils it makes life a little easier unlike Tills exploits with his 21TG100 Philips mono set. I've attached a circuit for using the PYE 697 LOPT, the only possible bugbear is the fact that pin 3 is grounded. If the ground connection can be removed then is should be possible to use. The PYE LOPT also has a separate winding for DC injection into the scan path for line shift, the G6 has it's own arrangements and this unused winding might be useful in the quest for suitable pulses.

The most problem pulse feedbacks are for the discriminator diodes, might be possible to adapt to the PYE method. I suspect the PYE with some resistor changes can drive the clamp and chroma, but for blue lateral and the supply for the cutoff pot we will have to get inventive.

Anyone see anything I've got wrong or missed?

PYE V1
pye orig
Posted : 23/05/2021 3:12 pm
ctc15
(@ctc15)
New V-Ratter Registered

Hi the capacitor to the Tripler is to block  DC so the negative output to the PD500 and beam limiter can be used so omit them and the connection to the PD500 the Bradford LOPT is almost the same.

(See the Bush ctv25 Mk3 line output diagram.)

Keith 

Posted : 23/05/2021 5:26 pm
Till Eulenspiegel
(@till)
Famed V-Ratter Registered

Are there any variants of the AT1022 scan coil assembly such as /01, /02 etc?

Posted : 23/05/2021 6:05 pm
Jayceebee
(@jayceebee)
Noble V-Ratter Registered

I seem to recall 26" sets used a different version of the AT1022 but don't recall the suffix. I can't say I ever saw them used in any 17/18" models.

Posted : 23/05/2021 6:36 pm
crustytv
(@crustytv)
Vrat Founder Admin

Just when the "All Clear" had sounded, Just when you thought it was safe to venture out, no this G6 thread refuses to lie down and quietly die.

The plan? As I haven't any ITT CVCx nor a 25kV Bradford LOPTs in stock, I'm pressing ahead with Johns idea of using the PYE Hybrid LOPT, I have a NOS 697 in stock.

The plan today is to use a spare, shorted G6 primary I have floating around for its Plugs and loom. I'll wire up the PYE as shown below and make the necessary component changes as per Johns map below and then test to see if I get a scan/raster. We've yet to work out the pulse windings 1 -5.

 

20210525 093925
PYconv1
Topic starter Posted : 25/05/2021 9:47 am
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