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Bush TV125 etc LOPT.... Wanted dead or alive !  

 
PYE625
(@pye625)
Famed V-Ratter Registered

Long shot, but if anyone has one spare in any condition, the overwind in particular, it would be much appreciated.

To understand the black art of electronics is to understand witchcraft.
Andrew.

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Posted : 27/05/2018 1:14 pm
Alastair
(@alastair)
Reputable V-Ratter Registered

Have you tried cooking gthe original on 25-30V dc for some hours?

 

The pitch will bubble and a little will leak out, but eventually after about 4-5 hours, it stops bubbling and its dry.

Put it on an old plate or something like that, the pitch sticks like summit else to a blanket to whatever it gets onto!

 

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Posted : 28/05/2018 6:42 pm
PYE625
(@pye625)
Famed V-Ratter Registered

Hi Alistair, that has all been done and it has been used in a set for several hours. It has also been partly dismantled and the insulation improved (as per the "Bush/Murphy Lopt" title in "Service" above). No, the problem with this one is not of high voltage leakage, but of uneven compression of the picture on 625 lines only (see my Bush TV135LU thread). I think the overwind has been damaged by flashover internally, plus a possible movement of the windings, so the coil is inefficient at the higher line speed.

It is unlikely that anyone has any scrap ones lying around that can be repaired, but is worth asking anyway lol.

IMG 4366 50

To understand the black art of electronics is to understand witchcraft.
Andrew.

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Posted : 28/05/2018 6:49 pm
Alastair
(@alastair)
Reputable V-Ratter Registered

Ah--OK....

So, Is it a linearity type fault on 625? is the 625 compo winding OK?

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Posted : 28/05/2018 8:08 pm
PYE625
(@pye625)
Famed V-Ratter Registered

I believe it is as I swapped only the overwind from another transformer and all was well.

To understand the black art of electronics is to understand witchcraft.
Andrew.

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Posted : 28/05/2018 8:15 pm
BRC 3000
(@brc_3000)
Busy V-Ratter Registered

Hi Andrew , I have a couple of TV125 loptx removed from scrap sets years ago. you are welcome to one if you want one, they are in unknown condition.

Dave

Facebook - uk vintage television collectors

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Posted : 05/06/2018 8:51 pm
PYE625
(@pye625)
Famed V-Ratter Registered

Hi Dave, that is great news !  Thank you...I'll send a PM.

To understand the black art of electronics is to understand witchcraft.
Andrew.

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Posted : 05/06/2018 9:10 pm
PYE625
(@pye625)
Famed V-Ratter Registered

The LOPT from BRC3000 kindly arrived yesterday (thanks Dave), but it would appear to be from a Bush TV115 series and is slightly different. However, I am certainly not complaining as it looks to be in good condition and I will keep it intact for future use if required. Not only that, it also came with an EY86 thrown in for good measure too !

It is interesting to note the use of a thick rubber sleeve between the overwind and the tuning winding, certainly better than the TV125 LOPT insulation.

IMG 4429 50
IMG 4428 50

To understand the black art of electronics is to understand witchcraft.
Andrew.

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Posted : 12/06/2018 5:56 pm
Nuvistor
(@nuvistor)
Famed V-Ratter Registered

Keep the LOPTX somewhere dry and it may well come in handy.

Frank

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Posted : 12/06/2018 7:49 pm
PYE625
(@pye625)
Famed V-Ratter Registered

Very true Frank, I will indeed. Lopt's are like gold dust these days.

To understand the black art of electronics is to understand witchcraft.
Andrew.

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Posted : 12/06/2018 10:06 pm
Katie Bush
(@katie-bush)
Famed V-Ratter Moderator

A useful tip....

Seal up the LOPT in an airtight box, with a layer of "kitty litter" in the bottom. Seal the box with vinyl tape to make sure the air can't get/breathe in, or out. The kitty litter will absorb any moisture inside the box. Better yet, if you can find some silica gel sachets of the sort you sometimes find shoe boxes and electrical equipment packing. In either case, oven dry the absorbent material for an hour or so before sealing up in the box.

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Posted : 13/06/2018 11:04 pm
PYE625
(@pye625)
Famed V-Ratter Registered

Hi Marion, well the workshop is warm and dry, I have a de-humidifier running all the time it is shut up and it always stay's at a low humidity.

At some point I will do a ring test on this LOPT and hope one day to find a Bush TV115 to try it in.  ? 

To understand the black art of electronics is to understand witchcraft.
Andrew.

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Posted : 15/06/2018 4:49 pm