Waking up a Bush TV96.

[mark pirate]

Mark, when you used the current heating, did you heat only the overwind or did you do the same to the primary?

I only passed current through the overwind, in this particular set it is not easy to remove the LOPT, so was done in situ.

I would normally remove the LOPT and give it a couple of hours in the oven, but decided to try passing around 1 watt through the overwind for a couple of days, as others had reported success with this method.
It certainly did the trick with the Pye, I had previously run the set several times in the hope it would slowly improve with use, which proved to be unsuccessful.

Mark

[space_charged]

Thanks Mark, for the details.

I'm doing this to a LOPT at the moment and in situ. I'm using 1 watt but am doing both coils.

Just to add to the details if you know the resistance of the coil, mine is 370 ohms, then:

V = sqrt(R*W)

so in my case V = sqrt(370*1) which is 19.2. [ sqrt is the square toot eg sqrt(9) is 3 ]

I

[Heatercathodeshort]

It should not be necessary to warm up the underwind other than to dry out residual dampness.
There are far less turns on it and breakdown is rare.

The problem with removing the LOPT is DISTURBANCE! Unsoldering the tags can lead to heat travelling into the windings and breaking down tired insulation.

Warm her up in situ. Top cap of PL81 to EY86 anode. John.

[dave walsh]

Going back to your handy explanation of the failed fuse [p4* and 6*] John, I opened up my large trusty Far East Multi-Band large radio recently [it had been in damp conditions for a while]. The 60ma fuse seems to have disintegrated but there's no sign of any fault condition and its working fine now the power can get though. I'm no longer puzzled as well.

Dave W

[linescan87]

After 5 days drying out the LOPT I had the set on this evening for 3 hours, overwind only barely warm and width stable.

Sounds like a success.

John Joe

[mark pirate]

Glad to see drying the LOPT out was a success, please post some photos of the set working.

Mark

[rogerdup]

Hello,
After reading all this, I think I have been very lucky when I found my LV30 without this LOPT problem. The set has been stocked in damp atmosphere I think, regarding the rust everywhere. I remember also a Ducastel 441 lines TV found in a discharge and brought to the club. I simply re-impregnated the LOPT with special varnish.
Sunny day in France.
Roger

[linescan87]

This must surely be the best way to dry out a lopt. The tube has responded well to a bit of use

John Joe.

[mark pirate]

Looks good, the CRT will improve with use. In my experience it takes 8-10 hours to fully wake them up.
I have a working but as yet unrestored Bush TV85, the CRT is really good, Mullard tubes usually are....

Mark