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Bush TV 62 has Very close shave!

 
Alastair
(@alastair)
Reputable V-Ratter Registered

A couple of weeks ago, I was told that the Council have changed policy and that I was to lose my job as a TV repair engineer and be replaced by a domestic-appliance engineer. I was an 'Agency' worker and have no rights or other ties etc to try and remain at the job.

Anyway, a week last friday was my last day. I had got most of my equipment and stuff out, but had left a couple of things I had forgotten.
Last Monday, I call in and to my amazement there's a Bush TV62 on what was my workbench and this guy messing with it.
He was the Domestic-appliance tech, and I explained to him that he should on no account apply raw mains to that set...
Which is Exactly what he DID do, I found out a few days later, and flooded the whole shop/workshop with thick acrid smoke...... :ccb

He then chucked the set as-is into the skip--In The Rain, where it sat till Wednesday . Obviously a total numpty (Sour-grapes at being replaced by this guy?--yes, but to do what he did after being told the dangers--was just plain stupid!) :aai
(Thankfully, we havent had that much rain early on in the week, or it would still be completely soaking.)

It was extremely fortunate that I called on Wednesday and discovered this fact and rescued it, where it was then stored until I could arrange its purchase today.

Ive got the set home today and checked it through, astoundingly it has survived the trip into the skip the case and CRT are still fully intact, just an odd scuff around the front panel. Its only missing part is one screw for the rear cover. Its otherwise fully complete, and looks unmolested--doesnt appear any 'period' repairs have been done either, except some valves are 'non-standard' makes...

Its currently warming through, running the heaters only, Ive pulled the HT fuse and supplying full mains at the moment. I plan to run like this for a good few hours tomorrow, to dry the set as much as possible, then I'm thinking of putting say a 40W bulb in place of the HT fuse,--see what happens.

Ive found that the smoke was caused by the 0.1uF Mains-Filter-cap, a TCC Wax device that had disgorged its guts and badly carbonated, its a wonder it didn't go up in flames!

How many 'lives' do these sets have? This one has used at least two up! :thumb

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Topic starter Posted : 06/04/2014 12:18 am
Lloyd
(@lloyd)
Noble V-Ratter Registered

Hi,
Sorry to hear your about your job, but well done saving the TV62! I'm amazed it survived it's visit to the skip.

Watch out for the big waxie at the back of the timebase chassis, they kick out loads of smoke!

Regards,
Lloyd

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Posted : 06/04/2014 12:35 am
Cobaltblue
(@cobaltblue)
Honorable V-Ratter Registered

Hi Alistair

Call me the suspicious type if you like but a bit of nepotism going on there in my opinion :bbd

Sorry to hear about the loss of your job I seem to remember it was hard won.

It seems down skilling is a way of life these days, we tried it a few years ago ( A few of us stood and said it would be a disaster) and it was a disaster and we are still suffering the consequences ten years later.

Lets hope someone gets a shock ( not electrical ) when the takings are down and they reconsider.

Cheers

Mike T

I don't care if it was a bargain whats it doing on my kitchen table.
www.cossor.co.uk

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Posted : 06/04/2014 9:41 am
Alastair
(@alastair)
Reputable V-Ratter Registered

Cobaltblue--

Would you like to hear the full story? Nepotism, (sort of) The British Standards Institute and bad management cover-ups are all involved--it IS the Council after all!

I'll start a thread in the Lounge section later today--as its quite interesting because it goes Much deeper than the loss of an Agency job!
I'll not clutter this Bush thread with it.

Ive been looking on past threads of Bush 62 and 53 sets, there seems to be a concern about the heaters of the CRT's with these sets.
My heaters are running at 5v in the chain, but the cathode-tube seems completely evenly heated, all be it a little dull in colour temperature--Hoping its OK

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Topic starter Posted : 06/04/2014 10:58 am
mark pirate
(@mark-pirate)
Reputable V-Ratter Deactivated Account

I am glad you managed to save it, what luck that the cabinet did not crack :thumb
They do give a decent picture once sorted, mine only needed a recapping and a clean, not bad after 37 years stored in a garage!

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Posted : 06/04/2014 9:21 pm
Alastair
(@alastair)
Reputable V-Ratter Registered

How is the reliability of the Line-Output transformer on these?

We all know the later Bush overwind troubles, do these suffer the same...?

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Topic starter Posted : 07/04/2014 12:09 am
Duke Nukem
(@duke-nukem)
Reputable V-Ratter Deactivated Account

Judging by the lack of requests for replacement LOPTs I suspect they are no worse than any other set of the period after years of storage. But in this case, even if it is duff, the LOPT is used in a number of more common and less desirable (=cheap) models so you'd have no prob finding a replacement.

Remember seeing one working at Harpenden a few years back - absolutely cracking picture.

TTFN,
Jon

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Posted : 07/04/2014 11:42 am
Alastair
(@alastair)
Reputable V-Ratter Registered

Thats good to hear Jon....

As a precaution, I removed the LOPT, dusted it off and checked continuity. There was none on the secondary/Overwind.
After very careful examination--I may have caused this myself--The earthy end of the overwind is a single strand of pretty thin wire that was tucked up inside the plastic lead-out covering of the primary coil. It was broken.

Carefully, I teased the remaining lead from the surface insulation of the primary, and re-made a joint with some fresh wire to make up the distance. I covered the join in epoxy for robustness.
The resistance now read 382 ohms.

I decided to give it a little warmth--as in that experiment I carried out on the TV125 type pitch coil, but was a bit less aggressive, it being a thin feeble wave-wound disc affair with much less mass to heat up.

I dissipated 7.5W through the coil by running 50V across it. This heated it to around 70 deg C. It was left for 12 hours like this, there was no change in the physical form or appearance of the coil, there doesn't seem to be any wax or pitch involved with these, just a hard black varnish of some type, that did have a few surface cracks on one side that radiated out from the centre, like spokes on a wheel....

While still warm, I coated the coil with 'Ulti-Meg' and left to dry, more to fill the cracks than anything else.

I plan to fit back to the set later and try some juice to the whole set--not just heaters! In the meantime, I must fix a 50" plasma :aac

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Topic starter Posted : 07/04/2014 5:02 pm
Alastair
(@alastair)
Reputable V-Ratter Registered

Last night, I fired it up....

LOPT was re-installed and a 25W lamp wired across the HT fuse which was removed.

I monitored the supply at the first cap in the reservoir and had 57V I could just hear the line-timebase running but little else.
I left the set run and warm through like this for about 10 minutes, nothing horrible happened.

I replaced the lamp with a 60W bulb and HT rail rose to 125V, the line whistle became stronger and there seemed to be life on the sound stages.
Again, nothing horrible happened and I left it run for 15-20 minutes, the main reservoir block remained stone cold.

After this, I thought, might as well give it the full beans and removed the lamp and replaced the fuse.

Fired it up again, line took a little while to come alive, and the EHT rectifier glowed a loverly purple with streamers of blue flame inside, It had gone soft.
Rummage as much as I could, I couldn't find an EY86/7 only several new DY86/7, and a couple of old ones.

Thought--what the hell, and popped an old one in. Again the set took a little while to come alive (I think the PL81 is a bit lazy) then the EHT came up and the DY86 glowed like a light-bulb, but I then had something on the screen--

A Frame Collapse!

Ah--brill, It Is Alive!--well, sorta..... :aaj

As I have so many DY86/7 valves I decided to mod up the heater-supply to the EHT socket so removed the LOPT again and unwound the heater-winding. It had 8 turns.
The EY86 has a 6.3V heater and the DY86 a 1.4V heater.
I unwound 6 turns, leaving 2 which would give still a little too much, but better than light-bulbing the DY86.

Refitted LOPT and tried again. Much better colour of the DY heater, I would say probably normal, so I fitted a new one.
The frame-collapse remained so attention was turned to that stage where several wax-TCC caps were replaced.
I now have a 3/4 frame, severely folded over at the bottom, but good and bright. I left the set run for an hour checking carefully for any overheating or other nasties, it kept running and the fold-over improved just slightly.
There's still loads of waxies that need to go so I'll pull the TB chassis and replace them and check the resistor values..... :thumb

One thing I noticed, The 'ION Trap' magnet is half on the bakelite tube-base and the glass. Tried altering it slightly and improved the brightness a tad, but this does seem to me an odd place for it. I dont know if this CRT has been replaced, there is only one label--which is the one with lots of tiny writing tucked right up near the screen end of the tube, and not the main makers label--Thats gone long ago!

Anyone have this sort of tube, where is the Ion-trap on yours?

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Topic starter Posted : 09/04/2014 9:29 am
Marc
 Marc
(@marc)
Famed V-Ratter Registered

Hi Alastair,

I have a few sets with that type of CRT and the Ion trap mags are partly on the CRT plug as well so it would seem that it's normal for them to be positioned like so.

Marc.

Marc
BVWS member
RSGB call sign 2E0VTN

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Posted : 09/04/2014 1:01 pm
Alastair
(@alastair)
Reputable V-Ratter Registered

Ah--Cheers Marc, Good to know.

Ones Ive seen before were about 1/4-1/2 inch from the base, but they were on a totally different tube.....

I'm going to drop out the timebase chassis later and do some proper work to it,--Mainly waxy-caps I think-- see if I can get the frame-stage performing correctly...

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Topic starter Posted : 09/04/2014 2:21 pm
Alastair
(@alastair)
Reputable V-Ratter Registered

Cureently, I have mains-hum on both picture and sound.

Not massive but enough to cause the picture to undulate somewhat.

As I hadn't done one before, I decided to re-stuff the original can electrolytic--this went quite well, I used some 100uF Nippon-Chemicon, using two in parallel for the 200uF section.

This didn't make any difference at all to the hum....

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Topic starter Posted : 12/04/2014 10:52 am
Alastair
(@alastair)
Reputable V-Ratter Registered

The job I had was actually very nice. I was responsible for repairing and then selling broken TV sets at a shop project that had been set up to re-sell stuff that had been thrown out...

Its amazing the stuff people chuck away! Sometimes, even fully working flat-screens were disposed of there.

I have a great 43" Pioneer plasma set, that was fully working and I bought from the shop!

I did say that I was going to tell the tale of how I was finished at the job, but as I'm fighting to get it back--it wouldnt be right to say much about that on the internet--Yet!

As to the Bush, I'm thinking I may have more issues with the CRT than I first thought. I Think at the moment, I have a leak Heater/Cathode, as the picture will vary in brightness and contrast while the +B rails are constant and reasonably correct.

As the tube heater was rather dim, Ive used a 12V (14V unloaded) Transformer and a 22 ohm resistor in series, but this is still grounded on one side--as was the original design, being the last (first) in the series chain.
The set-up like this, we get 5.6V across the heaters instead of 4.6v when in the chain, and calculation with what is across the resistor leads to the current of 350mA, and a more normal colour temperature of the heater.
Heater dissipation is 1.96 at this value and is just 0.17W more than it would be if correct...

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Topic starter Posted : 12/04/2014 6:12 pm
Terry
(@terrykc)
Famed V-Ratter Rest in Peace

If you have a heater/cathode leak, brightness will be uncontrollably bright due to the cathode being dragged down.

If is still working because it is a slight leak then the isolation transformer will work but, of course, the secondary must be completely floating for it to work, so remove the heater/cathode connection.

When all else fails, read the instructions

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Posted : 12/04/2014 6:23 pm