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Old 16th Jun 2007, 4:44 pm   #1
FRANK.C
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Default Tube removal advice please

HI All
This is a chassis out of an Alba set. I don't know which model it is. I will post better pictures of the chassis when I remove the tube.

I am trying to remove this tube so I can work on the chassis. A job I an not looking forward to after hearing all of the warnings about imploding tubes, I have my safety goggles to hand.

I will have to remove the ion trap magnet and the rim band. I think the tube neck will slide through the focus magnets.
What I cant figure out is how the scan coils are mounted as they are located inside the metal support. Are they fixed to the support or to the tube neck?

Your help will be much appreciated.

Regards
Frank
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Old 16th Jun 2007, 5:37 pm   #2
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Default Re: Tube removal advice please

Hi Frank. I would imagine that the scan coils are fixed to the mounting around the tube neck. So you can remove the ion trap and the tube base socket and then after removing the front fixing band and the EHT lead, you should be able to slide the tube forward (very carefully) so that the neck passes through the scan coil assembly. This will remain fixed to the chassis.

Store the tube (face down obviously) on something soft (perhaps an old blanket folded several times). You could also try to find a cardboard box that fits around the tube whilst being stored to offer the neck some protection. Keep it well away from anywhere it is likely to be knocked.

Avoid scratching the tube anywhere particularly on the faceplate as this can cause a stress point in the glass.

Be safe, be careful!!


Rich.
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Old 16th Jun 2007, 6:20 pm   #3
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Default Re: Tube removal advice please

Hi Rich
Thanks for the advice. I have cleaned out a corner in the workshop for it. I was going to place it on some cardboard. I have a blanket that I can use, never occurred to me to use a blanket.
I have a large cardboard box left to one side. Once I get the tube out I will cut down to size to suit.

I hope to attempt to remove the tube tomorrow. I will let you know how I got on.

Regards
Frank
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Old 16th Jun 2007, 6:29 pm   #4
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Default Re: Tube removal advice please

Tubes are tougher than you think as long as you are careful. It may help if you wear some gloves with a grip...oh and make sure that the tube is completely discharged before you start. If the set has not been used for decades then it is not likely to be a problem but if the set was on last week, the situation may be different!

I'm sure you will get on fine....there was a first-time tube removal for most of us!!


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Old 16th Jun 2007, 7:05 pm   #5
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Default Re: Tube removal advice please

Very good advice here from Richard. The Mullard tubes are of substantial build using quite thick glass. The MW43-64/69 has never been a problem.

As suggested for safety, wear some eye protection and if you're worried cover the tube with a thick cloth, hessian sack or blanket as you remove it.
No need for steel helmets and lead boots!
The set should be an easy restoration.
Alba LOPTs were reliable.
Good luck with it.

Regards John.
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Old 17th Jun 2007, 10:43 am   #6
FRANK.C
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Default Re: Tube removal advice please

Rich and John
Thanks for the words of encouragement they do help.

The thoughts of having to slide the tube neck through the mounting while holding and balancing by the much heavier faceplate end sounds a bit daunting without having done it before.

I hope to post later today with either a success or failure story.

Thanks again
Frank
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Old 17th Jun 2007, 3:15 pm   #7
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Default Re: Tube removal advice please

Hi all
SUCCESS.
After removing the ion trap magnet the EHT cable tube base connector. I loosened the rim band . The rubber around the Tube was quite stuck to both Tube and rim band, but with a little gentle persuasion it came away. As I then tried to gently slide the tube forward there was a few tense moments as the mount moved forward with the Tube. The rubber grommet around the mount was stuck to Tube neck. A few gentle movements of the Tube released the neck and the Tube slid forward very easily. The Tube is now resting in a corner of the workshop perched on a old blanket with a strong cardboard box covering all.
.
I have yet to identify the model there was no back cover with the set when I received it. On that excellent site thevalvepage.com there is one that looks exactly like it , its a T524. I have a diagram for this model but mine is a different chassis. The T524 has 19 valves this one has only 17. I have ordered The Vintage TV Service Data CD. There should be more information there.

I have posted a few photos of the chassis.

Thanks for all the help
Frank.
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Old 17th Jun 2007, 6:02 pm   #8
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Default Re: Tube removal advice please

Yes they are tough indeed, a hammer has to have moderate force behind it to go through face, OTOH a small scratch over time is disaster...

Several schemes out there to prevent disasters, laminated face, extra glass clamped on...

At work we give the socket a sharp axial twist, which breaks the neck and lets air in, this to make them safer to handle while taking apart rest of the set.
Naturally this destroys the tube, but we are interested in the actual metals, not restoring/repair, quite interesting things can be found in tubes, Ge, Ce, P and a quite few others, the glass has plenty of Pb...
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Old 17th Jun 2007, 8:28 pm   #9
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Default Re: Tube removal advice please

Well done Frank,
This might seem a simple task to those of us who have been pulling tubes out of sets for years, but the first time you do it, believe me ,you need some advice!

It's when all the others run out of the room that you need to get concerned. You will be throwing CRM151's around before you know it.

Let us know how the rebirth of the Alba progresses.

Regards John.
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Old 17th Jun 2007, 11:17 pm   #10
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Default Re: Tube removal advice please

Quote:
Originally Posted by FRANK.C View Post
Hi all
SUCCESS.
.
Well done Frank . Wasn't so bad was it?. Wait 'till you get one of the Ekco's with a round tube in a cradle...something like the T283. A nice big CRM141 that comes out with implosion screen still attached. You have to take the whole lot out to clean the faceplate...you can't get the implosion screen off otherwise.


Happy days!

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Old 17th Jun 2007, 11:53 pm   #11
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Default Re: Tube removal advice please

HI John and Rich
The fear of the unknown is always the worst.
I am on a steep learning curve here and no doubt I will be posting with in the future with more problems. When/if I get it finished I will post some photos. I suspect that it will take some time.

CRM151, CRM141 Wow - the nerves wouldn't be able for that!.

Regards
Frank
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Old 18th Jun 2007, 8:47 am   #12
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Default Re: Tube removal advice please

I presume the 151 141 are bigger than the 123, which in my set is in a cradle with implosion screen attached. I did find that setup made it easy to handle the tube, but if you needed to remove it from the cradle and coils that would be another matter.
I think you have just to be careful and sensible with handling these things; they are stronger than you think, otherwise they would be going off bang all the time!

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Old 18th Jun 2007, 8:54 am   #13
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Default Re: Tube removal advice please

There. Frank, wasn't too bad, was it?
Watch out for the fine tuner knob on this chassis if it is the one I remember - they were very fragile.

For interest, in the last days of my sojourn at British Relay, the FSEs were expected to change tubes in the customer's house; imagine that with a 26" G6 !!
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