[sci.electronics] TV Picture Tube Replacement

jaborn@bbn.com (Justin A. Aborn) (08/31/90)

My 13" Sony color TV fell off a table onto its face yesterday.
The picture tube broke at its rear around the electron guns.

I am going to try to replace the tube myself.  How hard are the
convergence, purity, and beam intensity adjustments to make for
the new tube?  Has anyone done this at home before?

I have a VHS tape of a color bar test pattern, and some text
across a screen to pass for a grid and dot pattern.

Am I crazy to try this?

Justin

barry@hprmokg.HP.COM (Barry Fowler) (09/01/90)

You can probably do it at home if you are familiar with the alignment
procedures.  I have done it.

I question the cost effectiveness of doing so, however.  Replacement
CRTs are very expensive as TVs are starting to evolve into "consumable
items" and it is often cheaper to get a new set when major repairs
(like yours) are necessary.

On the other hand... my 1968 Zenith is still working great  :-)

al@cs.strath.ac.uk (Alan Lorimer) (09/03/90)

In article <34590007@hprmokg.HP.COM> barry@hprmokg.HP.COM (Barry Fowler) writes:
>You can probably do it at home if you are familiar with the alignment
>procedures.  I have done it.
>
>I question the cost effectiveness of doing so, however.  Replacement
>CRTs are very expensive as TVs are starting to evolve into "consumable


Brand new CRTs are indeed expensive, however regunned tubes which
these days are safe and cheap have a comparatively trivial cost.

I have replaced a number of tubes 22" Philips G11 A56-550X etc and
some 14" ones. Each tube has cost about #40 sterling to buy and has
taken about 1.5 hours to fit (including line up). 

The problem which the original poster mentioned was a trinitron tube
which I promise him will be a nightmare to fit! Fine tuning of
convergence and purity on these sets is achieved by GLUEING magnets
onto the outside of the bowl. It is not the action of glueing the
magnets which is difficult, but the fact that positioning them
requires the set to be running and access to most parts of the tube
bowl. 

On sony sets, this is notoriously difficult - Sony how do you do it in
the factory. Sony sets to do not take kindly to the idea of running
while in a semi dismantled state, the boards rarely hinge out and
access to the bottom part of the tube is usually immediately adjacent
to the line output transformer/transistor with 27kV ready to arc
accross to the unwary engineer's hand!

If your local TV repair shop charges a premium for mending Sony sets -
pay it willingly - at least they're going to *try* to fix it.

Alan
-- 
____________________________________________________________________________
Alan G. Lorimer, Strathclyde University, 26 Richmond Street, Glasgow G1 1XH.
UUCP: ...!uunet!mcvax!ukc!strath-cs!al    DARPA: al%cs.strath.ac.uk@nsf.ac.uk
Tel. +44 41 552 4400 Ext.  3592		  JANET: al@uk.ac.strath.cs