Chuck wrote:

On Fri, 14 Jan 2011 09:31:12 -0500, "Michael A. Terrell"
wrote:


Chuck wrote:

On Wed, 12 Jan 2011 14:14:25 -0500, "Michael A. Terrell"
wrote:


"Dave Plowman (News)" wrote:

I wonder just how available were the delay lines needed when NTSC was
introduced? They were quite an expensive component years later.


NTSC delay lines for TV sets were about $3 for replacments in the mid
'60s. I only saw one open delay line and one with physical damage in
40+ years. The open delay line removed the luminanve signal, leaving
only moving colored splotches on a black screen.

Delay line failure was fairly common on certain tube sets in the early
70s. Both the coil opening and, in other cases, the capacitor to
ground opening. Chuck


By then I was working in Broadcast. I'll bet those bad delay lines
were made in Mexico. The capacitor in the early lines was a strip of
copper tape on the core, then a layer of insulation before the coil was
wound. One end was soldered to the ground lug.

Some company in Mexico was using a corrosive flux and not cleaning
the coils properly. When you saw an open coil there was usually a lot of
green where the wire opened. I saw several bad yokes with that failure
mode, just before I left for the Army and heard about a lot of similar
failures from that shop but never any delay lines. They worked mostly
on Zenith, RCA and Motorola, in that order. Some GE, Philco, Admiral
and Sylvania which were about 10% of the total. I repaired stereos & a
few TVs for the other people on base, and bought most of the parts
through the shop I had worked at rather than trying to deal with
wholesalers near a military base.

I think you are right about the manufacture of these parts in Mexico.
In 1971 RCA had a massive failure of their tube color chassis
(CTC38?), after a few months operation , of a color band pass coil.
The symptom was a loss of color sync and the reason for it was
internal corrosion and the coil was manufactured in Mexico. Chuck


I worked on a few CTC38 series after I served, and I wasn't impressed
by the design or the quality of the components. A few years later
Curtis Mathis was selling TVs with an identical design, and apparently
bought the tooling from RCA. A lot of them were dead, right out of the
carton. That was about the time I left TV repair for good, and moved to
idustrial electronics.


--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.