RCA EGA330s Audio Problem

[Alkemyst]

This message was originally posted over at alt.antiques.radio+phono and
it was suggested it be posted here as well....

I need some help, if I may, with regard to my 1984 RCA TV
(EGA330s). The audio is horrable on it, and has been this way
since i aquired the set about 10 years ago. I saw a post on a >site

that made mention to this model and audio problems, but

required I be a liscenced dealer to see the causes. I was
wondering if anyone on here may know why the audio is so bad. The
video is great, but the audio is crackly and distorted and no
amount of fine tuning will fix it. If you need more information i
can provide it. Im not
the kina guy to go out and buy a new TV if the one I got can be
fixed, and cost effectiveness isnt an issue, its the point of
throwing out old electronics over something simple.

i recieved this responce:

i know the model your talking about, i used to have those roll
through my shop on a regular basis, all with the same problem.
the cause is the ratio detecter coil in the audio section has to >be

replaced as it is not posible to adjust it. i dont know if the

replacement part is still available, however, you will have to >check with a RCA parts distributor.

Does this sound right? Upon his suggestion I have opened the set and
found the following...as posed in the other usenet group:

ok...ive opened the set and had a look. In the actual audio >section I

see 2 coils, they both appear to be adjustable (in not >usre if you
meant they were non adjustable, or just could no >longer be adjusted.)
hey are labeled: Discrim (im assuming thats >the one you are talking
about) and the other is labeled 4.5Mhz >IN. They have blue and pink
tops on them. I know youre working >from memory, so i completely
understand if none of them rings a >bell. But if by some chance do you
remember it being one of these >two? or is it farther up the stream?
The two coils in question >are located on the main chassis board right
behind what appears >to be the audio amplifier IC with a copper
heatsink on it.


are either of these coils the one described? If not where should I
look? thanks all for your advice...its very much appreciated!

Keith

 

[Alkemyst]

P.S. sorry it looks so bad....if you want an easier to read version ill
post this link to the origonal thread.

http://groups-beta.google.com/group...03d672e001b/12cb84279a3a3b17#12cb84279a3a3b17>

 

[Rono]

Around that era there was a quadrature coil
adjustment needed to repair low audio! It's
a tin can with a ferrite tunable adjustmnent!
Should fix it! Rono.
\

 

[Jerry G.]

In many of these older models of sets, the audio detector coil would drift
out a bit. It is a slug tuned coil. In most sets it was in a metal can. You
can tweak it for the best response, when the fine tuning is in the correct
position. Use the proper alignment tool to tweak it. This coil was also
known as the audio-quadrature coil.

--

Jerry G.
=====

This message was originally posted over at alt.antiques.radio+phono and
it was suggested it be posted here as well....

I need some help, if I may, with regard to my 1984 RCA TV
(EGA330s). The audio is horrable on it, and has been this way
since i aquired the set about 10 years ago. I saw a post on a >site

that made mention to this model and audio problems, but

required I be a liscenced dealer to see the causes. I was
wondering if anyone on here may know why the audio is so bad. The
video is great, but the audio is crackly and distorted and no
amount of fine tuning will fix it. If you need more information i
can provide it. Im not
the kina guy to go out and buy a new TV if the one I got can be
fixed, and cost effectiveness isnt an issue, its the point of
throwing out old electronics over something simple.

i recieved this responce:

i know the model your talking about, i used to have those roll
through my shop on a regular basis, all with the same problem.
the cause is the ratio detecter coil in the audio section has to >be

replaced as it is not posible to adjust it. i dont know if the

replacement part is still available, however, you will have to >check with a RCA parts distributor.

Does this sound right? Upon his suggestion I have opened the set and
found the following...as posed in the other usenet group:

ok...ive opened the set and had a look. In the actual audio >section I

see 2 coils, they both appear to be adjustable (in not >usre if you
meant they were non adjustable, or just could no >longer be adjusted.)
hey are labeled: Discrim (im assuming thats >the one you are talking
about) and the other is labeled 4.5Mhz >IN. They have blue and pink
tops on them. I know youre working >from memory, so i completely
understand if none of them rings a >bell. But if by some chance do you
remember it being one of these >two? or is it farther up the stream?
The two coils in question >are located on the main chassis board right
behind what appears >to be the audio amplifier IC with a copper
heatsink on it.


are either of these coils the one described? If not where should I
look? thanks all for your advice...its very much appreciated!

Keith

 

[Alkemyst]

excellant, thank you very much. Ill have a look to see if I can locate
the coil in question. Im sure Ill have many more questions in the
future...ill let you know what I find.

 

[Alkemyst]

ok...ive noticed another thing about the TV that i didnt notice before.
There are interferance lines in the picture that are linked to the
audio of that scene. I didnt npcie it beofre casue i routed my audio
from my DVD through my reciever, but when i hooked it back up i figured
id see if there was any audio inerferance, and there was. Is this still
a symptom of this coil being mis-adjusted?

 

[[email protected]]

I remember those too. I used to adjust them and I seem to remember
blue and red coil forms. Take an alignment tool to the one marked disc
first. I don't remember if there was a top and bottom (primary and
secondary) to this coil. If so your tool will have to be able to slide
in to the top make that adjustment and then slide down to the bottom
section. Put a piece of tape on the tool like a flag. Note the position
of the flag before turning the tool so that you can return it to its
starting position if the adjustment does not change the audio. As I
recall just a slight twist was all it took to clear it up. Anything
related to "disc or 4.5mhz) is in the right neighborhood. Good luck,
Lenny Stein, Barlen Electronics.

 

[Alkemyst]

thanks, ill do that this week. Will adjusting these coils help with the
audio interfering with the picture? also how do i adjust the level that
the color cuts off at. Just over the last month the color cuts off when
viewing VHS tapes, TV and DVD are fine...
Any ideas?

Thanks so much for the help so far guys!!

Keith

 

[[email protected]]

The coil that I was referring to may not affect the picture. I think
you may have other issues if audio modulation is affecting your video.
As far as your color problem if the cable signal and the DVD is fine I
would suspect a VCR problem. Lenny Stein, Barlen Electronics.

 

[Alkemyst]

ok...ill sawp in another VCR and see what happens. Also the slight
picture interferance is fine by me, as long as i can get the audio
cleared up (or do you think both problems are linked?) Ill work on
adjusting the coils this week like i said and Ill let you know the
result.

Thanks again,
Keith