ANYONE with CRT TV REPAIR experience NEEDED

Thread Starter

Just me1

Joined Sep 3, 2017
59
Hi reader,

I have bought an 1965 radio and a 1980 tv radio cassete combi travel tv thing
It was cheap but the radio works, and on the combi only the radio works.
the problem ( you might have guessed it ) is the tv.
When i switch from radio to tv and back rapidly, sometimes a white dot appears in the center, and if i switch back to tv ( VHF ) it fades and turns into a horizontal line, and then fades again and will do nothing.
now if i go to another function like radio and back to vhf it will flash one of those stars you get when you turn off tvs.

so the tv just wont stay on long enough.

and if it helps, the tv sometimes makes motorcycle noises

But those noises come fom the speaker
 
Last edited by a moderator:

AlbertHall

Joined Jun 4, 2014
10,230
It seems like you have some line output as you have HV, but no field scan.
First you need to make sure the power supplies are OK. Unless the PCB is marked to make that possible you're gonna need a schematic.
 

Thread Starter

Just me1

Joined Sep 3, 2017
59
It seems like you have some line output as you have HV, but no field scan.
First you need to make sure the power supplies are OK. Unless the PCB is marked to make that possible you're gonna need a schematic.
power supply was my first thought, and schematics cant be found, it seems this thing is so rare you wont even find a manual

but yea. Im going to check the power supply later this day becouse it 00:30 here
 

#12

Joined Nov 30, 2010
18,210
I see both your horizontal and vertical scans are missing. In some old TVs the vertical driver got its +450VDC from the horizontal section so what looks like 2 problems might be one problem. Find out why the horizontal section makes KV for the CRT but does not drive the yoke with a horizontal scan.

The motor sounds are a different problem.
 

MrChips

Joined Oct 2, 2009
21,650
I believe the problem is that old 1980 TV needs an analog broadcast signal to function.
I don't know if there are any analog TV stations left still broadcasting anywhere in the world.
 

AlbertHall

Joined Jun 4, 2014
10,230
I see both your horizontal and vertical scans are missing. In some old TVs the vertical driver got its +450VDC from the horizontal section so what looks like 2 problems might be one problem. Find out why the horizontal section makes KV for the CRT but does not drive the yoke with a horizontal scan.

The motor sounds are a different problem.
There is mention of a brief horizontal line.
 

AlbertHall

Joined Jun 4, 2014
10,230
There is mention of a brief horizontal line.
That is a good reason for no picture but I would expect a screen full of snow if that was the only problem.

[EDIT] Sorry. That was meant to be a reply to MrChips on the lack of analogue transmissions.
 
Last edited:

MaxHeadRoom

Joined Jul 18, 2013
21,201
Horizontal line is the vertical scan failure.
Oscillator or output.
The common problem of TV's of that era is the power stage electrolyte's.
The 'motorcyle' noises may be an indication of this.
Max.
 

Alec_t

Joined Sep 17, 2013
11,513
Failed electrolytics may well be the culprits, but if there's no analogue TV transmission around is it really worth trying to repair the set?
 

spinnaker

Joined Oct 29, 2009
7,835
Horizontal line is the vertical scan failure.
Oscillator or output.
The common problem of TV's of that era is the power stage electrolyte's.
The 'motorcyle' noises may be an indication of this.
Max.

See if you can pull an arc off of the anode cap on the horizontal oscillator. Should be one of the few tubes (likely the only one) with a cap and lead wire running out of the top of the tube.

Ground a test lead, connect other end to a screwdriver. Put the screwdriver near the cap.

A schematic would really help to measure power supply outputs.

What is the make and model number? Chances are you will find a schematic online.
 

BR-549

Joined Sep 22, 2013
4,938
You might be able to find a sam's on it. sam's photofact.....they use to call it. But it would be wise to take it to a tv repair shop.........that has a very old tech there. You need an old analog guy....if you can't find paperwork.
 
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