Sony 8-301E Repair

[Electricical]

Greetings People of the Internet!

I got this TV set at an Austrian flea market for about 30€ about two years ago, but it has simply served as a bookend until now. I decided that I would try to fix it this summer.

The cord has a weird 4 prong thing going on, but I stuck my regular shaver cord onto the contacts and that seems to work just fine. I did make sure to plug it onto the 220V prongs, and not the 12V ones, no worries. Before turning it on, I checked to see if the transformer was giving out 12V properly, which it was. (Though, I admit, I only checked the alternating current straight out of the transformer, perhaps I should check if it really does output 12V DC as well.)

The set did not turn on, but it did make some television-like sounds. It sounded like the kind of high frequency noise you would expect from an analogue TV, except, I feel like I could actually hear the cycling, and it sounded too slow. However, the speed of this oscillation did start increasing, if I played with both the HOR and VER dials.

I have some experience with old tube radios and a little bit of an electronics background (having attended one semester of electrical engineering). I found a wealth of information at: https://antiqueradio.org/Sony8-301WTelevision.htm This was also where I found the full manual, which is excellent.

I decided I would follow Philip Nelson’s advice and start looking at the capacitors. Unfortunately, I do not have an ESR meter. The four large filter capacitors tested largely within spec, and the smaller ones largely did not. At this point I decided that investing in new electrolytic capacitors and just replacing them seemed like a sensible idea. I have already ordered new ones from Farnell and they should arrive within the next couple of days.

If the CRT itself is faulty, then there is really nothing I can do, from what I can tell. Of course, I hope that it won’t be. Once the new capacitors arrive, I plan to start recapping the horizontal and vertical sweep board, plugging it in and seeing what happens. And then the rest as well. Sorry for not posting any interesting photos.

Any advice in particular that you have for me? I will keep you updated on the project as it goes along. Thanks!

[Mr Hoover]

Hi,
I restored several of these TVs
including one that came coincidentally
from Austria about 10 years ago.
You're going in the right direction replacing the electrolytics on the sweep board first.
It's not the easiest of TVs to work on.
If you have a 12volt bench power supply and are in any doubt about the AC side use that and feed in on the other two pins of the 4 connector socket.
CRT is unlikely to be bad though maybe a bit low emission.
I've often found the horizontal oscillator is way off frequency,the PCB presets are often in a bad way,one for this is at the side
of the board(other side is wirewound line drive control,normally ok).
Good luck.

[Electricical]

Hello,

nice, thank you. I will make sure to do that, once I get somekind of an image.

[Electricical]

Time for an update.
The capacitors arrived in the mail. I replaced all of the electrolytics on the Horizontal and vertical sweep board, except one which was different from my schematic. The others I have not yet installed. However, it hasn't made any difference at all, so the problem must lie somewhere else. I shot a brief video: https://www.youtube.com/watch?v=g96l...ature=youtu.be
I noticed that something starts to crackle and pop inside if I turn one of the pots way up. It definetly doesn't sound good. Anyone know what that could be?

I did also notice a regular capacitor that was botched on onto the underside of the board that only hung on by one leg. I'm not sure if it got detatched previously of it I did it, but I'm really not sure where I should attach it back to... does anyone have a clue?

What would be the best thing to do next? Should I be checking for shorts or something to that effect?

Thank you very much.
All the best

[Mr Hoover]

The vertical " noise" is about right,it shows that vertical sweep/deflection circuits are
working and the pot in the middle of the
range is about right.
Horizontal is more concerning as to why you see no image, though at least you have
EHT voltage from the sound of that cracking.Leave the horizontal hold control mid range for the moment.
Is the EHT lead from the transformer
on the deflection board connected to the CRT ok?
Brightness control should be mid to 3/4 max
(Clockwise direction)for the moment
Check first of all,is the CRT heater
glowing? Visible just near the CRT
base socket as an orange glow.
The yellow wire from the CRT base should go to a pin on the middle board,this is the video feed,if disconnected you'll get no brightness from the CRT.
I'm not hearing any white noise from the
speaker..contrast control should be at max clockwise,does noise appear then?
The volume control should be turned up for
this(middle board)
Even for experienced repairers this model is still a challenge, poor access,early transistors,quirky circuitry.
That cap is very likely original,it goes across the red and blue
line scan coil connectors,seemed to be individually selected to give best picture width.The colours of the scan coil leads
are marked with letters by the pins, confusing symptoms if
connected wrongly,mirror image, upsidedown or a sideways postage stamp size image!
The set should work with the cap off though the width may be
narrow.
Good luck!