UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Television and Video

Notices

Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc.

Closed Thread
 
Thread Tools
Old 6th Apr 2021, 6:53 pm   #1
Snarf81
Heptode
 
Snarf81's Avatar
 
Join Date: Aug 2018
Location: Rogiet, Monmouthshire, Wales, UK.
Posts: 615
Default Sony Trinitron KV-24WX1U no picture.

Hi all

I was given this set today by an elderly couple, and was assured it was working. I got it back home, plugged it in and all I'm getting from it is sound but no picture, not even the green OSD. When it's turned on, the corners of the screen flash momentarily but the screen just seems dead. I've had the back off to clean out all the dust and dog hair and I have noticed that the tube is lighting at the base, so I'm assuming the tube isn't dead?

Is this a common fault with these models? What should I check please? Bear in mind that I'm a novice with crt tv's and the only test kit I have is a multimeter currently
I'd really like to get this going as it's a nice size and fits in the dark depths of the corner of my living room.

Many thanks.
Attached Thumbnails
Click image for larger version

Name:	20210406_180848.jpg
Views:	226
Size:	21.5 KB
ID:	231082   Click image for larger version

Name:	20210406_180828.jpg
Views:	212
Size:	28.9 KB
ID:	231083  
__________________
Richard
https://youtube.com/user/MrBetamax

Last edited by Snarf81; 6th Apr 2021 at 7:00 pm. Reason: Info added.
Snarf81 is offline  
Old 6th Apr 2021, 7:52 pm   #2
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
Default Re: Sony Trinitron KV-24WX1U no picture.

The A1 diode and safety res can fail , not 100% sure whether on this model or not. Worth a check though.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S
HamishBoxer is offline  
Old 6th Apr 2021, 8:44 pm   #3
jayceebee
Heptode
 
jayceebee's Avatar
 
Join Date: Jun 2007
Location: Durham, County Durham, UK.
Posts: 640
Default Re: Sony Trinitron KV-24WX1U no picture.

Dry joint on the field output IC? especially it the set has been disturbed. Can't remember the type but I think it may have been in the TDA817x family, look for a small 7 pin Heptawatt package IC.

John.
jayceebee is offline  
Old 6th Apr 2021, 9:23 pm   #4
Red to black
Nonode
 
Red to black's Avatar
 
Join Date: Mar 2010
Location: Sunderland, Tyne and Wear, UK.
Posts: 2,473
Default Re: Sony Trinitron KV-24WX1U no picture.

This set has the BE3D chassis fitted, it uses a STV9379 field output chip, IC500.
__________________
I don't suffer from Insanity. I enjoy every minute of it.
Red to black is offline  
Old 6th Apr 2021, 9:42 pm   #5
jayceebee
Heptode
 
jayceebee's Avatar
 
Join Date: Jun 2007
Location: Durham, County Durham, UK.
Posts: 640
Default Re: Sony Trinitron KV-24WX1U no picture.

Thanks for reminding me, same type of package though. Refresh my memory but did the ICC9 use a STV9379FS? I'm sure I remember it from some Thomson chassis.
jayceebee is offline  
Old 6th Apr 2021, 10:10 pm   #6
Red to black
Nonode
 
Red to black's Avatar
 
Join Date: Mar 2010
Location: Sunderland, Tyne and Wear, UK.
Posts: 2,473
Default Re: Sony Trinitron KV-24WX1U no picture.

The Ferguson version of the ICC9 used the TDA8172 no suffix, it was the ICC7/8 that used a TDA8178F, I am fairly sure this became NLA later and was replaced by a STV type chip with a small Mod to do, I will still have this information somewhere but I would need to dig it out, depending on which/whose kit you bought IIRC some had a few extra bits and gave superior performance, ie. one of the cheaper kits gave fold over and linearity problems (from off the top of my head).

Edit: here you go C/O the TV mag

Quote:
#7 Ferguson ICC7/8 Chassis

There have been problems with the supply of field output chips for
use as replacements in these chassis, if you fit a Phoenix Modkit 8F
and find that there is cramping at the bottom of the screen, fit a
2.7V zener diode instead of the 2V zener diode supplied in the kit
It's connected from pin 7 to chassis, with its anode to chassis. If
you fit the new type of TDA8178FS chip made by S.T. Sing and find
that there is still no field scanning, fit a 3.9kohms resistor
between pins 2 and 7 and a 2.7V zener diode from pin 7 to chassis,
anode to chassis. E.O.
__________________
I don't suffer from Insanity. I enjoy every minute of it.
Red to black is offline  
Old 6th Apr 2021, 10:54 pm   #7
simpsons
Octode
 
Join Date: Feb 2007
Location: Harrow, London, UK.
Posts: 1,483
Default Re: Sony Trinitron KV-24WX1U no picture.

The SONY BE-3D television supports their Error Code service aid and in addition there are Sony Service Tips. Unless you have already done so, I would familiarise yourself with the Service Codes and Service Tips.

You will need the original remote control to access the service menu.

Sight of the service manual is necessary before any work is undertaken in order to communicate to members. This is available FOC through the usual provider.

Good luck

Chris
simpsons is offline  
Old 7th Apr 2021, 9:20 am   #8
Snarf81
Heptode
 
Snarf81's Avatar
 
Join Date: Aug 2018
Location: Rogiet, Monmouthshire, Wales, UK.
Posts: 615
Default Re: Sony Trinitron KV-24WX1U no picture.

Thanks for the suggestions, I'll get the back off the TV again later today and look for that field output ic and go over the connections.

Chris,
I've downloaded the service manual and tried accessing the service menu with the remote but as nothing is shown on the screen I can't go any further in that respect.

I'll report back later once I've had another look at it.

Many Thanks
__________________
Richard
https://youtube.com/user/MrBetamax
Snarf81 is offline  
Old 7th Apr 2021, 9:39 am   #9
simpsons
Octode
 
Join Date: Feb 2007
Location: Harrow, London, UK.
Posts: 1,483
Default Re: Sony Trinitron KV-24WX1U no picture.

Hi Richard

Members experience with "stock" faults will be a blessing.

I wonder though if the following can help:

Certain error codes are shown by the LED at the front of the set flashing a number of times.

For example Jungle/chroma no acknowledgement 6 flashes, Multiple devices no acknowledgement 19 flashes.

This is explained on page 29 of the service manual.

Good luck

Chris
simpsons is offline  
Old 7th Apr 2021, 11:47 am   #10
Snarf81
Heptode
 
Snarf81's Avatar
 
Join Date: Aug 2018
Location: Rogiet, Monmouthshire, Wales, UK.
Posts: 615
Default Re: Sony Trinitron KV-24WX1U no picture.

Hi Chris,

Thanks for the info.
There are no blinking led's, when it switched on the standby light goes out as normal.

I'm going to take a look at that field IC later and re solder any dodgy looking connections.

Thanks
__________________
Richard
https://youtube.com/user/MrBetamax
Snarf81 is offline  
Old 7th Apr 2021, 12:08 pm   #11
1955APREN
Hexode
 
1955APREN's Avatar
 
Join Date: Nov 2010
Location: Market Drayton, Shropshire, UK.
Posts: 483
Default Re: Sony Trinitron KV-24WX1U no picture.

Normally if there is Frame fault with these set stby light will flash 6 times
if you are going to check the frame out ic connections it might be a good a
idea to make certain that the boot strap Capacitor is discharged b4 soldering
iron short it to input pin and damage's I/c.
Looking at the Line Output Transformer there are two presets on the back
the bottom one is A1 / Screen voltage Carefully mark how this set now turn it
slightly clock wise , can you now see a dull blank screen please let us know
result
regards Derrick
1955APREN is offline  
Old 7th Apr 2021, 2:01 pm   #12
Snarf81
Heptode
 
Snarf81's Avatar
 
Join Date: Aug 2018
Location: Rogiet, Monmouthshire, Wales, UK.
Posts: 615
Default Re: Sony Trinitron KV-24WX1U no picture.

I've had a look and re flowed the joints on the field output IC but to no luck. Still no picture.

Derrick,
The only pre-set I can see on the LOPT is the one pictured. I marked the position and slowly turned it clockwise but still nothing. I've put it back to the original setting. Hmmm.

Thanks
Attached Thumbnails
Click image for larger version

Name:	16178004118722999080638702380571.jpg
Views:	150
Size:	40.5 KB
ID:	231150  
__________________
Richard
https://youtube.com/user/MrBetamax
Snarf81 is offline  
Old 7th Apr 2021, 3:49 pm   #13
1955APREN
Hexode
 
1955APREN's Avatar
 
Join Date: Nov 2010
Location: Market Drayton, Shropshire, UK.
Posts: 483
Default Re: Sony Trinitron KV-24WX1U no picture.

I think this is wide screen set , are there two focus controls on the tube base
then the on on the lopts as in picture is one I was talking about
are you able to measure voltage's on the 3 cathodes on the crt R G B
also can up cheek the A1 voltage ( be careful with is one you meter might not
like it ) Hamish Boxer in post 2 makes a point about the A1 voltage . As I do not have circuit digram I cannot be able see how this voltage obtained but let us know what any voltage on the crt base are
regards
Derrick
1955APREN is offline  
Old 7th Apr 2021, 5:24 pm   #14
Snarf81
Heptode
 
Snarf81's Avatar
 
Join Date: Aug 2018
Location: Rogiet, Monmouthshire, Wales, UK.
Posts: 615
Default Re: Sony Trinitron KV-24WX1U no picture.

It is a wide-screen set, 24inch screen.

I have a pdf download of the service manual if anyone wants to have a nose at it, and can email it over.

I'll measure the RGB voltages in a little while and post the results.

Where is the A1 diode and safety resistor located please? On the Crt base PCB or the main board?
I'll report back with the voltage readings soon.

Thanks!
__________________
Richard
https://youtube.com/user/MrBetamax

Last edited by Snarf81; 7th Apr 2021 at 5:33 pm. Reason: Info
Snarf81 is offline  
Old 7th Apr 2021, 5:43 pm   #15
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
Default Re: Sony Trinitron KV-24WX1U no picture.

A1 diode and res , normally main panel near LOPTX. When found check with the set OFF.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S
HamishBoxer is offline  
Old 7th Apr 2021, 6:11 pm   #16
Snarf81
Heptode
 
Snarf81's Avatar
 
Join Date: Aug 2018
Location: Rogiet, Monmouthshire, Wales, UK.
Posts: 615
Default Re: Sony Trinitron KV-24WX1U no picture.

The voltage on the RGB on the Crt base are as follows.
R 456v AC. 209v DC
G 456v AC. 209 DC
B 456v AC. 209 DC

G1-2, 0v
H2, 0v
H1, 0v
G1-1, 0v
G2, 0v

Hamish boxer,
The picture attached, is that the A1 diode and resistor?

Cheers
Attached Thumbnails
Click image for larger version

Name:	16178154202041801845304609854096.jpg
Views:	110
Size:	49.8 KB
ID:	231170  
__________________
Richard
https://youtube.com/user/MrBetamax
Snarf81 is offline  
Old 7th Apr 2021, 6:49 pm   #17
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
Default Re: Sony Trinitron KV-24WX1U no picture.

That could well be the diode and res, it is a long time since I replaced those I must add. See what they read (diode on Diode test range) Res on Ohms' range of the meter. The diode type eludes me and I think it was a Sony special possibly.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S
HamishBoxer is offline  
Old 7th Apr 2021, 7:02 pm   #18
Snarf81
Heptode
 
Snarf81's Avatar
 
Join Date: Aug 2018
Location: Rogiet, Monmouthshire, Wales, UK.
Posts: 615
Default Re: Sony Trinitron KV-24WX1U no picture.

Rightio, the diode is measuring 1400 on the diode test setting, the resistor isn't measuring at all. It's just reading 1 on all Ohm range settings.
__________________
Richard
https://youtube.com/user/MrBetamax
Snarf81 is offline  
Old 7th Apr 2021, 8:01 pm   #19
Red to black
Nonode
 
Red to black's Avatar
 
Join Date: Mar 2010
Location: Sunderland, Tyne and Wear, UK.
Posts: 2,473
Default Re: Sony Trinitron KV-24WX1U no picture.

Resistor R830 is a 1k 1W fusible resistor and feeds D809 which is type RGP02-20EG23, this is the A1 (Sony calls this G2) supply on the main board from the lopt as in your picture above.
D809 is a high voltage fast acting type, what used to happen is the HV tends to sometimes track across this diode, usually underneath which you can't see until you remove it from the board. Sometimes you can see what looks like a deep scratch/channel on the body of the diode (underside) where the tracking has occurred this is what causes fusible R830 to go open circuit, rather than D809 going short circuit most of the time.

Replacement of D809 and R830 is the only reliable cure, IIRC it was best to leave the replacement D809 stood off the PCB slightly by a couple of mm ie. not pressed fully flat.
I cannot remember now if Sony later changed D809 to a better type.

Edit: C821 is the decoupler/smoother for the A1/G2 supply, I cannot ever remember that blue disc capacitor ever causing any problems in that position on this chassis, nearly always been tracking across the diode itself as the root cause of R830 going open.
__________________
I don't suffer from Insanity. I enjoy every minute of it.

Last edited by Red to black; 7th Apr 2021 at 8:11 pm. Reason: addition
Red to black is offline  
Old 7th Apr 2021, 8:02 pm   #20
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
Default Re: Sony Trinitron KV-24WX1U no picture.

The diode should read around .6 normally and not convinced the res is a 1 Ohm.Of course possible in circuit readings are throwing up wrong values.
Have a look around the LOPTX and see if you can see anymore diodes , just in case this one goes off to the RGB outputs.
I do not have a circuit or I could identify the correct components for you.

Beat me to it and you do have the correct components and yes , replacement removes all doubts. Not sure whether I still have this diode or not in my old stock.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S
HamishBoxer is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 7:02 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.