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 19th Jan 2016, 6:07 pm   #1
Chrisw
Triode
 
Chrisw's Avatar
 
Join Date: Aug 2006
Location: Bury St Edmunds, Suffolk, UK.
Posts: 44
Angry Sony TV306 UB

Hi all. Ever wished you had not started something?. My recap of my Sony TV9 306 continues but this little set has to be worst I have ever worked on.
I recapped the Line/Field Timebase board and then like a fool looked at the caps on the IF board not a good idea. I now have a set that with good 405 Audio on any channel selected but not the slightest trace of any modulation on the CRT. If I inject a 405 Video signal (test card C) at the junction of the vision demod diode D304 and L304 I get a really good display so the fault is def in the IF panel. 625 scans ok but of course nothing else , again pointing to the IF panel. I have changed TR501,502 and 503 and replaced them with AF239S which all test ok prior to fitting and have the same pin out as the original 2SA456/5/4 used by Sony.
Can anyone advise as to frequencies I could try injecting at the 3 Vision stages to try and track down this fault and on the final Vision stage , on the collector of TR305 what should I expect freq wise?.(Trader sheet 1803).
I have placed an AD in the wanted section in the hope someone has one of these sets that has been dropped.
As usual any advice appreciated.
Chrisw is offline  
Old 22nd Jan 2016, 9:40 am   #2
Mr Hoover
Hexode
 
Mr Hoover's Avatar
 
Join Date: Jan 2007
Location: Faro, Portugal
Posts: 269
Default Re: Sony TV306 UB

Hi. IFs are standard UK ones, 34.65 fine for 405 signal tracing. Are the germanium transistor voltages ok? Compare with the working ones on the AM sound board.
Also check the relay switching the detector diode from pos to neg video..
I have the Sony manual for the set but will have to locate it.
Good luck.
Cheers
Hugh
Mr Hoover is offline  
Old 22nd Jan 2016, 7:42 pm   #3
Chrisw
Triode
 
Chrisw's Avatar
 
Join Date: Aug 2006
Location: Bury St Edmunds, Suffolk, UK.
Posts: 44
Default Re: Sony TV306 UB

Hi Hugh. Thanks for the reply. I've given the set a break the last few days as it really has made me fed up. When I start on it again I'll record the voltage on the Transistors and get in touch with you. I've looked for the official Sony service manual but with no joy. The only info I have is on the Trader service sheet which only lists one voltage for the Transistors on the IF board.
Once again thanks for the reply.
Chrisw is offline  
Old 22nd Jan 2016, 9:36 pm   #4
Mikey405
Octode
 
Mikey405's Avatar
 
Join Date: Jul 2006
Location: Solihull, West Midlands and Beaford, Devon
Posts: 1,626
Default Re: Sony TV306 UB

Hi Chris.

I think I have the Sony 9-306 manual in my loft so if you can wait until mid-week then I'll find it and scan anything you need out of it.

Thanks Chris.

Kind regards.

From Mike.
__________________
G7TRF
Mikey405 is offline  
Old 23rd Jan 2016, 9:12 am   #5
Mr Hoover
Hexode
 
Mr Hoover's Avatar
 
Join Date: Jan 2007
Location: Faro, Portugal
Posts: 269
Default Re: Sony TV306 UB

Hi again.
Found the manual,not very helpful with voltages and the circuit diagram is quite small..

However some pointers are given,system switch in 625
position.My scanner isn't working,so maybe Mikey could scan something if you need it. Gives detailed realignment and disassembly instructions and some waveforms to be expected.

1st IF transistor (x301 on Sony sheet),volt drop across R306 and R307,both 270 ohms is 0.27v on each,emitter feed resistors from positive supply.

2nd IF transistor X302 base should be 9.4 volts. Volt drop
across R312 base bias resistor 3.9K is 0.36v.

3rd IF transistor,volt drop across R318,750 ohms is 1.6 volts..Emitter resistor from supply.

Nothing else is listed for the IF transistors.

Cheers

Hugh
Mr Hoover is offline  
Old 25th Jan 2016, 7:43 pm   #6
Chrisw
Triode
 
Chrisw's Avatar
 
Join Date: Aug 2006
Location: Bury St Edmunds, Suffolk, UK.
Posts: 44
Default Re: Sony TV306 UB

Hi Hugh.A quick update for you. I had a very good weekend on the set and have made some very good progress with it.I'll post some pictures on the progress in a few days. Thanks again for your advice.Cheers for now.
Chrisw is offline  
Old 27th Jan 2016, 4:56 pm   #7
Chrisw
Triode
 
Chrisw's Avatar
 
Join Date: Aug 2006
Location: Bury St Edmunds, Suffolk, UK.
Posts: 44
Default Re: Sony TV306 UB

Hi Hugh.
As per your advice I checked the voltages around the IF strip finding some wrong and some missing. On this basis I did a detailed check of the whole panel and found two tiny breaks in the pcb tracks, repairing these actually then gave me a very faint and at times distorted Test card on 405 but nothing on 625.
I could find nothing else amiss so with care the IF transformers were tweaked a little and results got better and better. Intially with no RF input on 405 I had just a blank raster and none of the usual background noise expected, as alignment got better this increased, it was the same on 625 and the white noise increased .
Eventually I have ended up with a very good picture on any 405 channel but the 625 performance remains poor. I can get a perfect picture or sound but not together, the tuning must be off set a tiny bit (higher) to give both. There is also some overscan on 625 but I have read that this was the norm for these sets in their day. No adjustment of the coils on the subcarrier part of the IF board improves the 625 performance so its something I will prob just have to live with.
Photos attached are taken with an iphone so not the best. The last one with William Hartnell in is on 625..
Attached Thumbnails
Click image for larger version

Name:	late jan 2016 082.jpg
Views:	184
Size:	82.8 KB
ID:	119053   Click image for larger version

Name:	late jan 2016 080.jpg
Views:	120
Size:	85.3 KB
ID:	119054   Click image for larger version

Name:	late jan 2016 094.jpg
Views:	108
Size:	61.4 KB
ID:	119055   Click image for larger version

Name:	late jan 2016 106.jpg
Views:	111
Size:	30.6 KB
ID:	119056  
Chrisw is offline  
Old 27th Jan 2016, 5:04 pm   #8
pastyboy
Hexode
 
pastyboy's Avatar
 
Join Date: Nov 2015
Location: Cornwall, UK.
Posts: 270
Default Re: Sony TV306 UB

I have never been brave enough to attempt sony gear - tales of woe from engineers with regard to the mid 70's large sets with the funny "devices" that went bang and cost a fortune.

The TV306 looks a fine set though.
pastyboy is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 6:56 pm.


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.