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

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Television and Video
Register FAQ Forum Rules Calendar Mark Forums Read

Notices

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

Reply
 
Thread Tools
Old 6th Jul 2013, 11:13 am   #21
FERNSEH
Nonode
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 2,485
Default Re: Alba t655

I hope this not going to be line output transformer failure. For the fault condition you have described I'd check or replace the PL81 first. Make sure that C47 which is the coupling capacitor between the line oscillator and the PL81 has been changed. Also check the values of the anode load resistors of the line oscillator valve, R60 and R61. R60 can go low in value and R61 high.
Check the boost capacitor C50, 0.1microfarads @1000v. Boost volts are high in this set, 630V. The PL81 screen feed resistor is known to fail. 1.5Kohm @ 2watts.
I hope the attached circuit diagram of the line timebase helps fault finding in this area of the set.

DFWB.
Attached Thumbnails
Click image for larger version

Name:	AlbaT655LTB.jpg
Views:	39
Size:	83.4 KB
ID:	81640  
FERNSEH is online now   Reply With Quote
Old 6th Jul 2013, 11:49 am   #22
FERNSEH
Nonode
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 2,485
Default Re: Alba t655

From Jonz Valvepage website: A picture of the Alba T655.

DFWB.
Attached Thumbnails
Click image for larger version

Name:	t655.jpg
Views:	30
Size:	85.3 KB
ID:	81641  
FERNSEH is online now   Reply With Quote
Old 6th Jul 2013, 6:56 pm   #23
Focus Diode
Heptode
 
Focus Diode's Avatar
 
Join Date: Jan 2006
Location: Borough of Gateshead, UK
Posts: 877
Default Re: Alba t655

Top advice from David above. Encouraging to hear the Lopt doesn't heat up. The screen grid feed resistor is worth highlighting as if only 2W it'll be prone to changing value. A wirewound type of at least 5W should be fitted here.

Cheers,
Brian
Focus Diode is online now   Reply With Quote
Old 7th Jul 2013, 12:18 pm   #24
Freya
Heptode
 
Freya's Avatar
 
Join Date: Jan 2009
Location: Falmouth, Cornwall.
Posts: 573
Default Re: Alba t655

Those capacitors sound like early RS ones, all the ones i have come across have been ok but there is always a first time.
What is happening to the HT and EHT, can you monitor.

Stephen
Freya is offline   Reply With Quote
Old 7th Jul 2013, 6:29 pm   #25
beltinge bore
Pentode
 
Join Date: Dec 2012
Location: Herne Bay, Kent.
Posts: 113
Default Re: Alba t655

Today I have learned 2 things - Firstly if you fit a 470K resistor instead of a 47K resistor it don't half b******* up your line sync. and secondly don't ask SWMBO to hold a small component when somebody called Andy is playing ping pong! - I wouldn't mind but I let her watch it in glorious colour on a SONY 1320UB - But she did work out how to upload the picture because I am a Luddite when it comes to computers.

Tried NOS PL81 to no avail. Have changed R60 and R61 as values had drifted. R64 1.5K tests spot on after 25 mins running. C53 C55 & C54 are the only 3 caps I have not changed (I do not have any in stock).

HT stays steady but I do not trust myself to measure the EHT. The blue & white caps are Dubilier manufacture.

More pictures to follow - fingers crossed.

Many Thanks

Regards

Steve
Attached Thumbnails
Click image for larger version

Name:	015.jpg
Views:	64
Size:	53.7 KB
ID:	81705   Click image for larger version

Name:	006.jpg
Views:	78
Size:	69.1 KB
ID:	81706  

Last edited by beltinge bore; 7th Jul 2013 at 6:56 pm.
beltinge bore is offline   Reply With Quote
Old 7th Jul 2013, 7:20 pm   #26
Tazman1966
Octode
 
Tazman1966's Avatar
 
Join Date: May 2006
Location: St Albans, Herts (AL1)
Posts: 1,804
Default Re: Alba t655

To be honest, although reasonable in their day, many years of disuse and dampness will have affected those Dubilier caps and they are probably showing a fair old leak. I'd change them if I were you.
__________________
All the very best,
Tas
Tazman1966 is offline   Reply With Quote
Old 8th Jul 2013, 9:52 pm   #27
Zelandeth
Heptode
 
Zelandeth's Avatar
 
Join Date: Jun 2006
Location: Milton Keynes
Posts: 742
Default Re: Alba t655

Thus far I've found those Dublier caps to be 50/50 when I've encountered them. Not as bad as normal waxies, but I change them on sight generally unless they're buried somewhere *really* difficult to get to, or are in a very non-critical location in the circuit.
Zelandeth is offline   Reply With Quote
Old 11th Jul 2013, 7:56 pm   #28
beltinge bore
Pentode
 
Join Date: Dec 2012
Location: Herne Bay, Kent.
Posts: 113
Default Re: Alba t655

Hello Replaced the 2 dubilier caps.Sound is great picture is good for 20-25 minutes(cogging much improved) then sides of raster go wavy height goes up width comes in although its better than it was.I am resigned to the fact that the LOPT is duff.But as SHMBO said it wasn,t working at all when I started and an episode or Ready Steady Go lasts for 25minutes so I,ll just have to stick to that for now.

Thanks for all the help and advice.Regards Steve.
beltinge bore is offline   Reply With Quote
Old 12th Jul 2013, 7:20 am   #29
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 4,548
Default Re: Alba t655

You may well find that the LOPT improves after a while of intermittent use. J.
Heatercathodeshort is offline   Reply With Quote
Old 12th Jul 2013, 8:58 am   #30
Freya
Heptode
 
Freya's Avatar
 
Join Date: Jan 2009
Location: Falmouth, Cornwall.
Posts: 573
Default Re: Alba t655

Your next set is on auction site; search vintage Alba
I roll around laughing especially with the sellers id. A bit far gone maybe

Stephen

Looks like its a T301 1953 ish

Last edited by Freya; 12th Jul 2013 at 9:02 am. Reason: info added
Freya is offline   Reply With Quote
Old 12th Jul 2013, 9:08 am   #31
beltinge bore
Pentode
 
Join Date: Dec 2012
Location: Herne Bay, Kent.
Posts: 113
Default Re: Alba t655

I saw it Stephen on a par with the 250 Defiant & the Ekco with blown tube in St Albans!.SHMBO has bought me an early birthday present a Sobell T347 so i,ll probably be looking for more help quite soon!Regards Steve.
beltinge bore is offline   Reply With Quote
Old 12th Jul 2013, 9:13 am   #32
Freya
Heptode
 
Freya's Avatar
 
Join Date: Jan 2009
Location: Falmouth, Cornwall.
Posts: 573
Default Re: Alba t655

very nice, was that the one in Chelmsford ? if so it looks great.
Freya is offline   Reply With Quote
Old 12th Jul 2013, 6:47 pm   #33
beltinge bore
Pentode
 
Join Date: Dec 2012
Location: Herne Bay, Kent.
Posts: 113
Default Re: Alba t655

That,s the one my very own Essex girl (hope these words don,t come back to haunt me).I really wanted a T346 but this is pretty close.This was the first telly I ever took the back off.I was about 7 at the time (no screws holding the back on just "turn hooks").Regards Steve.
beltinge bore is offline   Reply With Quote
Old 14th Jul 2013, 8:16 pm   #34
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 4,548
Default Re: Alba t655

The Sobell 14" T347 must be well up in the 'most reliable 405 TV' league. These are truly superb receivers shunned by the Bakelite brigade. Good luck with it. John.
Heatercathodeshort is offline   Reply With Quote
Old 15th Jul 2013, 11:40 am   #35
FERNSEH
Nonode
 
FERNSEH's Avatar
 
Join Date: Mar 2005
Location: Gateshead, Tyne and Wear, UK.
Posts: 2,485
Default Re: Alba t655

And here is a picture of the Sobell T347.
As John states one of the most reliable 405 line set ever made. I remember these sets surviving well into the late sixties. Some sets had nothing whatsoever done to them. Others might have the odd valve replaced, that's all.
i'm looking forward to seeing this one on the the Forum.

DFWB.
Attached Thumbnails
Click image for larger version

Name:	SobellT347.jpg
Views:	29
Size:	33.8 KB
ID:	81969  
FERNSEH is online now   Reply With Quote
Old 15th Jul 2013, 1:15 pm   #36
beltinge bore
Pentode
 
Join Date: Dec 2012
Location: Herne Bay, Kent.
Posts: 113
Default Re: Alba t655

On family duties at the moment.SHMBO bought me a new toy a Yamaha 1970 YAS1 125 twin 2 stroke motorcycle to try to regain my lost youth on.(Dodgy Knee,end of life crisis or what)Raring to have a go at the little Sobell.My old mum borrowed the 60 from her father to buy a T346 1n 1955 when ITV started

.I remember the 3 element Aerial going up.(living in the shadow of Ally Pally the signal strength from Croydon on Band 111 was disappointing )I helped my my dad fit a new volume pot and it had an EY51.That was it.It a was replaced with the Pilot badged version of the Ultra 1770.Loads of frame faults and soft Mazda tube.

You chaps have turned me into a telly addict ! Thanks & Kind Regards Steve.
beltinge bore is offline   Reply With Quote
Old 15th Jul 2013, 2:06 pm   #37
beltinge bore
Pentode
 
Join Date: Dec 2012
Location: Herne Bay, Kent.
Posts: 113
Default Re: Alba t655

Can anybody tell me which Practical Television issues feature the Les Laurie Johns article on the Sobell TS17-T346 series please? Thanks & Regards Steve.
beltinge bore is offline   Reply With Quote
Old 15th Jul 2013, 8:06 pm   #38
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 4,548
Default Re: Alba t655

August and September 1957 Steve. J.
PS Covers scanned to help identify. Great to know LLJ's articles are still being read.
Attached Thumbnails
Click image for larger version

Name:	scan0001.jpg
Views:	28
Size:	144.8 KB
ID:	81977  

Last edited by Heatercathodeshort; 15th Jul 2013 at 8:12 pm. Reason: Scans added.
Heatercathodeshort is offline   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 4:38 pm.


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


Powered by vBulletin®
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright ©2002 - 2014, S&P Technology.