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 24th Apr 2005, 5:37 pm   #1
huminahuminaint
Retired Dormant Member
 
Join Date: Apr 2005
Location: Pittsburgh, PA
Posts: 7
Default Decca Bradford chassis, help wanted to use in USA

We have a Keracolor TV and when we plug it in we get sound (static) and no picture. When we had a repair man come over he said that the no picture was the result of bad vacuums tubes so so far we replaced the PY500 but not yet the other one (Pl509 I think we have coming in). I thought that after you replace one of the tubes there should be some display on the screen but the screen displays nothing. I am very worried that the main picture tube is dead but am not positive. I thought a schematic might help us out. Are there any tests we could run or anything along those lines?

I should also mention that I had this TV shipped over from the UK (could this have happened in shipping?) and that I set it up with a 220 voltage adapter so that it would work. I think I remember reading that sometimes when you convert the voltage and not frequency on foreign tvs that they don't work, could this be my problem?


Lucian
Attached Thumbnails
Click image for larger version

Name:	IMG_0504.JPG
Views:	440
Size:	86.0 KB
ID:	530  
huminahuminaint is offline  
Old 24th Apr 2005, 7:21 pm   #2
Nickthedentist
Dekatron
 
Nickthedentist's Avatar
 
Join Date: Jan 2005
Location: Oxford, UK.
Posts: 17,846
Default Re: Decca Bradford chassis, help wanted

Quote:
Originally Posted by huminahuminaint
I should also mention that I had this TV shipped over from the UK (could this have happened in shipping?) and that I set it up with a 220 voltage adapter so that it would work. I think I remember reading that sometimes when you convert the voltage and not frequency on foreign tvs that they don't work, could this be my problem?


Lucian
Lucian,

The best way of powering it would be from an autotransformer (big and heavy but not too expensive) rather than one of those little, solid-state power convertors.

Don't forget nearly all European TVs of that period (and currently) will have PAL colour decoders and be designed for 625-line operation. In other words they won't receive American TV even if you do power it up properly (although you should see snow on the screen as well as hear white noise/mush from the speaker). To display a picture, your best bet would be to acquire a European video player (with the right type of RF output, suitable for feeding into the aerial socket) and some European tapes to go with it.

Good luck,
Nick.
Nickthedentist is online now  
Old 24th Apr 2005, 8:11 pm   #3
Hybrid tellies
Nonode
 
Hybrid tellies's Avatar
 
Join Date: Jan 2004
Location: 1966-1976 Coverack in Cornwall and Helston Cornwall. 1976-present Bristol/Bath area.
Posts: 2,965
Default Re: Decca Bradford chassis, help wanted

In addition to what has already been said don't forget in your country you use the VHF TV bands wheras this set will only have a UHF tuner. Looking at the photo I can positivley identify this set as the earliar (and first) 10 version. Mine has exactly the same chassis.
There are many different faults that could cause the symptoms sound no picture, the line output valves being only one of them. The line output stage is protected by a 500mA a/s fuse in the HT line and a 100mA fuse on the feed to the EHT tripler. Both of these should be checked. If these fuses are ok you should check the voltages around the line output valves checking the Screen grid of the line output valve for 250v or so and at least -70v on the control grid of the line output valve. If the HT fuse has blown check for low resistance between the top caps of the valves and chassis. You should see something over 2M ohmes any less could be the Line output transformer or a couple of high voltage caps.
I hope these are a few helpful pointers. As I am a big Decca Bradford fan if you pay my return fare plus spending money I will come and take a look at it for you
__________________
Simon
BVWS member
Hybrid tellies is offline  
Old 24th Apr 2005, 8:27 pm   #4
AC/HL
Dekatron
 
AC/HL's Avatar
 
Join Date: Nov 2003
Location: Heckmondwike, West Yorkshire, UK.
Posts: 9,642
Default Re: Decca Bradford chassis, help wanted

Hi Lucian,
It won't help with your repair, but you may be interested in the origin of the name of this chassis.
It was indeed designed in Bradford (West Yorkshire, Northern England) but not by Decca. It was to have been the next Baird chassis. The designer went to Decca and took his design with him, presumably either because he owned the design, or Baird sold it.
AC/HL is offline  
Old 25th Apr 2005, 12:44 am   #5
Hybrid tellies
Nonode
 
Hybrid tellies's Avatar
 
Join Date: Jan 2004
Location: 1966-1976 Coverack in Cornwall and Helston Cornwall. 1976-present Bristol/Bath area.
Posts: 2,965
Default Re: Decca Bradford chassis, help wanted

Has the set worked and broken down or was it faulty when you bought it?
Another point, and speaking from experience, 220v is on the lower limit of the mains input range. The manual specifies 220-250v and they are happier when the mains supply is nearer the upper limit. When this Telly was new back in 1971 the mains voltage here in the UK was rated at 240v!
__________________
Simon
BVWS member
Hybrid tellies is offline  
Old 25th Apr 2005, 10:41 pm   #6
huminahuminaint
Retired Dormant Member
 
Join Date: Apr 2005
Location: Pittsburgh, PA
Posts: 7
Default Re: Decca Bradford chassis, help wanted

Thank you all for your help on getting the TV to work. After I replaced the 2ed bulb everything powered up fine. I do have one more question (and I am sure I will sound stupid, im not very familiar with this TV model) but I am having trouble hooking it up to a DVD player, I bought a PAL/NTSC converter that converts the signal which should make it work with a DVD player I just dont know what settings to put the TV on. The buttons/knobs on the front panel are as follows: 1, 2, 1, 2, T, B, C, K and then the power/volume knob. I am not atall sure what the "1" and "2" buttons do and why there are two sets of them... any help would be greatly appreciated.
huminahuminaint is offline  
Old 25th Apr 2005, 11:23 pm   #7
Paul_RK
Dekatron
 
Paul_RK's Avatar
 
Join Date: Nov 2003
Location: Fakenham, Norfolk, UK.
Posts: 4,256
Default Re: Decca Bradford chassis, help wanted

Hi Lucian.

Your control panel sounds a little different to that on my Keracolor, which lacks the "T" control - is that a knob like the others (Brightness, Contrast, Colour and Volume) or a press button like those above? The "1,2,1,2" buttons are tunable to four UHF channels. When the sets were made there were only three domestic channels, BBC1, BBC2 and ITV. Any button could be set to any channel, so viewers would usually have set the top button to BBC1, the next to BBC2 and the third to ITV, leaving the fourth for the projected "ITV2" service which when it was eventually launched was called Channel 4.

If the "T" control is a fifth button it's probably provided for use with a video recorder. If you have a suitable UHF signal you should be able to tune any of the buttons to it: your set's tuner is probably different from mine so I can't say exactly how, but turning a button once it's depressed is a common method.

Paul
Paul_RK is online now  
Old 26th Apr 2005, 12:39 am   #8
huminahuminaint
Retired Dormant Member
 
Join Date: Apr 2005
Location: Pittsburgh, PA
Posts: 7
Default Re: Decca Bradford chassis, help wanted

The "t" button is a knob, not a button. I thought it was for tuning because it seems to tune the 1212 buttons. But when I try to tune one of the preset 1212 buttons to the pal hookup nothing comes through.

Thanks,
Lucian
huminahuminaint is offline  
Old 26th Apr 2005, 12:51 am   #9
Hybrid tellies
Nonode
 
Hybrid tellies's Avatar
 
Join Date: Jan 2004
Location: 1966-1976 Coverack in Cornwall and Helston Cornwall. 1976-present Bristol/Bath area.
Posts: 2,965
Default Re: Decca Bradford chassis, help wanted

I am glad you have got this set going. As I mentioned earliar this is the original Decca Bradford 10 which uses a mechanical tuner with four selectors but the fifth button is the tuning one.
It sounds like you need a UHF modulator. I use the VCR modulator to play DVD's through my Decca.
Finally if that PL509 fails again in the near future you may well have to find a way of upping that mains 220v to at least nearer the 230v mark.

Cheers
Simon
__________________
Simon
BVWS member

Last edited by Mike Phelan; 18th Jun 2007 at 1:29 pm. Reason: Tidy up for archiving
Hybrid tellies is offline  
Old 26th Apr 2005, 1:33 am   #10
huminahuminaint
Retired Dormant Member
 
Join Date: Apr 2005
Location: Pittsburgh, PA
Posts: 7
Default Re: Decca Bradford chassis, help wanted

I currently have a DVD player hooked up to a UHF modulator hooked up to a PAl converter hooked up to the TV. The problem I am having is getting the picture on the screen from the DVD player. Does this require tuning via the inside controls? I was hoping to be able to fix this set up by myself and gain experence with this model but is it recomended that I hire someone to come to the house?

Thanks,
Lucian
huminahuminaint is offline  
Old 26th Apr 2005, 4:34 am   #11
Paul_RK
Dekatron
 
Paul_RK's Avatar
 
Join Date: Nov 2003
Location: Fakenham, Norfolk, UK.
Posts: 4,256
Default Re: Decca Bradford chassis, help wanted

From Simon's description (I don't know this particular tuner) you should be able to tune in whichever of the upper four buttons is currently depressed using the T knob. It's pretty much unheard of for any TV to require an internal operation to tune it. The chief thing that occurs to me about the system you have to feed it is the matter of line standards: I don't think the PAL converter would change the US 525-line system to 625 lines. I'd guess the easiest and cheapest solution would be for you to import a multi-region (as regards discs) DVD player made for the UK market. All you would need to be sure of is that it offers an RF output - current video equipment isn't something I'm at all knowledgeable about, but I believe many, perhaps the great majority, of today's DVD players only have a SCART output facility.

Paul
Paul_RK is online now  
Old 30th Apr 2005, 5:55 pm   #12
turret_tuner
Retired Dormant Member
 
turret_tuner's Avatar
 
Join Date: Jul 2003
Location: S. W. Midlands, UK.
Posts: 36
Default Re: Decca Bradford chassis, help wanted

Hi huminahuminaint, in your last post you say DVD player hooked up to UHF modulator hooked up to PAL converter hooked up to TV. I presume you mean player to converter to modulator to TV as all the converters I have come across work on the video signal not on the uhf signal.

The tuning arrangement of your TV was unusual even in the UK. It was usual at that time to have the 4 push buttons each one being tunable across the UHF band. It takes many many turns of the button to tune across the whole band. Your tuner is unusual (although many Decca Bradford sets had this type) because there is the tuning knob which is mechanically engaged to whichever of the 4 buttons is depressed. You should see the button turning as you turn the tuning knob. Again many turns are required to get from one end of the band to the other. But be careful of turning too fast and going past the mechanical limit and breaking something. If your UHF modulator is working and hooked into the TV I would expect to see some change of brightness, noise or some difference on the screen as you tune through the modulator channel, even if there is no video input to the modulator.
turret_tuner is offline  
Old 30th Apr 2005, 11:37 pm   #13
Sideband
Dekatron
 
Sideband's Avatar
 
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,572
Default Re: Decca Bradford chassis, help wanted

Not wishing to put too much of a dampener on things.... DVD-PAL converter-UHF modulator sounds the correct order of things to me but the TV is designed for 625 lines and 50Hz field. The PAL converter is not likely to change the American 525 line and 60Hz field to 625 and 50Hz respectively. So even if a picture can be tuned in, it may be difficult, if not impossible, to obtain a stable locked picture. If the DVD player has a PAL output it will probably be 'Quasi-PAL' which is PAL at 525 lines 60Hz. I'm quite sure the TV will not like these signals and will not 'lock'.


Modern UK TV's are designed to operate from 'Quasi-PAL' so that we can enjoy American VHS tapes and DVD's but the poor old Decca was made long before this was necessary.

Rich.
Sideband is offline  
Old 10th May 2005, 10:41 pm   #14
Booby
Retired Dormant Member
 
Booby's Avatar
 
Join Date: Jan 2005
Posts: 18
Default Re: Decca Bradford chassis, help wanted

Not sure how it behaves with DVDs? but if its pre 1975 it needed a modification on the flywheel sync circuit to get a locked stable picture with VCRs. Usually just a change of a resitor and capacitor.
Booby is offline  
Old 6th Jun 2005, 9:12 pm   #15
huminahuminaint
Retired Dormant Member
 
Join Date: Apr 2005
Location: Pittsburgh, PA
Posts: 7
Default Re: Decca Bradford chassis, help wanted

Quote:
Originally Posted by Booby
Not sure how it behaves with DVDs? but if its pre 1975 it needed a modification on the flywheel sync circuit to get a locked stable picture with VCRs. Usually just a change of a resitor and capacitor.

I just got a new modulator in (the old one was only for channel 3/4, the new one allows for higher channels). My set-up is DVD Player- Pal Converter- UHF Modulator - TV. Currently I am able to tune in the DVD player signal but there is alot of static and no clear sound. What would I need to buy to have this thing working? I called a TV repair service and they said that they think the tuner is bad, is this a possibility? Or is there some sort of adjustment I have to make with the decca inside?


Thanks,
Lucian
huminahuminaint is offline  
Old 6th Jun 2005, 9:53 pm   #16
huminahuminaint
Retired Dormant Member
 
Join Date: Apr 2005
Location: Pittsburgh, PA
Posts: 7
Default Re: Decca Bradford chassis, help wanted

Wait, if I get a multi-region dvd player made for the UK would I still need a UHF modulator or would it be built to work already with the TV? If not do you think there might be any problems with having a UK tv go through a US UHF modulator to a UK tv?

Should buying the multi-region DVD player be my first step or is there something else I should do before I get this to make it work?
huminahuminaint is offline  
Old 6th Jun 2005, 10:05 pm   #17
Sideband
Dekatron
 
Sideband's Avatar
 
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,572
Default Re: Decca Bradford chassis, help wanted

Back to my comments about the different TV systems between UK and USA. One other difference is the intercarrier sound system. UK is 6Mhz, USA is, I think, 4.5 Mhz. The UHF modulator should have a 6Mhz sound carrier or it may have switches to suit different systems. Check the modulator first in case it has switchable sound. If not then changes will have to be made to the sound I.F of the TV. It will be easier if a modulator with 6Mhz sound is used. For info, UK has 6Mhz sound, Europe has 5.5Mhz sound and North and South America is (I think) 4.5Mhz with the possible exception of Brazil. If the wrong sound carrier is used, you will have severe buzzing/static.


Rich.
Sideband is offline  
Old 7th Jun 2005, 2:10 am   #18
huminahuminaint
Retired Dormant Member
 
Join Date: Apr 2005
Location: Pittsburgh, PA
Posts: 7
Default Re: Decca Bradford chassis, help wanted

The UHF modulator is a "cam-25 uhf" i tried looking on the exterior for mhz but it didnt say, should i open it up and see if the inside tells? What kind of changes to the "sound i.f."? by "you will have severe buzzing/static. " is that just regarding sound or picture too? It would be great if first Icould tackle the picture static issue and then the sound one, unless they are both interconnected. Thank you for all your help by the way, i dont know what i would do with out it.

How about these for DVD players:

http://cgi.ebay.co.uk/ws/eBayISAPI.d...778900129&rd=1

http://cgi.ebay.co.uk/ws/eBayISAPI.d...778911861&rd=1

http://cgi.ebay.co.uk/ws/eBayISAPI.d...779596655&rd=1


Also, after I buy one of those DVD players what other complications will there be or will I be basically set?

Last edited by huminahuminaint; 7th Jun 2005 at 2:22 am.
huminahuminaint is offline  
Old 7th Jun 2005, 10:01 pm   #19
Booby
Retired Dormant Member
 
Booby's Avatar
 
Join Date: Jan 2005
Posts: 18
Default Re: Decca Bradford chassis, help wanted

You should not have any problem with the DVDs you mention. They will be 220 volts of course but may have a voltage switcher?
The picture should be ok after installing one of these, as it is a lot more stable and clean than a VCR. When VCRs first came out, these sets use to roll a bit and needed the flywheel sync mod I mentioned earlier, only because of the roughness of the VCR signal.

With regards to your modulator.....

The other thing to mention about your modulator is that it may be "European" PAL which has a ' G ' suffix .The sound on this is at 5.5 mhz

To get sound out of the Bradford your modulator needs to be "British" PAL this has an ' I ' suffix the sound on this is 6 mz.

PAL ' I ' is also found in Hong Kong/S.Africa


hope that is of help?

Last edited by Booby; 7th Jun 2005 at 10:07 pm.
Booby is offline  
Old 19th Jun 2005, 7:30 pm   #20
Sideband
Dekatron
 
Sideband's Avatar
 
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,572
Default Re: Decca Bradford chassis, help wanted

Quote:
Originally Posted by huminahuminaint
I just read that:

"This converter only works with a 60Hz PAL TV"
regarding my current converter. This tv is 60Hz correct?
Hi Lucian.

The Decca set is 50Hz....all UK sets are. See my first posting in this thread. UK TV spec = 230V 50Hz mains. PAL I system.....6Mhz Intercarrier sound.


Rich.
Sideband is offline  
Closed Thread




All times are GMT +1. The time now is 11:58 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.