625 To 405 Converters - UK Vintage Radio Repair and Restoration Discussion Forum

Glowing Bits! · 14th May 2013, 4:06 pm

I've been browsing the net recently and have found a 405 set nice & cheap and not too far away.

I also found a useful device (possibly useful) which would normally be fitted in Bush sets to convert them from 405 to 625/dual standard, will one of these onboard devices work with sets other than Bush, or do I run the risk of killing something?

Second question, will the dual standard sets still need a VHF signal/channel 1, 4 etc?

The plan was to convert the set to 625, then hopefully, a bog standard shop-bought channel 21 upwards modulator would be used, something in my head says this will still not work.

Should I still consider getting a proper (albeit expensive) 405 converter/modulator unit?

Please be aware that you're dealing with someone who has never been around 405/valve TV's, only modern transistor versions, I have been inside the more modern types but this is only to clean out the dust, that red wire has 'evil' written all over it!

Sean Williams · 14th May 2013, 6:29 pm

Er, ok, lets get some terminology sorted first.

There are line standards converters - Things like the Aurora, Pineapple, Dinosaur, and other home made designs - these convert 625 to 405 lines.

I think what you have found is more likely to be a band 3 converter, which would give a band 1 set the ability to receive BBC2 and the other channels that appeared. It could also be something that used to be called a "converter box", this was used in areas that had VHF cable television - it allowed UHF tuner based sets to be used on this system.

To get your 405 line set working you will need a standards converter, with a modulator - the Aurora is the only commercially available unit at present, and is all you will ever need.

HTH
Sean

raditechman · 14th May 2013, 7:15 pm

As we do not know what make/model the 405 line set is it is only possible to try and explain what happened in the days of changeover to 625.
Some sets could be converted from 405 lines to 625 lines, manufacturers sold kits to do this, Bush being one of them. These kits had a UHF tuner, an IF panel and some time base components, also a means of switching. The dropper resistor also had to be changed or have a section bridged as there were more valves in the heater chain. The results were not too good as the UHF tuners using valves did not have much gain.
There was also another unit which was I think for Murphy sets, where a 625 line tuner/IF's came in a wooden case which fitted under the TV, so the television sat on the unit. Once again it was made for that set and the set had provision to plug the unit in. Line time base switching already provided for in the set,
I doubt very much if it would be practical to convert your 405 line TV to 625 line.
If your set has a tuner with ITV marked it already can receive Band 3. 405 was on Band 1 and Band 3. 625 on Bands 4 & 5.
If you say you have only had experience on modern transistor sets I assume you mean LCD display televisions. If you buy an old valve 405 line television it will probably will have the metal chassis connected to one side of the mains, be careful CONNECT IT WRONG AND IT IS LIVE. There are also HIGH VOLTAGES in some areas of the set. It would not be advisable to power the set without making several checks first.
If you do get a 405 line television I suggest you ask on this forum for advice before you apply power, and I am sure there are many here who will advise you step by step. So that neither you, or the television, have an accident.
If later the television looks to be a good worker then you could buy a converter to supply a 405 line signal on VHF. The Aurora converter will do the job nicely. You will then be able to watch current TV transmissions on your old 405 line set.
John

Glowing Bits! · 14th May 2013, 7:37 pm

The set my eye is on is a Ferguson 978T, it only has one BBC channel.

I should have been clearer on the 'modern sets' bit, I'm referring to post-90's CRT's, flat panel sets are too fiddly to fix, sadly.

hamid_1 · 14th May 2013, 11:24 pm

Quote:

Originally Posted by Glowing Bits!

I also found a useful device (possibly useful) which would normally be fitted in Bush sets to convert them from 405 to 625/dual standard, will one of these onboard devices work with sets other than Bush, or do I run the risk of killing something?

In the early 1960s when 625 was about to start, some TV manufacturers offered "625 ready" TVs which could be upgraded later. They supplied a conversion kit which included a UHF tuner and the missing 625 bits (sometimes a whole new circuit board). The kit could only be used to convert the model or chassis that it was designed for. The conversion kit won't work with any old 405 line TV, only one specific set. If you are lucky enough to have the kit and the set it was made for, then you can convert it.

Quote:

Originally Posted by Glowing Bits!

Second question, will the dual standard sets still need a VHF signal/channel 1, 4 etc?

No, you can use a dual-standard TV on 625 only, without any 405/VHF signal. Just connect your 625 signal to the UHF aerial socket, switch the set to 625/UHF and tune in. This of course assumes your TV is in working order.

Quote:

Originally Posted by Glowing Bits!

The plan was to convert the set to 625, then hopefully, a bog standard shop-bought channel 21 upwards modulator would be used, something in my head says this will still not work.

This will work, again assuming you have a working 625 capable TV. Remember that dual standard TV sets are approaching 50 years old now, and will need some restoration before being put back into service. Only a small number of 405 TVs could be converted to dual standard. For the rest, you'll need a standards converter.

Quote:

Originally Posted by Glowing Bits!

Should I still consider getting a proper (albeit expensive) 405 converter/modulator unit?

It depends on how interested you are in seeing 405 line TV pictures. A proper standards converter (Aurora) is by far the easiest method of getting pictures on a 405 line TV. It will work with any model of 405 set, you won't be limited to dual-standard or convertible sets. If you're serious about getting a 405 line TV working, definitely get a converter.

raditechman · 15th May 2013, 7:38 am

Quote:

The set my eye is on is a Ferguson 978T, it only has one BBC channel

This set is for 405 only. Restore it then use an Aurora.
On this forum there is another member who has restored one of these sets and you can read about it.
https://www.vintage-radio.net/forum/...ad.php?t=52632

radiotircoed · 15th May 2013, 8:57 am

The Aurora is truly a fantastic device and as far as I'm concerned its the only way to go...

Amraduk · 15th May 2013, 10:11 am

Hello Sean,

Quote:

Originally Posted by Sean Williams

I think what you have found is more likely to be a band 3 converter, which would give a band 1 set the ability to receive BBC2 and the other channels that appeared.

Band 3 converters were used to enable reception of ITV 405-line transmissions in Band 3 on a Band-1 only 405-line TV. There was no BBC 2 television in 405-line only days - they were prior to 1964 when BBC 2 was launched on 625-lines only in the UHF bands 5 and 6!

Regards,

Dave. G8TVW.

Nicklyons2 · 15th May 2013, 10:38 am

Quote:

Originally Posted by Amraduk

Hello Sean,

Band 3 converters were used to enable reception of ITV 405-line transmissions in Band 3 on a Band-1 only 405-line TV. There was no BBC 2 television in 405-line only days - they were prior to 1964 when BBC 2 was launched on 625-lines only in the UHF bands 5 and 6!

Regards,

Dave. G8TVW.

Bands 4 & 5 channels 21 - 34 & 39 - 68

Boom · 15th May 2013, 11:00 am

Is there some confusion here? There were two types of band III convertors that I knew of (maybe more). One type enabled a single channel 405 line set to receive band III signals and the other convertor enabled 625 line UHF only sets to receive the band III signals from VHF communal aerial systems.

Nicklyons2 · 15th May 2013, 11:23 am

Dave the item you mean was an 'up-convertor' and as you say were used in systems where the UHF 'off-air' had been previously down converted to get it around (usually an ancient) communal system, AND also when using a UK TV in the Irish Republic where RTE and the cable system in Dublin used VHF.

Boom · 15th May 2013, 11:38 am

Quote:

Originally Posted by Nicklyons2

also when using a UK TV in the Irish Republic where RTE and the cable system in Dublin used VHF.

Australia as well I believe. I know I got asked for a couple of convertors when a friend emigrated there so he could take his TV's with him.

audiomagpie · 15th May 2013, 7:57 pm

Quote:

Originally Posted by raditechmanOn this forum there is another member who has restored one of these sets and you can read about it.
[url

https://www.vintage-radio.net/forum/showthread.php?t=52632[/url]

Wow! Doesn't time fly, that was my first attempt at TV, I've just counted 13 sets in the workshop now!

The little Fergy would be an excellent choice, it was very kind to me, very easy one piece chassis to work on. I also stripped a scrap chassis, so would have spares should you need anything, although a good selection of capacitors is the main thing you'll need!

Greg

Freya · 17th May 2013, 7:56 am

I also saw this conversion kit, details can be found using a browser searching "Vintage Bush TV converter for 405 to 626 lines".
It looked to be designed for two specific bush sets ?.

Steve

Heatercathodeshort · 19th May 2013, 12:30 pm

The 978T is a TRF model fix tuned to Sutton Coldfield channel 4. You will require a modulator/converter that will tune to this frequency. The AURORA is excellent.
It might sound expensive but it's just over 2 fill ups of diesel in my Ford Ranger or 27 packs of fags if you smoke. [I don't] To be honest, I don't know how it can be made for the price.
If you only have a couple of 405 receivers it may be difficult to justify, especially in the financial situation today but you really can't get the full enjoyment of restoring old telly receivers without one. You cannot 'convert' a receiver of this type to operate on any modern device such as DVD players or set top boxes. Hope you get it working. As Greg has mentioned, it is an ideal receiver for your first project as are any Ferguson models. John.

1955APREN · 8th Aug 2013, 11:43 pm

Quote:

Originally Posted by Nicklyons2

Dave the item you mean was an 'up-convertor' and as you say were used in systems where the UHF 'off-air' had been previously down converted to get it around (usually an ancient) communal system, AND also when using a UK TV in the Irish Republic where RTE and the cable system in Dublin used VHF.

What about the communal system used in Newtown mid Wales this was a field engineer's nightmare . Dreaded thoughts from the past.

Nicklyons2 · 10th Aug 2013, 12:58 pm

I didn't know of the Newtown system, tell us more! Did it transpose BBC1 and ITV 625 to VHF as well as BBC2 whilst still carrying the 405 service? Did it ever work very successfully in colour? Did it ever get as far as Ch4?

I don't know why but VHF carrier communal systems never seemed to work particularly well or successfully in the UK, perhaps we never had enough of them to get familiar with them and sort the foibles, but in Dublin and many cities on the Continent these systems worked very well on city-wide scales often carrying, what was in the 1970s era, an astonishing 8 or 10 channels. Strange in the UK we seemed to struggle to get 4 channels down ours.

winston_1 · 17th Aug 2013, 1:31 am

Stevenage had a similar system. It lasted into the analogue satellite era and I seem to recall it carried Eurosport and another satellite channel in addition to the main channels all at VHF. My sister used a dual standard TV on it arranged to use 625 at VHF. When it died I sent her all the local shops to ask for a TV with a VHF tuner. No one could supply one. So I phoned Philips technical who said they knew about Stevenage but were not prepared to market a set with a VHF tuner for such a small market and told me to use an upconverter. I considered getting a European grey import in Tottenham Court Rd London and changing the sound filters but in the end didn't bother as I found a second hand upconverter in the local paper small ads.

Restoration73 · 18th Aug 2013, 1:17 pm

Frequency up converters were widely available for VHF in, UHF out. One
example is the Labgear CM6022RA. I used one to help a customer who had
imported a U.S. game console with a Ch. A4 output to UHF. The tv locked
to the line frequency, slight tweak to the field hold, no colour (3.58) and no
sound of course.
These were used by TV dxers too. There was also another make of these.

14th May 2013, 4:06 pm	#1
Glowing Bits! Octode Join Date: Oct 2011 Location: Wrexham, North Wales, UK. Posts: 1,457	625 To 405 Converters I've been browsing the net recently and have found a 405 set nice & cheap and not too far away. I also found a useful device (possibly useful) which would normally be fitted in Bush sets to convert them from 405 to 625/dual standard, will one of these onboard devices work with sets other than Bush, or do I run the risk of killing something? Second question, will the dual standard sets still need a VHF signal/channel 1, 4 etc? The plan was to convert the set to 625, then hopefully, a bog standard shop-bought channel 21 upwards modulator would be used, something in my head says this will still not work. Should I still consider getting a proper (albeit expensive) 405 converter/modulator unit? Please be aware that you're dealing with someone who has never been around 405/valve TV's, only modern transistor versions, I have been inside the more modern types but this is only to clean out the dust, that red wire has 'evil' written all over it! Last edited by Glowing Bits!; 14th May 2013 at 4:23 pm.

14th May 2013, 6:29 pm	#2
Sean Williams Dekatron Join Date: Feb 2005 Location: St.Ippolyts, Hitchin, Hertfordshire QRA IO91UW Posts: 3,517	Re: 625 To 405 Converters Er, ok, lets get some terminology sorted first. There are line standards converters - Things like the Aurora, Pineapple, Dinosaur, and other home made designs - these convert 625 to 405 lines. I think what you have found is more likely to be a band 3 converter, which would give a band 1 set the ability to receive BBC2 and the other channels that appeared. It could also be something that used to be called a "converter box", this was used in areas that had VHF cable television - it allowed UHF tuner based sets to be used on this system. To get your 405 line set working you will need a standards converter, with a modulator - the Aurora is the only commercially available unit at present, and is all you will ever need. HTH Sean __________________ Engineers make things work and have spare bits when finished

14th May 2013, 7:15 pm	#3
raditechman Heptode Join Date: Feb 2007 Location: West London, UK. Posts: 867	Re: 625 To 405 Converters As we do not know what make/model the 405 line set is it is only possible to try and explain what happened in the days of changeover to 625. Some sets could be converted from 405 lines to 625 lines, manufacturers sold kits to do this, Bush being one of them. These kits had a UHF tuner, an IF panel and some time base components, also a means of switching. The dropper resistor also had to be changed or have a section bridged as there were more valves in the heater chain. The results were not too good as the UHF tuners using valves did not have much gain. There was also another unit which was I think for Murphy sets, where a 625 line tuner/IF's came in a wooden case which fitted under the TV, so the television sat on the unit. Once again it was made for that set and the set had provision to plug the unit in. Line time base switching already provided for in the set, I doubt very much if it would be practical to convert your 405 line TV to 625 line. If your set has a tuner with ITV marked it already can receive Band 3. 405 was on Band 1 and Band 3. 625 on Bands 4 & 5. If you say you have only had experience on modern transistor sets I assume you mean LCD display televisions. If you buy an old valve 405 line television it will probably will have the metal chassis connected to one side of the mains, be careful CONNECT IT WRONG AND IT IS LIVE. There are also HIGH VOLTAGES in some areas of the set. It would not be advisable to power the set without making several checks first. If you do get a 405 line television I suggest you ask on this forum for advice before you apply power, and I am sure there are many here who will advise you step by step. So that neither you, or the television, have an accident. If later the television looks to be a good worker then you could buy a converter to supply a 405 line signal on VHF. The Aurora converter will do the job nicely. You will then be able to watch current TV transmissions on your old 405 line set. John

14th May 2013, 7:37 pm	#4
Glowing Bits! Octode Join Date: Oct 2011 Location: Wrexham, North Wales, UK. Posts: 1,457	Re: 625 To 405 Converters The set my eye is on is a Ferguson 978T, it only has one BBC channel. I should have been clearer on the 'modern sets' bit, I'm referring to post-90's CRT's, flat panel sets are too fiddly to fix, sadly.

15th May 2013, 8:57 am	#7
radiotircoed Pentode Join Date: Nov 2005 Location: Tircoed Forest Village - Swansea, UK. Posts: 193	Re: 625 To 405 Converters The Aurora is truly a fantastic device and as far as I'm concerned its the only way to go... __________________ Radio Tircoed - Working for the Community

15th May 2013, 11:00 am	#10
Boom Retired Dormant Member Join Date: Jan 2007 Location: Westbury, Wiltshire, UK. Posts: 2,451	Re: 625 To 405 Converters Is there some confusion here? There were two types of band III convertors that I knew of (maybe more). One type enabled a single channel 405 line set to receive band III signals and the other convertor enabled 625 line UHF only sets to receive the band III signals from VHF communal aerial systems.

15th May 2013, 11:23 am	#11
Nicklyons2 Octode Join Date: Jan 2013 Location: Barnsley, South Yorkshire, UK. Posts: 1,517	Re: 625 To 405 Converters Dave the item you mean was an 'up-convertor' and as you say were used in systems where the UHF 'off-air' had been previously down converted to get it around (usually an ancient) communal system, AND also when using a UK TV in the Irish Republic where RTE and the cable system in Dublin used VHF.

17th May 2013, 7:56 am	#14
Freya Octode Join Date: Jan 2009 Location: Falmouth, Cornwall, UK. Posts: 1,989	Re: 625 To 405 Converters I also saw this conversion kit, details can be found using a browser searching "Vintage Bush TV converter for 405 to 626 lines". It looked to be designed for two specific bush sets ?. Steve

19th May 2013, 12:30 pm	#15
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: 625 To 405 Converters The 978T is a TRF model fix tuned to Sutton Coldfield channel 4. You will require a modulator/converter that will tune to this frequency. The AURORA is excellent. It might sound expensive but it's just over 2 fill ups of diesel in my Ford Ranger or 27 packs of fags if you smoke. [I don't] To be honest, I don't know how it can be made for the price. If you only have a couple of 405 receivers it may be difficult to justify, especially in the financial situation today but you really can't get the full enjoyment of restoring old telly receivers without one. You cannot 'convert' a receiver of this type to operate on any modern device such as DVD players or set top boxes. Hope you get it working. As Greg has mentioned, it is an ideal receiver for your first project as are any Ferguson models. John.

10th Aug 2013, 12:58 pm	#17
Nicklyons2 Octode Join Date: Jan 2013 Location: Barnsley, South Yorkshire, UK. Posts: 1,517	Re: 625 To 405 Converters I didn't know of the Newtown system, tell us more! Did it transpose BBC1 and ITV 625 to VHF as well as BBC2 whilst still carrying the 405 service? Did it ever work very successfully in colour? Did it ever get as far as Ch4? I don't know why but VHF carrier communal systems never seemed to work particularly well or successfully in the UK, perhaps we never had enough of them to get familiar with them and sort the foibles, but in Dublin and many cities on the Continent these systems worked very well on city-wide scales often carrying, what was in the 1970s era, an astonishing 8 or 10 channels. Strange in the UK we seemed to struggle to get 4 channels down ours.

17th Aug 2013, 1:31 am	#18
winston_1 Hexode Join Date: Oct 2012 Location: London, UK. Posts: 498	Re: 625 To 405 Converters Stevenage had a similar system. It lasted into the analogue satellite era and I seem to recall it carried Eurosport and another satellite channel in addition to the main channels all at VHF. My sister used a dual standard TV on it arranged to use 625 at VHF. When it died I sent her all the local shops to ask for a TV with a VHF tuner. No one could supply one. So I phoned Philips technical who said they knew about Stevenage but were not prepared to market a set with a VHF tuner for such a small market and told me to use an upconverter. I considered getting a European grey import in Tottenham Court Rd London and changing the sound filters but in the end didn't bother as I found a second hand upconverter in the local paper small ads.

18th Aug 2013, 1:17 pm	#19
Restoration73 Nonode Join Date: Jun 2013 Location: Surbiton, SW London, UK. Posts: 2,801	Re: 625 To 405 Converters Frequency up converters were widely available for VHF in, UHF out. One example is the Labgear CM6022RA. I used one to help a customer who had imported a U.S. game console with a Ch. A4 output to UHF. The tv locked to the line frequency, slight tweak to the field hold, no colour (3.58) and no sound of course. These were used by TV dxers too. There was also another make of these.