Granada Television Brochure, 1970s
Long Gone UK TV Shops
Memories of a Derwent Field Service Engineer
PYE Australia Circa 1971
Radios-TV VRAT
Fabulous Fablon
Thorn TX10 Chassis
Crusty-TV Museum, Analogue TV Network
Philips N1500 Warning!
Rumbelows
Thorn EMI Advertising
Thorn’s Guide to Servicing a VCR
Ferguson 3V24 De-Robed
Want to tell us a story?
Video Circuits V15 – Tripler Tester
Thorn Chassis Guide
Remove Teletext Lines & VCR Problems
Ceefax (Teletext)
Suggestions
Website Refresh
Colour TV Brochures
1970s Lounge Recreation
CrustyTV Vintage Television Museum
Linda Lovelace Experience
Humbars on a Sony KV2702
1972 Ultra 6713
D|E|R Service “The Best”
The one that got away
Technical information
The Line Output Stage
The map
Tales of a newly qualified young engineer.
Tales of a Radio Rentals Van Boy
Sanyo SMD
Disastrous Company Rebranding
1969 Philips G22K511
Memories Of The TV Trade
Crazy house
Dirty TV screens
Dual Standard and Single Standard CTV’s
Radios-TV on YouTube
The Winter of 62/63
A domestic audio installation
1979 Ferguson Videostar Deluxe 3V16
Music centre modifications
Unusual record player modification
B&K 467 Adapters
Mishaps In The Trade
1971 Beovision 3200
1971 Bush CTV1120
Granada Television Brochure, 1970s
Long Gone UK TV Shops
Memories of a Derwent Field Service Engineer
PYE Australia Circa 1971
Radios-TV VRAT
Fabulous Fablon
Thorn TX10 Chassis
Crusty-TV Museum, Analogue TV Network
Philips N1500 Warning!
Rumbelows
Thorn EMI Advertising
Thorn’s Guide to Servicing a VCR
Ferguson 3V24 De-Robed
Want to tell us a story?
Video Circuits V15 – Tripler Tester
Thorn Chassis Guide
Remove Teletext Lines & VCR Problems
Ceefax (Teletext)
Suggestions
Website Refresh
Colour TV Brochures
1970s Lounge Recreation
CrustyTV Vintage Television Museum
Linda Lovelace Experience
Humbars on a Sony KV2702
1972 Ultra 6713
D|E|R Service “The Best”
The one that got away
Technical information
The Line Output Stage
The map
Tales of a newly qualified young engineer.
Tales of a Radio Rentals Van Boy
Sanyo SMD
Disastrous Company Rebranding
1969 Philips G22K511
Memories Of The TV Trade
Crazy house
Dirty TV screens
Dual Standard and Single Standard CTV’s
Radios-TV on YouTube
The Winter of 62/63
A domestic audio installation
1979 Ferguson Videostar Deluxe 3V16
Music centre modifications
Unusual record player modification
B&K 467 Adapters
Mishaps In The Trade
1971 Beovision 3200
1971 Bush CTV1120
El-Cheapo Mains Isolating Transformer--Better than nothing!
Reading a few threads recently indicated the risks of our hobby--especially with some of the more oddball late 40's Philips sets currently under renovation, that have an odd heater and focus arrangement, whereby the chassis --isnt quite 'neutral'
Worth making up a Mains-Isolating transformer--el-cheapo style like I did recently to enable me to connect my 625 line Bush TV62 via its HDMI conversion to a freeview box and DVD player......
I had lying round, two toroidal transformers that had two secondaries of 55V each. One was 600VA, the other 500VA.
These I connected back-to-back as it were, Mains to the 600VA's primary and the secondaries of this first transformer connected to the secondaries of the 500VA second transformer.
'Isolated' supply is taken from the second transformer primary. Even though the transformers are rated at 600VA and 500VA, I would de-rate this to 400VA for safety reasons--just in case-- so for all the usual sets we would deal with this would be fine.....
Ive run the TV62 for several hours,--Its 140W consumption hardly making either transformer warm, and the supply the set 'sees' is 242V constant.
That sounds fine
Just a word of caution for anyone considering wiring two "110V site" transformers back to back, these are centre tapped 55V-0v-55V, 0V to Earth.
You need to be careful trying to wire these back to back and I would recommend missing both CT earth connections off the secondary's of both transformers by using a two wire connection.
This is for two reasons, 1) to isolate the earth completely, and 2) if both transformers are not exactly phased the same (secondary windings) it is possible to burn out or at least damage the transformers.
Ah--Now that's interesting, I hadn't considered the use of 'site-transformers' and I had no idea they were centre-tapped and more importantly earthed either!
--I wondered why the PAT Tester in work never liked 'em!
With my toroids, I bought them some years ago at Maplin, and both are the same make (Antrim) with the same secondary colour-codes, I just colour-matched each secondary connection, seems to work out OK, but did wonder whether to earth one side of each secondary or not--I didn't bother in the end....
I'm guessing that if for some reason you used a couple of transformers--and got the secondary phasing wrong, using the correct rated mains-fuse for the mains-side transformer,--this should blow....
--Just a thought.....
I'm guessing that if for some reason you used a couple of transformers--and got the secondary phasing wrong, using the correct rated mains-fuse for the mains-side transformer,--this should blow....
--Just a thought.....
It would more than likely trip the thermal cut-out first, although it would likely also overheat the windings and the inter-connection, lower voltage= higher current on that type of transformer.
Besides you want a fully floating supply for isolation purposes.
I pull a similar trick for small valve projects, only I use 6v transformers , so I can tap the heaters off the "middle" voltage.
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