Sinclair FTV1/B - UK Vintage Radio Repair and Restoration Discussion Forum

Osiris69 · 28th Jan 2017, 3:59 am

Hi all,
Just found in charity shop for a pound.
Can anyone let me know the polarity of the power socket? Square flat battery with it showing zero volts, so need to make up a power adapter providing 6VDC.
Really interesting little set with one of a kind CRT, would love to see it work so connecting a 1980's Atari console with UHF/VHF output.
Have found a Sinclair Research Tech Manual (1986) free online, but I can't find detail on adapter socket polarity.

TonyDuell · 28th Jan 2017, 5:38 am

The circuit diagram in the manual is none-too-clear (and whoever drew the battery is an idiot!) but it appears that the centre pin on the power connector is -ve.

But you can check it quite easily without opening the case. The +ve side of the power connector goes to the power switch (ganged to the volume control) only, and to nowhere else. The -ve side goes to the ground line. The outer (sleeve) of the earphone socket goes to ground via a 47R resistor. So check between the sleeve of the earphone socket and each side of the power connector (set turned off, no battery), whichever one shows 47R resistance (the other will be infinite) is the -ve.

Boater Sam · 28th Jan 2017, 7:38 am

If you are making up a battery pack, why not put a diode in series inside to prevent any future destructive errors, you could allow for the volts drop in the pack make up.
Or even better a fat diode in reverse across the + & - inside with a fuse in the supply to blow if connected wrongly.

Courtney Louise · 28th Jan 2017, 9:25 am

How would you make a battery for one of these as I have a boxed one I would love to use on a battery.

Jac · 28th Jan 2017, 9:34 am

The middle pin is minus.
The outer rim is plus.

Jac

60 oldjohn · 28th Jan 2017, 10:05 am

Keep it in the Airing cupboard for a month before powering up, Guess how I know! not a Sinclair and it was only AA batteries. A sickening fizz and an Ozone smell, I had the set from new and thought I would try it out again.

John.

Cobaltblue · 28th Jan 2017, 11:05 am

ISTR the original batteries were made by Poloroid, they were the same type that were used in the film packs.

During the late 80's Greenweld in Southampton were selling these in pieces.

Good tip from John about drying them out I have a couple in stores bought from Boot sales 20 years ago,

Cheers

Mike T

Sideband · 28th Jan 2017, 2:26 pm

I have one of these in working order. The only way I can get pictures is to connect the aerial to the RF out of a VCR. I'm working on a low-power UHF modulator with a range of a few 10's of feet

electronicskip · 28th Jan 2017, 3:39 pm

Quote:

Originally Posted by Cobaltblue

ISTR the original batteries were made by Poloroid, they were the same type that were used in the film packs.

I have one of these little FTV1/B units and as Cobolt says the batteries were made by Polaroid.
When I was young I used to have a Polaroid instant Camera which after I'd used the film, I used to strip out the battery from the film cartridge and use it in the Sinclair! Early recycling!

Osiris69 · 29th Jan 2017, 2:16 am

Quote:

Originally Posted by Jac

The middle pin is minus.
The outer rim is plus.

Thank you.

28th Jan 2017, 3:59 am	#1
Osiris69 Tetrode Join Date: Mar 2010 Location: Newport Pagnell, Buckinghamshire, UK. Posts: 57	Sinclair FTV1/B Hi all, Just found in charity shop for a pound. Can anyone let me know the polarity of the power socket? Square flat battery with it showing zero volts, so need to make up a power adapter providing 6VDC. Really interesting little set with one of a kind CRT, would love to see it work so connecting a 1980's Atari console with UHF/VHF output. Have found a Sinclair Research Tech Manual (1986) free online, but I can't find detail on adapter socket polarity.

28th Jan 2017, 5:38 am	#2
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Sinclair FTV1/B The circuit diagram in the manual is none-too-clear (and whoever drew the battery is an idiot!) but it appears that the centre pin on the power connector is -ve. But you can check it quite easily without opening the case. The +ve side of the power connector goes to the power switch (ganged to the volume control) only, and to nowhere else. The -ve side goes to the ground line. The outer (sleeve) of the earphone socket goes to ground via a 47R resistor. So check between the sleeve of the earphone socket and each side of the power connector (set turned off, no battery), whichever one shows 47R resistance (the other will be infinite) is the -ve.

28th Jan 2017, 7:38 am	#3
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Sinclair FTV1/B If you are making up a battery pack, why not put a diode in series inside to prevent any future destructive errors, you could allow for the volts drop in the pack make up. Or even better a fat diode in reverse across the + & - inside with a fuse in the supply to blow if connected wrongly.

28th Jan 2017, 9:25 am	#4
Courtney Louise Octode Join Date: Sep 2005 Location: Welshpool, Powys, Wales Posts: 1,327	Re: Sinclair FTV1/B How would you make a battery for one of these as I have a boxed one I would love to use on a battery. __________________ *33, 45, 78, around and around they go...*

28th Jan 2017, 9:34 am	#5
Jac Heptode Join Date: Jun 2006 Location: Eindhoven, Netherlands. Posts: 642	Re: Sinclair FTV1/B The middle pin is minus. The outer rim is plus. Jac

28th Jan 2017, 10:05 am	#6
60 oldjohn Dekatron Join Date: Dec 2004 Location: East Yorkshire, UK. Posts: 3,987	Re: Sinclair FTV1/B Keep it in the Airing cupboard for a month before powering up, Guess how I know! not a Sinclair and it was only AA batteries. A sickening fizz and an Ozone smell, I had the set from new and thought I would try it out again. John.

28th Jan 2017, 11:05 am	#7
Cobaltblue Moderator Join Date: Dec 2010 Location: Exeter, Devon and Poole, Dorset UK. Posts: 6,865	Re: Sinclair FTV1/B ISTR the original batteries were made by Poloroid, they were the same type that were used in the film packs. During the late 80's Greenweld in Southampton were selling these in pieces. Good tip from John about drying them out I have a couple in stores bought from Boot sales 20 years ago, Cheers Mike T __________________ Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk

28th Jan 2017, 2:26 pm	#8
Sideband Dekatron Join Date: Oct 2003 Location: Croydon, Surrey, UK. Posts: 7,571	Re: Sinclair FTV1/B I have one of these in working order. The only way I can get pictures is to connect the aerial to the RF out of a VCR. I'm working on a low-power UHF modulator with a range of a few 10's of feet __________________ There are lots of brilliant keyboard players and then there is Rick Wakeman.....