Mini LCD Analogue TVs - UK Vintage Radio Repair and Restoration Discussion Forum

Philips210 · 27th Sep 2017, 9:56 pm

Hi.

I have a number of small LCD analogue TVs (mainly Casio) and something occured to me, there's no coax aerial socket fitted nor any AV input facilities. There's just a telescopic aerial. I wonder if a signal from a UHF modulator can be efficiently coupled to the telescopic aerial. Any ideas or experiences on this matter?

As another thought, what about a very low power transmitter driven by composite video and audio signals? The RF signal would then be received as normal via the set's own telescopic aerial. Again, any suggestions welcome.

My plan would be to use a Goodmans digital set top box which has a built in UHF modulator.

Regards
Symon.

G6Tanuki · 27th Sep 2017, 10:00 pm

Quite a lot of these used a 3.5mm jack-plug as RF-input rather than the expected BNC or Belling-Lee coax socket.

These sockets are often confused with headphone sockets (usually by people plugging in headphones and complaining they can't hear anything!)

Clydeuk · 27th Sep 2017, 10:03 pm

I'm sure I saw a youtube video of someone using just the modulator from a VCR with no additional amplification and tuned in on one of these. Not sure what he used as an aerial for the "transmitter". He seemed to get a reasonable range

MrElectronicman · 27th Sep 2017, 11:08 pm

I have a mini CRT TV which came with an adapter for a 3.5mm plug to 300 Ohms balanced line and then to 75 Ohms F type TV plug

TonyDuell · 28th Sep 2017, 5:20 am

The service manuals for some of the Casio pocket LCD TVs are on Elektrotanya.

The 3.5mm (2 contact, 'mono') jack socket for the aerial seems to be wired so that the break contact disconnects the telescopic aerial, the sleeve is grounded and the tip is the signal (to the tuner input, in place of the telescopic aerial). Given that, if there's no such socket, I would have thought that feeding the UHF modulator signal to the telescopic aerial connection (remove the telescopic aerial to prevent it radiating, I guess) and the ground to the -ve side of the battery or somewhere would work.

For some unknown reason, the Casio model I bought a week ago (old, UK, PAL-I) has the socket, but it is not labelled on the case and has a plastic blanking cap fitted. The service manual shows it, and it seems to be used on other models. Quite why it wasn't a feature of the UK model I don't know. Licensing (does a portable set have to have an internal aerial or something)

Graham G3ZVT · 28th Sep 2017, 11:13 am

I can't remember why I took this picture of my Casio five years ago, but it does seem to address your question.

Graham.
G3ZVT

MonochromeMarc · 28th Sep 2017, 11:21 am

Hi Symon,

I plugged a piece of wire into the RF outlet of a modulator and laid the other end behind my mini telly's just to get this photo.....

Marc.

Herald1360 · 28th Sep 2017, 12:09 pm

Quote:

Originally Posted by TonyDuell

Licensing (does a portable set have to have an internal aerial or something)

ISTR that to count as portable (so you can use it anywhere on the strength of your home licence, it has to run on its own internal batteries. I don't think the aerial type matters.

Whether charging internal batteries whilst viewing is technically legal or not is a moot point. Chances of anyone caring are slim.

28th Sep 2017, 1:03 pm

A nice oddity with licensing is that ones staff in their independent living quarters are covered by ones TV licence.

I bet some posh lawyer wrote that bit in.

Philips210 · 28th Sep 2017, 4:46 pm

Hi.

Thanks for all your replies and for the pics from Marc and Graham and the link to electrotanya from Tony.

It seems then that it's not that critical coupling the signal to the set. I must admit not even trying any form of signal on these sets as I've had so many other things on the go. It's just that recently I came across one of my sets in the garage and realised there was only the telescopic aerial. I'll have to try and get one or two sets operational. I hope the surface mount electrolytics are OK, something I've been plagued with in the past with Canon camcorders.

Regards
Symon.

Philips210 · 28th Sep 2017, 5:08 pm

Hi

I just checked the Casio set in the garage and it's a model TV-1750 U and it does indeed have a 3.5mm jack socket for an external aerial. There's also the usual 3.5mm jack socket for headphones. The aerial socket isn't actually marked external aerial and it seems strange why Casio omitted marking the function of this socket on the casing.

I like the matched adapter that MrElectronicman has shown in his pic.

Regards
Symon

duncanlowe · 28th Sep 2017, 7:08 pm

Some years ago I had a Sony Watchman. No telescopic aerial, it was built into a neckband to hang it round your neck.

duncanlowe · 28th Sep 2017, 7:12 pm

About licensing, I think things might have changed. I say this because you are OK to use a TV in a touring caravan or motorhome, no matter whether its portable or a normal one, on the back of your home TV licence.

mark pirate · 29th Sep 2017, 8:42 am

I use a UHF transmitter for my analogue TV's, it accepts composite video and audio from a freeview box, VCR, ETC.
The range is pretty good, it certainly covers my house

I have two of these units, one in the house and one in the workshop.
I think they date from the late 80's, one I have had for years and the one pictured was a recent find from ebay.

Mark

27th Sep 2017, 9:56 pm	#1
Philips210 Nonode Join Date: May 2007 Location: Redruth, Cornwall, UK. Posts: 2,578	Mini LCD Analogue TVs Hi. I have a number of small LCD analogue TVs (mainly Casio) and something occured to me, there's no coax aerial socket fitted nor any AV input facilities. There's just a telescopic aerial. I wonder if a signal from a UHF modulator can be efficiently coupled to the telescopic aerial. Any ideas or experiences on this matter? As another thought, what about a very low power transmitter driven by composite video and audio signals? The RF signal would then be received as normal via the set's own telescopic aerial. Again, any suggestions welcome. My plan would be to use a Goodmans digital set top box which has a built in UHF modulator. Regards Symon.

27th Sep 2017, 10:00 pm	#2
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 14,005	Re: Mini LCD Analogue TVs Quite a lot of these used a 3.5mm jack-plug as RF-input rather than the expected BNC or Belling-Lee coax socket. These sockets are often confused with headphone sockets (usually by people plugging in headphones and complaining they can't hear anything!)

27th Sep 2017, 10:03 pm	#3
Clydeuk Hexode Join Date: Mar 2012 Location: Liverpool, Merseyside, UK. Posts: 453	Re: Mini LCD Analogue TVs I'm sure I saw a youtube video of someone using just the modulator from a VCR with no additional amplification and tuned in on one of these. Not sure what he used as an aerial for the "transmitter". He seemed to get a reasonable range

27th Sep 2017, 11:08 pm	#4
MrElectronicman Heptode Join Date: Feb 2011 Location: Washington DC, USA Posts: 619	Re: Mini LCD Analogue TVs I have a mini CRT TV which came with an adapter for a 3.5mm plug to 300 Ohms balanced line and then to 75 Ohms F type TV plug Attached Thumbnails __________________ David

28th Sep 2017, 5:20 am	#5
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,213	Re: Mini LCD Analogue TVs The service manuals for some of the Casio pocket LCD TVs are on Elektrotanya. The 3.5mm (2 contact, 'mono') jack socket for the aerial seems to be wired so that the break contact disconnects the telescopic aerial, the sleeve is grounded and the tip is the signal (to the tuner input, in place of the telescopic aerial). Given that, if there's no such socket, I would have thought that feeding the UHF modulator signal to the telescopic aerial connection (remove the telescopic aerial to prevent it radiating, I guess) and the ground to the -ve side of the battery or somewhere would work. For some unknown reason, the Casio model I bought a week ago (old, UK, PAL-I) has the socket, but it is not labelled on the case and has a plastic blanking cap fitted. The service manual shows it, and it seems to be used on other models. Quite why it wasn't a feature of the UK model I don't know. Licensing (does a portable set have to have an internal aerial or something)

28th Sep 2017, 11:13 am	#6
Graham G3ZVT Dekatron Join Date: May 2010 Location: Greater Manchester, UK. Posts: 18,724	Re: Mini LCD Analogue TVs I can't remember why I took this picture of my Casio five years ago, but it does seem to address your question. Graham. G3ZVT Attached Thumbnails

28th Sep 2017, 11:21 am	#7
MonochromeMarc Pentode Join Date: Jan 2015 Location: Wakefield, West Yorkshire, UK. Posts: 151	Re: Mini LCD Analogue TVs Hi Symon, I plugged a piece of wire into the RF outlet of a modulator and laid the other end behind my mini telly's just to get this photo..... Marc. Attached Thumbnails

28th Sep 2017, 1:03 pm	#9
Guest Guest Posts: n/a	Re: Mini LCD Analogue TVs A nice oddity with licensing is that ones staff in their independent living quarters are covered by ones TV licence. I bet some posh lawyer wrote that bit in.

28th Sep 2017, 4:46 pm	#10
Philips210 Nonode Join Date: May 2007 Location: Redruth, Cornwall, UK. Posts: 2,578	Re: Mini LCD Analogue TVs Hi. Thanks for all your replies and for the pics from Marc and Graham and the link to electrotanya from Tony. It seems then that it's not that critical coupling the signal to the set. I must admit not even trying any form of signal on these sets as I've had so many other things on the go. It's just that recently I came across one of my sets in the garage and realised there was only the telescopic aerial. I'll have to try and get one or two sets operational. I hope the surface mount electrolytics are OK, something I've been plagued with in the past with Canon camcorders. Regards Symon. Last edited by Philips210; 28th Sep 2017 at 4:48 pm. Reason: typo

28th Sep 2017, 5:08 pm	#11
Philips210 Nonode Join Date: May 2007 Location: Redruth, Cornwall, UK. Posts: 2,578	Re: Mini LCD Analogue TVs Hi I just checked the Casio set in the garage and it's a model TV-1750 U and it does indeed have a 3.5mm jack socket for an external aerial. There's also the usual 3.5mm jack socket for headphones. The aerial socket isn't actually marked external aerial and it seems strange why Casio omitted marking the function of this socket on the casing. I like the matched adapter that MrElectronicman has shown in his pic. Regards Symon

28th Sep 2017, 7:08 pm	#12
duncanlowe Nonode Join Date: Jan 2016 Location: Stafford, Staffs. UK. Posts: 2,532	Re: Mini LCD Analogue TVs Some years ago I had a Sony Watchman. No telescopic aerial, it was built into a neckband to hang it round your neck.

28th Sep 2017, 7:12 pm	#13
duncanlowe Nonode Join Date: Jan 2016 Location: Stafford, Staffs. UK. Posts: 2,532	Re: Mini LCD Analogue TVs About licensing, I think things might have changed. I say this because you are OK to use a TV in a touring caravan or motorhome, no matter whether its portable or a normal one, on the back of your home TV licence.

29th Sep 2017, 8:42 am	#14
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Mini LCD Analogue TVs I use a UHF transmitter for my analogue TV's, it accepts composite video and audio from a freeview box, VCR, ETC. The range is pretty good, it certainly covers my house I have two of these units, one in the house and one in the workshop. I think they date from the late 80's, one I have had for years and the one pictured was a recent find from ebay. Mark Attached Thumbnails