Philips X12T Portable (XT12 740/94) - UK Vintage Radio Repair and Restoration Discussion Forum

TV_Madness · 26th Dec 2009, 10:06 pm

Hi Guys

I Hope everyone had a good Christmas?

I found this little set when I was very young (11 maybe?!). Even back then I had a fascination with anything electrical, so didn't hesitate to pick it up... Sometimes I think it is amazing I'm even still alive, after whacking countless items of scrapped consumer electronics straight into the mains, without sparing a thought!! I seriously thought this one had been long since disposed of by my mother and her ferocious appetite for throwing anything and everything away, however I was wrong!

I have never managed to have a go at powering this set up, due to the odd shaped mains socket on the back. It is able to run from an external 12V source but again, I have never tried.

It also had the circuit diagram, neatly folded away next to the tuner, however this has been lost over the years. (Does anybody have a diagram for this set?)

Best Regards

Matt

Maarten · 26th Dec 2009, 10:23 pm

To find a schematic, it might prove useful to find out the complete model number first. X12T only says it's a 12" B/W TV.

TV_Madness · 26th Dec 2009, 10:25 pm

Ah OK

The Model (in full this time) is X12T 740/94

All the best

Danny · 27th Dec 2009, 12:01 am

Hi its in one of the newns red books i cant remember which on at the mo but will look over the next couple of days . these sets performed well but suffered from line lock problems . there is a mod which if i remember needed a chip change for the line osc.these used to be good for Dxing in the good old dayes and have vhf at 625 as well as normal uhf.
Danny

Maarten · 27th Dec 2009, 1:45 am

This model has a T4 chassis in it. A Dutch collector has the schematic on his site: http://84.87.34.146/Collectie/Televisie/x12t740.htm

TV_Madness · 27th Dec 2009, 3:20 pm

Brilliant. I did have a search on the net to see if I could locate something but failed. I obviously didn't look hard enough!

Thanks for the help

Matt

TV_Madness · 27th Dec 2009, 3:23 pm

Just noticed that if I'd taken the space out from between "X12T" and "740", that dutch page would have been the first hit. Doh!

ben · 30th Dec 2009, 2:04 am

I have one of these in the workshop, picked it up 3 years ago from a council 'bulky item pickup night'. Not yet connected mine up, your post has made me think I should get round to it. Got the KT3 to do first tho'!

TV_Madness · 30th Dec 2009, 8:44 pm

Hi Ben

I have actually managed to fire this set up powered from a 12v Switc mode PSU from a PC. I just haven't had any time to post an update with... The results:

Tuner/Vision & Sound IF Sections = Seem to be A-OK
Frame Osc and Output = Again, seem to be functioning as normal
Line Osc and Output = Line scan has shrunk into a 6 Inch wide band.

First, I checked the rellevant HT Rails, whcih all seem to be at (or close) to acceptable levels. After a bit of head scratching, I had noticed a rather smoked looking resistor like component connected in parallel with an Inductor across the Line scan coils.

I'll have another look at the Circuit after tea and find out what it is!!

All the best

TV_Madness · 30th Dec 2009, 9:58 pm

After closer inspection of the Line stage, it seems that the Resistor / Inductor circuit mentioned above is NOT in parallel with the Line scan coils at all. This circuit is in fact connected in series with the Collector of the AU113 (Line Output Transistor) and the primary of the LOPT. They're soldered across two spare terminals on a Plug that brings the Line/Frame scan outputs up to the deflection coils. Upon first inspection, it looked as though they were connected across the terminals for the two leads up to the Line scan coils. Time for an opticians appointment I think!

At a guess, I'd say this is some form of safety measure, so that if the plug for the deflection coils were to be disconnected, it would cut off the drive to the LOPT? Maybe?

Looking at the circuit, these components do not exist at all, and there is simply a straight connection from the Collector to the Primary of the LOPT.

I don't suppose you could pop the back off of yours Ben if you get a spare 5 Mins and just check to see if these components exist in yours?

Attached is the circuit for the Line Stage.

Best Regards

Matt

26th Dec 2009, 10:06 pm	#1
TV_Madness Pentode Join Date: Jan 2008 Location: Titchfield Common, Hampshire, UK. Posts: 245	Philips X12T Portable (XT12 740/94) Hi Guys I Hope everyone had a good Christmas? I found this little set when I was very young (11 maybe?!). Even back then I had a fascination with anything electrical, so didn't hesitate to pick it up... Sometimes I think it is amazing I'm even still alive, after whacking countless items of scrapped consumer electronics straight into the mains, without sparing a thought!! I seriously thought this one had been long since disposed of by my mother and her ferocious appetite for throwing anything and everything away, however I was wrong! I have never managed to have a go at powering this set up, due to the odd shaped mains socket on the back. It is able to run from an external 12V source but again, I have never tried. It also had the circuit diagram, neatly folded away next to the tuner, however this has been lost over the years. (Does anybody have a diagram for this set?) Best Regards Matt Attached Thumbnails __________________ I don't want anymore junk in this house!

26th Dec 2009, 10:23 pm	#2
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,203	Re: Philips X12T Portable To find a schematic, it might prove useful to find out the complete model number first. X12T only says it's a 12" B/W TV.

26th Dec 2009, 10:25 pm	#3
TV_Madness Pentode Join Date: Jan 2008 Location: Titchfield Common, Hampshire, UK. Posts: 245	Re: Philips X12T Portable Ah OK The Model (in full this time) is X12T 740/94 All the best __________________ I don't want anymore junk in this house!

27th Dec 2009, 12:01 am	#4
Danny Heptode Join Date: Jul 2003 Location: North Walsham, Norfolk, UK. Posts: 516	Re: Philips X12T Portable Hi its in one of the newns red books i cant remember which on at the mo but will look over the next couple of days . these sets performed well but suffered from line lock problems . there is a mod which if i remember needed a chip change for the line osc.these used to be good for Dxing in the good old dayes and have vhf at 625 as well as normal uhf. Danny

27th Dec 2009, 1:45 am	#5
Maarten Dekatron Join Date: Dec 2007 Location: Haarlem, Netherlands Posts: 4,203	Re: Philips X12T Portable This model has a T4 chassis in it. A Dutch collector has the schematic on his site: http://84.87.34.146/Collectie/Televisie/x12t740.htm

27th Dec 2009, 3:20 pm	#6
TV_Madness Pentode Join Date: Jan 2008 Location: Titchfield Common, Hampshire, UK. Posts: 245	Re: Philips X12T Portable Brilliant. I did have a search on the net to see if I could locate something but failed. I obviously didn't look hard enough! Thanks for the help Matt __________________ I don't want anymore junk in this house!

27th Dec 2009, 3:23 pm	#7
TV_Madness Pentode Join Date: Jan 2008 Location: Titchfield Common, Hampshire, UK. Posts: 245	Re: Philips X12T Portable Just noticed that if I'd taken the space out from between "X12T" and "740", that dutch page would have been the first hit. Doh! __________________ I don't want anymore junk in this house!

30th Dec 2009, 2:04 am	#8
ben Dekatron Join Date: Aug 2006 Location: Madrid, Spain / Wirral, UK Posts: 7,498	Re: Philips X12T Portable (XT12 740/94) I have one of these in the workshop, picked it up 3 years ago from a council 'bulky item pickup night'. Not yet connected mine up, your post has made me think I should get round to it. Got the KT3 to do first tho'! __________________ Regards, Ben.

30th Dec 2009, 8:44 pm	#9
TV_Madness Pentode Join Date: Jan 2008 Location: Titchfield Common, Hampshire, UK. Posts: 245	Re: Philips X12T Portable (XT12 740/94) Hi Ben I have actually managed to fire this set up powered from a 12v Switc mode PSU from a PC. I just haven't had any time to post an update with... The results: Tuner/Vision & Sound IF Sections = Seem to be A-OK Frame Osc and Output = Again, seem to be functioning as normal Line Osc and Output = Line scan has shrunk into a 6 Inch wide band. First, I checked the rellevant HT Rails, whcih all seem to be at (or close) to acceptable levels. After a bit of head scratching, I had noticed a rather smoked looking resistor like component connected in parallel with an Inductor across the Line scan coils. I'll have another look at the Circuit after tea and find out what it is!! All the best __________________ I don't want anymore junk in this house!

30th Dec 2009, 9:58 pm	#10
TV_Madness Pentode Join Date: Jan 2008 Location: Titchfield Common, Hampshire, UK. Posts: 245	Re: Philips X12T Portable (XT12 740/94) After closer inspection of the Line stage, it seems that the Resistor / Inductor circuit mentioned above is NOT in parallel with the Line scan coils at all. This circuit is in fact connected in series with the Collector of the AU113 (Line Output Transistor) and the primary of the LOPT. They're soldered across two spare terminals on a Plug that brings the Line/Frame scan outputs up to the deflection coils. Upon first inspection, it looked as though they were connected across the terminals for the two leads up to the Line scan coils. Time for an opticians appointment I think! At a guess, I'd say this is some form of safety measure, so that if the plug for the deflection coils were to be disconnected, it would cut off the drive to the LOPT? Maybe? Looking at the circuit, these components do not exist at all, and there is simply a straight connection from the Collector to the Primary of the LOPT. I don't suppose you could pop the back off of yours Ben if you get a spare 5 Mins and just check to see if these components exist in yours? Attached is the circuit for the Line Stage. Best Regards Matt Attached Thumbnails __________________ I don't want anymore junk in this house!