UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Test Gear and Workshop Equipment

Notices

Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders.

Reply
 
Thread Tools
Old 11th Mar 2022, 6:28 pm   #21
See_Mos
Hexode
 
See_Mos's Avatar
 
Join Date: Nov 2003
Location: Ossett, West Yorkshire, UK.
Posts: 476
Default Re: Television Magazine Testcard Generator

As usual I should have slowed down and read the data sheets properly.

The MC1377 is not easily interfaced because it needs inverted luminance, the output from the pattern generator is positive.

I don't think AD723, AD724 or CXA165 can be used, there is no access to the luminance circuit because the luma is generated internally. The kit that I ordered will come in useful if I ever get around to a new design.

So far the TEA1002 looks to be the best option though it does need a luminance amplifier to boost and level shift the 400mV from the logic card.
See_Mos is offline   Reply With Quote
Old 17th Mar 2022, 8:38 pm   #22
Philips210
Nonode
 
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,546
Default Re: Television Magazine Testcard Generator

Hi

With the help from See Mos who kindly sent me several high resolution pics of his logic board, I've been able to check the PCB foil against the circuit diagram.

Quite a few errors were found in the circuit which I've now corrected using MS Paint, not perfect by any means, but keeps the circuit looking reasonable and original.
Having the correct circuit I can then draw the circuit diagram with KiCad and then go on to lay out the PCB. Before doing this, I will build a breadboard version which will take a considerable time due to the high component count.

I also intend to build an alternative PAL encoder to the published circuit which used the TBA520/TBA540 combination. The TEA1002 or TEA2000 ICs look to be good options.

Please see attached pics of the corrections to the logic board which I hope will help anyone wanting to build this circuit. The resolution does not look good due to the files being resized by the forum software. I can send anyone higher res copies if required.


Regards,
Symon
Attached Thumbnails
Click image for larger version

Name:	cpg79001.jpg
Views:	177
Size:	82.8 KB
ID:	253744   Click image for larger version

Name:	cpg79002.jpg
Views:	154
Size:	69.1 KB
ID:	253745   Click image for larger version

Name:	corrections001.jpg
Views:	120
Size:	72.9 KB
ID:	253746   Click image for larger version

Name:	corrections002.jpg
Views:	97
Size:	136.4 KB
ID:	253747  
Philips210 is offline   Reply With Quote
Old 19th Mar 2022, 12:03 am   #23
George Cooper
Triode
 
Join Date: Feb 2022
Location: Falkirk, Stirlingshire, Scotland, UK.
Posts: 25
Default Re: Television Magazine Testcard Generator

I also still have a "Mannor Supplies" pattern generator, still works. For better UHF output I strapped a modulator from a Panasonic VCR onto it, worked a treat.

I have no use for it so if anyone wants it you're welcome.
George Cooper is offline   Reply With Quote
Old 19th Mar 2022, 1:53 pm   #24
Wendymott
Octode
 
Wendymott's Avatar
 
Join Date: Jun 2013
Location: Huddersfield, West Yorkshire, UK.
Posts: 1,769
Default Re: Television Magazine Testcard Generator

Hi See Mos. I have looked at the patterns generated and it looks identical to the very first pattern generator I bought for the embryo NEI TV factory in Bradford. It was made by a guy at Microvitec , which again was based in Bradford.. Yes it was full of TTL Logic. Fortunately we were "Given" a PM5518 innards from the Grundig factory, so whatever happened to the original, I know not.
__________________
Should get out more.

Regards
Wendy G8BZY
Wendymott is offline   Reply With Quote
Old 24th Mar 2022, 1:47 pm   #25
George Cooper
Triode
 
Join Date: Feb 2022
Location: Falkirk, Stirlingshire, Scotland, UK.
Posts: 25
Default Re: Television Magazine Testcard Generator

Just to say the Mannor Supplies Pattern generator is now spoken for.
George Cooper is offline   Reply With Quote
Old 24th Mar 2022, 7:14 pm   #26
Chris55000
Nonode
 
Join Date: Aug 2007
Location: Walsall Wood, Aldridge, Walsall, UK.
Posts: 2,826
Default Re: Television Magazine Testcard Generator

Hi!

I seem to remember that you could get the full–size artworks for the PCBs, but you had to write to Television's Editorial Office with a £2.50 Cheque or Postal Order – there was no such things as Artwork PDF files in those days!

Chris Williams

PS!

The Service Manual for the Philips PM5518 Colour Pattern Generator suggests the same means of verifying the function of the pattern logic circuits by lifting the video i/p to the UHF Modulator and using this as a ready–made video probe, a method also quoted by Malcolm Burrell in his T.C.G. plans!
__________________
It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!

Last edited by Chris55000; 24th Mar 2022 at 7:23 pm.
Chris55000 is offline   Reply With Quote
Old 8th May 2022, 11:48 pm   #27
Philips210
Nonode
 
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,546
Default Re: Television Magazine Testcard Generator

Hi.

An update on the project so far.

I've provisionally drawn the circuit diagram with KiCAD for the Colour Pattern Generator (May to July 1979) and also the PCB layout.

I also made a few mods to the circuit diagram and PCB layout so that either the original TBA520/TBA540 or the updated TEA1002 PAL encoders can be easily connected. The modified circuit uses a 12-way Molex connector as opposed to the original 10-way one.
Please see attached pics.
I intend proving the circuit on breadboard in due course.

Recently, I've been very busy experimenting with the TEA1002 PAL encoder circuits. I built a breadboard version of Malcolm Burrell's Simple Colour Pattern Generator, Television magazine, February 1990. It uses a ZNA234 Sync pulse generator to provide the Composite sync and blanking waveforms required by the TEA1002 but I'm having a problem with no colour. I have thoroughly checked the circuit for errors but can't find any.
Checking the composite video colour bar waveform feeding the monitor, the signal appears to be correct. The step wedge shows colour information on the yellow, cyan, green, magenta and red bars. The colour burst is present.

The TEA1002 requires a Burst enable signal or Colour Burst Flag (CBF) which is derived from the inverted composite sync waveform by using two monostables. I've carefully checked the width of the colour burst and its position in the back porch period which seems correct. If the 8.867MHz reference oscillator trimmer cap is adjusted through its range, some disturbance can be seen on the screen. Also the colour information on the video signal including the burst disappear and reappear. The 7.8kHz PAL switch signal also appears to be correct. I would think the TEA1002 is faulty but tried another which shows the same fault. Both faulty in the same way, possible but I'm not so sure. I have on rare occasions briefly noticed horizontal rainbow colours akin to the reference oscillator being off frequency.
It occured to me that perhaps the reason could be due to using a breadboard layout but I've built this circuit quite neatly and think it should be OK but nevertheless still a doubt.

I read something interesting about logic gate oscillators not being the best way to generate a clock signal. Apparently there can often be spurious operation with these circuits. I built a discrete version using a 10MHz crystal which works well but didn't make any difference to the no colour fault.
I had wondered if the ZNA234's timing is out. Checking the clock signal feeding it seems to show all's well. I even knocked up a ZNA134 circuit to provide the sync and blanking signals but still the same no colour fault.

I have been running around in circles on this project and progress has been a little slow.

A couple of days ago I even tried out the newer PAL encoder using a TEA2000 and guess what, no colour! Two more TEA2000s and still the same.
One would think the monitor has to be the cause but feeding the monitor with a freeview signal proves it's capable of displaying a colour signal.
There must be something I am missing about the composite video signal but it does look normal.

Today, I built the Elektor Video Syncbox, February 1984 issue. It uses half a dozen CMOS ICs to provide most of the signals required by the TEA1002. Initial checks using the 'scope proves it's working. Tomorrow, I intend to try this circuit with a TEA1002 to see the outcome.

It's been quite a tedious project but I'm still learning a lot in the process and hope to crack it soon. I'll probably order some more TEA1002s just incase.
I'll try to provide some pics of the circuits tomorrow.
Sorry for the long post but if anyone has any ideas about the no colour fault with the TEA1002 I'd be very interested. Thanks.

Regards,
Symon
Attached Thumbnails
Click image for larger version

Name:	cpg79.jpg
Views:	138
Size:	118.7 KB
ID:	256813   Click image for larger version

Name:	cpg79_pcb.jpg
Views:	133
Size:	123.0 KB
ID:	256814   Click image for larger version

Name:	cpg79_rev.jpg
Views:	116
Size:	115.8 KB
ID:	256815   Click image for larger version

Name:	cpg79_pcb_rev.jpg
Views:	101
Size:	132.2 KB
ID:	256816  

Last edited by Philips210; 9th May 2022 at 12:10 am. Reason: correction
Philips210 is offline   Reply With Quote
Old 10th May 2022, 10:49 am   #28
jdavis6809
Tetrode
 
Join Date: Jun 2013
Location: Blackpool, Lancashire, UK.
Posts: 51
Default Re: Television Magazine Testcard Generator

hello,

I use a Fluke 54200 TV Signal Geerator PAL NTSC SECAM plus multi patterns (£200)

regards

john davis uk
jdavis6809 is offline   Reply With Quote
Old 10th May 2022, 1:05 pm   #29
gezza123
Heptode
 
gezza123's Avatar
 
Join Date: Mar 2010
Location: Eastham, Wirral, Merseyside, UK.
Posts: 785
Default Re: Television Magazine Testcard Generator

HI.Philips210
Found this data it may help you.
Excellent work, can't wait to see it finished.
Attached Files
File Type: pdf g_glthermisters.pdf (236.5 KB, 92 views)
gezza123 is offline   Reply With Quote
Old 10th May 2022, 3:39 pm   #30
Philips210
Nonode
 
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,546
Default Re: Television Magazine Testcard Generator

Thanks gezza123, that's very helpful info on the thermistor.

Best regards,
Symon
Philips210 is offline   Reply With Quote
Old 21st Aug 2022, 11:06 pm   #31
Philips210
Nonode
 
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,546
Default Re: Television Magazine Testcard Generator

Just a small update on the testcard project.

I've almost completed assembly of the Breadboard version of the logic board. This has been quite an ambitious task. It has 12 breadboards locked together so that the 46 ICs can be positioned in roughly the same way as the PCB version.
In pic 2, the top left IC is the ZNA134E sync pulse generator together with its 2.5625MHz crystal.

To keep things cool, I've used a 5V regulator on each of the 12 breadboards. I might even adopt this on the final PCB if it is successful.
It has taken a long time to build this and hope it all turns out favourably. My main concern is possible problems due to fairly long interconnections, maybe extra wiring inductance and stray capacitance effects.

I am now going to build the original PAL encoder using the TBA520/TBA540 IC combination as per the magazine design. This will be on a matrix board for evaluation before committing to a PCB. For the subcarrier reference coil, I'll be using one from a Philips G11 decoder kindly sent to me by Glyn (Welsh Anorak). The original TV magazine circuit used one from the GEC 2110 series decoder.
I have also built on matrix board an alternative TEA1002 encoder which is working well. I hope to test the logic breadboard circuit with the two different encoders in the coming weeks.

Please see attached pics of the logic circuit breadboard layout which just needs a few more components and a thorough check before testing.

Regards,
Symon
Attached Thumbnails
Click image for larger version

Name:	IMGP8548.jpg
Views:	137
Size:	101.9 KB
ID:	263325   Click image for larger version

Name:	IMGP8549.jpg
Views:	145
Size:	141.1 KB
ID:	263326   Click image for larger version

Name:	IMGP8550.jpg
Views:	124
Size:	156.0 KB
ID:	263327   Click image for larger version

Name:	IMGP8551.jpg
Views:	127
Size:	147.8 KB
ID:	263328  

Last edited by Philips210; 21st Aug 2022 at 11:30 pm.
Philips210 is offline   Reply With Quote
Old 22nd Aug 2022, 12:33 am   #32
Philips210
Nonode
 
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,546
Default Re: Television Magazine Testcard Generator

Forgot to mention in the previous post, the problem I had with no colour on the TEA1002 encoder was due to two things. Firstly, stray capacitance effects by using a Breadboard layout. Constructing this encoder on matrix pad board basically solved the problem. The critical area was around the 8.867MHz crystal oscillator.

Secondly, there was a problem with the circuit from Malcolm Burrell's Simple Colour Pattern Generator, Television mag, Feb 1990. The PAL switch timing was wrong. By adopting the circuit by Tony Jenkins TV mag June 1984 which uses a 4528 monostable and 4013 F/F the encoder finally produced good colour. The M. Burrell circuit needed an extra monostable feeding the 7474 F/F to function. I used a 74121 which did the trick nicely. I'll post some pics of my mods in due course.

Please see attached pic of the testbed TEA1002 encoder. It's basically M Burrell's Feb 1990 circuit but using the above mentioned circuit mod by T Jenkins. Alongside the 'scope probe is the 4013 F/F for PAL switching and a 4528 monostable for the Colour Burst Flag (CBF) signal. Also pics of the displayed colour bars and CVBS signal on the 'scope. When I link this encoder to the Testcard generator logic board I won't be using the colour bar circuitry from this board, just the TEA1002 part of the circuit.

Regards,
Symon
Attached Thumbnails
Click image for larger version

Name:	IMGP8434.jpg
Views:	166
Size:	108.8 KB
ID:	263331   Click image for larger version

Name:	IMGP8459.jpg
Views:	146
Size:	32.8 KB
ID:	263332   Click image for larger version

Name:	IMGP8435.jpg
Views:	135
Size:	49.3 KB
ID:	263333  

Last edited by Philips210; 22nd Aug 2022 at 12:38 am.
Philips210 is offline   Reply With Quote
Old 22nd Aug 2022, 3:43 pm   #33
Chris55000
Nonode
 
Join Date: Aug 2007
Location: Walsall Wood, Aldridge, Walsall, UK.
Posts: 2,826
Default Re: Television Magazine Testcard Generator

There seems to be a one or two chaps who have trouble getting colour out of a TEA1002 when used with the ZNA234 – I'll have to check how Manor Supplies did it in their Mk.5 – I have two, one on loan from Glyn that I'm checking out for an "intermittent ghost crosshatch" and another one not tested yet thanks to the kind generosity of another Forum Member!

Main thing is I need to get that Mk. 5 circuit properly drawn up on my sPlan as soon as I have spare time, so I can see exactly how M.S. solved it!

Chris Williams
__________________
It's an enigma, that's what it is! This thing's not fixed because it doesn't want to be fixed!
Chris55000 is offline   Reply With Quote
Old 22nd Aug 2022, 3:51 pm   #34
Wendymott
Octode
 
Wendymott's Avatar
 
Join Date: Jun 2013
Location: Huddersfield, West Yorkshire, UK.
Posts: 1,769
Default Re: Television Magazine Testcard Generator

Hi Chris. Just a thought...... I designed and built a "Line delay generator" when making my PIC based pattern generator...... it was VERY useful to see any errors on any line .. it was PIC Based and worked well..... I did dismantle it..... but I still have the SCH and software... contact me if needed.
__________________
Should get out more.

Regards
Wendy G8BZY
Wendymott is offline   Reply With Quote
Old 22nd Aug 2022, 4:36 pm   #35
Philips210
Nonode
 
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,546
Default Re: Television Magazine Testcard Generator

That sounds good Chris.

The interest in the Manor Supplies circuit is not connected with this project but I am always interested in pattern generator circuits and enjoy experimenting with them. I've also built the "Diagnostic Pattern Generator" by Malcom Burrell, Television, August 1978 issue. This is currently on breadboard and is working welll. I'll put some pics up soon.

The main reason I went to the trouble of building the May 1979 circuit on Breadboard rather than on matrix board or a PCB was so I could extend its pattern options. The plan is to build everything to the project spec and get that working first. Then try the TEA1002 encoder. After that I intend to experiment with a circle generator and add a chequerboard and frequency grating patterns, also colour bars and colour rasters with selectable RGB control.
If all goes to plan I might use electronic switching for the various pattern options and possibly infra-red remote control using the Mullard 5000 system.

One thing I will say is it's not a good idea building the PAL encoder on breadboard. I had huge problems with instability so built the TEA1002 encoder on matrix board. I also built the later TEA2000 encoder, again had problems on breadboard but works reliably on matrix board.

As I say, I have reliable colour from the TEA1002 now by using the circuit Tony Jenkins used in his testcard project May to July 1984. It used 4013 and 4528 CMOS ICs for the PAL switch and CBF signals obtained from the inverted composite sync signal. There's no way the circuit in the Feb 1990 issue can work. The PAL switch timing is awry. I modified this basically following T Jenkins circuit by adding a 74121 monostable that feeds the 74LS74 F/F and that worked reliably thereafter.

What M Burrell did with his Feb 1990 circuit was to use two monostables which not only sets the CBF signal pulse width but also the delay, ie its position within the back porch. I think this is an advantage.

Incidentally most TEA1002 circuits seem to follow a very similar approach to the T Jenkins's circuit for PAL switch and CBF signal generation. I think the PE Teletext decoder from 1980, the Ayr Teletext decoder and Manor Supplies MkV pattern generator seem to use this 4013/4528 combination which is reliable.

Regards,
Symon

Last edited by Philips210; 22nd Aug 2022 at 4:42 pm.
Philips210 is offline   Reply With Quote
Old 23rd Aug 2022, 11:08 am   #36
See_Mos
Hexode
 
See_Mos's Avatar
 
Join Date: Nov 2003
Location: Ossett, West Yorkshire, UK.
Posts: 476
Default Re: Television Magazine Testcard Generator

As mentioned previously, I had drifting problems with the original encoder for Malcolm Burrell's test card generator so I adopted a TEA1002 encoder that worked reasonably well even though I did not have the delay components. The Mullard data sheet shows how to do this.

This was many years ago and long before PCB cad. I had made the board using an etch resist pen. The components were spread out and the tracks were very ragged. Symon reawakened my interest in the TCG and having a commercial repair to do that needed a new PCB I also designed a new encoder board based on my version of the TEA1002. The minimum quantity from Elecrow was 5 pieces but I received 11. i used one myself and sent a couple to Symon so I have eight spares if anyone would like any. I will put them is the for Sale area when I get around to it.

Without the delay line components and mixing the luminance from the logic card after the encoder the colour fit is not 100% but there is also the same delay on the letter box so I decided to make a line delay / scope sync generator to closer inspect single lines of the test card.

I haven't started that project yet as I got distracted by the idea of recreating Malcolm Burrell's test card using a Microchip PIC and an AD724 encoder IC. I am almost there. I have two LCD TV's available for testing. On one there is a glitch a couple of lines below the colour bars but not on the other TV . It would be interesting to see the display on an older TV with a tube.

I'll post some pictures later, on here and on the Positron PIC Basic Compiler website.
See_Mos is offline   Reply With Quote
Old 23rd Aug 2022, 12:34 pm   #37
Philips210
Nonode
 
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,546
Default Re: Television Magazine Testcard Generator

Sounds like you're making good progress with your PIC version Trevor. It will be good to see that working.

I am also going to build another TEA1002 encoder using the PCB that you kindly sent to me. The AD724 encoder looks good and I'll look into that option as well. Its main advantage as you pointed out, is there's no requirement for special delay and filter components.
With my encoder, the colour bars look very good on a LCD display showing good chroma/luminance registration. On the Philips televideo CRT set, the display isn't so crisp. I'll have to check that TV to ascertain whether the internal switching is normal. The IF stages may not be isolated possibly causing smearing of the display for example.

One quick question. When you originally built the Testcard generator, did you have to tailor the values of the resistors in any of the monostable circuits?
I found that I did have to do this with the Diagnostic Pattern Generator TV Mag Aug 1978 issue.

Regards,
Symon
Philips210 is offline   Reply With Quote
Old 23rd Aug 2022, 2:11 pm   #38
Philips210
Nonode
 
Join Date: May 2007
Location: Redruth, Cornwall, UK.
Posts: 2,546
Default Re: Television Magazine Testcard Generator

Quote:
Originally Posted by See_Mos View Post
As mentioned previously, I had drifting problems with the original encoder for Malcolm Burrell's test card generator
Hi Trevor.

One thing I've noticed with the TBA540 4.43MHz crystal oscillator in the following TVs: Philips G11, GEC 2110, ITT CVC20/25/30/32/40/45 and Pye 713/725/731 etc is that they all agree with the Mullard application data.
M Burrell's set up with this IC is different, he's connected pins 1 and 2 together and the crystal is going to ground. Maybe it's because it is being used in an encoder rather than its usual decoder role. Pin 1 is for amplitude control.

Also the chroma modulator IC, TBA 520 did get superceded by Mullard. It was replaced with the TBA990. I wondered if that would further improve the original encoder. I'll have to read up on these ICs and do some tests.

Just one more thing, as Columbo famously said , I had thought about whether the make of the IC is important. I've got both Mullard and Telefunken made TBA540s and just a Telefunken TBA520. I know there were problems with later single chip decoders that used the TDA3562 when I used to repair TVs but don't recall it being a problem with earlier decoders.

Regards,
Symon
Philips210 is offline   Reply With Quote
Old 25th Aug 2022, 10:37 am   #39
Wendymott
Octode
 
Wendymott's Avatar
 
Join Date: Jun 2013
Location: Huddersfield, West Yorkshire, UK.
Posts: 1,769
Default Re: Television Magazine Testcard Generator

Hi Peeps. After a bit of "To ing and Fro ing" After I posted that I had the full info for the TV Line Delay generator....... I couldnt find it. Well to cut a long story blah blah..I found it last night and scanned it. It is 9 pages of PDF zipped into 4+M file. If any one wants it.. please PM me.
__________________
Should get out more.

Regards
Wendy G8BZY
Wendymott is offline   Reply With Quote
Old 26th Aug 2022, 4:05 pm   #40
See_Mos
Hexode
 
See_Mos's Avatar
 
Join Date: Nov 2003
Location: Ossett, West Yorkshire, UK.
Posts: 476
Default Re: Television Magazine Testcard Generator

Here are the pictures of the project so far. The code for the Microchip PIC is written almost entirely in Positron PIC Basic.

Picture 1 is a copy of the original magazine cover.

Picture 2 is the result from the original logic cart together with the new AD724 colour encoder as seen on my Daewoo 4:3 LCD TV

Picture 3 is from the Microchip project together with a AD724 encoder. Note the glitch just below the colour bars, this does not appear on a cheap Techwood LCD TV but as it is not present with the original logic card there has to be a problem with the code even though everything appears to be OK when checked with a Picoscope. Note the extra white line below and above the castellations.

Picture 4 shows the test setup. Only PortB is needed to drive the AD724, PortC is used for various test signals during development and testing with a previous TEA1002 encoder which needed more logic signals.

There is some camera distortion of the pictures and the shading is due to LCD viewing angles.
Attached Thumbnails
Click image for larger version

Name:	Picture 1.JPG
Views:	112
Size:	83.1 KB
ID:	263654   Click image for larger version

Name:	Picture 2.jpg
Views:	114
Size:	70.1 KB
ID:	263655   Click image for larger version

Name:	Picture 3.jpg
Views:	123
Size:	52.1 KB
ID:	263656   Click image for larger version

Name:	Picture 4.jpg
Views:	121
Size:	100.8 KB
ID:	263657  
See_Mos is offline   Reply With Quote
Reply

Thread Tools



All times are GMT +1. The time now is 6:19 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.