Strange colour problem , Ferguson FL15DX5 LCD tv

[ProDave]

This one's got me stumped.

It's a small 15" ferguson LCD tv with built in freeview. I've fixed the original, tripping PSU problem only to find it has a strange colour problem.

Everything is fine on analogue tv , the composite AV inputs and PC VGA input.

But, when you switch over to DTV mode it has an obvious colour fault, everything has a strong purple colour. This fault is also evident if using the scart input from an RGB source

At first glance, it looks like no green, but it's not that simple. Whites are white, so green is there. But what should be black is purple. So anything in between gets progressively less green, the darker it is if that makes sense. Turn the colour right down and it's a perfect black and white picture.

Is this a know fault or anyone got any ideas?

Clearly it's not worth spending much time or money on this one but it's more a case of not wishing to be defeated.

I've searched the net and found mention of this very same fault, but with no resolution being found.

[daz]

this sounds very similar to a common fault on the samsung lcd tvs, where after psu is repaired the analoge pic is fine but the digital pic has a green tint to it but the digital menu is fine, all this is caused by a corrupt eeprom.
hope this helps
daz

[ProDave]

Thanks daz.

That might help, if only I could find a service manual for this set, or at the very least find the sequence to access the engineers menu's and some information on at least some of the parameters.

Anyone know this information?

[ProDave]

Another bit to this one.

I've not done anything with it for a while, but had another go at it today.

I still can't find how to access the service menu's?  But what I did find is holding down the "menu" button while powering up puts it into "debug mode" But apart from saying "debug mode" in the top left corner, I haven't found anything usefull that it will do in that mode.

Another interesting test, I connected a scart lead from this set to another tv.  The other tv displays whatever is on the screen of this set.  When in "DTV" mode, the other set displays a perfect picture from freeview.

So the fault is not with the "freeview receiver" in this set, it purely lies with it's inability to correctly dispaly an RGB source (which must be how the internal freeview decoder is linked to the rest of the tv)

Any more ideas anyone, particularly how to access the service menu's?

[norman]

Hi, only info I can find, to enter service mode, press menu on remote control and front panel simultaneously, to exit service press standby. Please make a note of settings in service mode before you change anything. Hope this helps, Norman

[ProDave]

Thanks for that.  I had kind of figured that out but not the exact button sequence.

Now in service mode.

When in Dtv mode, it brings up settings for "YCbCr" so I presume that's how the DTV decoder is connected.

There are settings for R Gain, G Gain, B Gain, R Bias, G Bias and B Bias.

I can get pretty close to a normal picture by cranking up G bias (all bias settings are at zero initially) to something much much higher, and tweaking G gain.

So there might be hope for this set yet.

It still seems to me though, I'm patching up a problem rather than fixing it.

Next problem.  How do I get a DTV test card or colour bars?  I certainly don't have a DTV pattern generator.

I'll try the same with an RGB scart input where I can more easilly get a test card to play with.  When I get more time that is.

[tsgunnell]

You can display the test card on any reasonably new Freeview receiver
using the following steps. Note that some older set top boxes do not
fully conform with the specifications and may be unable to access this
service.

1. Tune to the BBCi channel (currently ch. 105)
2. When the BBCi background appears, press Yellow (within 30 secs)
3. Tune away to a different channel
4. Tune back to the BBCi channel (currently ch. 105)
5. When the BBCi background appears, press Green (within 30 secs)
The word 'Secret' will appear in the top right hand corner
6. Wait until the status page appears
7. Enter 3, 3, 5, 8, 2, Red, Green, Yellow, Blue
(note "33582" spells out the word "DELTA" on a mobile phone keypad)
8. Wait approximately 30 seconds
Test card will appear

[sparky]

hi
mine is the thomson top up box 6months old
 tried the test card set up works except after 33582
all i pressed  was green button test card appears
like the good old days with test card playing away
sparky

[ProDave]

Thanks that works. But..

Press Red, Green and Yellow ONLY.  Pressing blue brings up a page of "credits" about the designers that you can't then remove.

Anyway, I've now given up on this tv for a number of reasons.

Firstly, while I can vastly improve the picture problems on freeview, I can't get it correct.

Secondly, I have determined this is a really c**p tv, even when working.  The freeview tuner keeps dropping channel 5 from it's channel list unless you rescan mux 2, then it comes back but only for a while.

Thirdly, on freeview, the lip sync is abysmal, and the picture shows far too much noticable compression artifacts, something you shouldn't see on such a small screen.

So I'll be selling this one again, and to be fair to buyers it will be described as faulty

[jurq]

Hi,
I've just read this topic-> this is common problem in this TV. In this TV white balance settings for DTV are not the same as analog inputs, you can set it in service mode (all settings are in EEPROM). Do you have EEPROM/FLASH Programmer?

[ProDave]

Hi,
I've just read this topic-> this is common problem in this TV. In this TV white balance settings for DTV are not the same as analog inputs, you can set it in service mode (all settings are in EEPROM). Do you have EEPROM/FLASH Programmer?

In service mode (when in DTV) there are settings for R bias, G bias and B bias, as well as R gain, G gain and B gain.

By default all bias settings were 0, and all gain settings around 100 give or take a bit.

By increasing G bias to about 100 i've got a vastly improved, but still not correct picture.  It looks fairly okay on the BBC test card, but "real pictures" reveal that dark scenes are still pretty poor.

Are there any other setting you are thinking of? that's all I have found so far.  I don't have an eeprom programmer.

I still get the feeling this set has a fault, and adjusting the settings like this is just patching it up.

This set is driving me nuts.  Another "quirk" is every time you exit from service mode, I find it's deleted all the stored analogue channels, and the user brightness, colour and contrast setting have gone back to some default with colour saturation way way too high. All adding to the time taken to test each adjustment.

Oh, and the PSU has started tripping again, but ONLY in analogue tv mode? perhaps it wasn't just some duff capacitors after all.

[jurq]

I found out in one 17' Ferguson there were separate settings for analog and digital, that means new software was in some 17' models. What I did? The new software is in FLASH memory, the settings for RGB A/D converters in EEPROM then put new software from 17' FLASH memory to 15' (the picture was too big) and set white balance for DVB after that I put old 15' software to FLASH but new settings for A/D converters for DVB were wrtitten to EEPROM and the picture is perfect. Only what you need is hot air station, good programmer and dumps for FLASH (I got it :cheesy1:!) This is my patent and it work 100%.
Good Luck!

[ProDave]

So you are saying the only way to properly fix this fault is to reprogram the eeprom by taking it out of the set.

Far too much work, even if I had the equipment.

So are you also saying the parameters that need changing are not available via the engineering menu's?

[daz]

Hi prodave
Copying eeproms is pretty easy, there was a circuit for one in the old TV mag, which works great, if you’ve got a copy and costs pennies to make.
However from the model number this is only a 15 inch TV, may I suggest life is too short, add it to your pile of scrap TVs head off down the pub
 
It’s been a bad week! (All hope is lost)
Daz

[ProDave]

Very true.  As you say it's a c**p tv anyway so not worth spending any more time on.

I've got it as good as I can.  My wife says it's fine, but I can see it's still not right. I wouldn't be happy keeping and using this tv anyway even if the colour was perfect as it's very poor in many other respects.

Look out for it on sale on ebay some time soon.