Tevion LCD32091D Test Patterns???

[notallbad]

Tevion (Medion)

Turn the Tv on and all functions appear to work, keyboard panel vol up and down, channel up and down, source, menu but the screen looks like its in test patterns, audio works when a source is connected.
When Menu is selected a box appears without text but looks like it would be the Menu box.
Select vol up and down and what appears to be the volume bar appears except theres no volume number just a blank oblong box.
Select Source and a box in the top left corner appears except theres no text but a bar appears that scrolls up and down and source can be selected and changed.

The screen looks like test patterns but I think the issue is either with the T-con or possibly SSB i.e Scaler
PS board: MLT666 Rev 2.8 all voltages ok
Main A/V board: TV3201-ZC01-02

[tom66]

Re: Tevion LCD32091D Test Patterns???

My guess corrupt EEPROM or perhaps bad RAM, both on main board.

[notallbad]

Re: Tevion LCD32091D Test Patterns???

There are 3 Atmel eeproms

24c02
24c04
24c32

What are each of these for?

I have replaced the 24c32 which I assume is for user settings but no change.
I have a 24c02 so could have a go changing that one.

Shall get a photo of the board and post it.

[tom66]

Re: Tevion LCD32091D Test Patterns???

I don't have the slightest clue. The differening digits at the end are the size in kilobits (1 kilobit = 1/8 kilobyte)

[notallbad]

Re: Tevion LCD32091D Test Patterns???

Main A/V board

U2 - 24C02
U4 - 24C04
U10 - 24C32

[notallbad]

Re: Tevion LCD32091D Test Patterns???

U14 - 1117 0395 ADC

Pin 1 - 4.98v
Pin 2 - 0.93v
Pin 3 - 0.048v
Tab - 0.93v

Could someone tell me if this sounds correct, there are a couple of resistors on pin 3.

[budm]

Re: Tevion LCD32091D Test Patterns???

Just to be sure that the pin you call pin 1 is the pin to the right looking at the IC with the big tab up?
The output should be about 1.25V.
The correct pin number is (big tab up) left is pin 1 (Ground for fixed regulator or Adjust for the adjustable regulator), middle is pin 2 (output, it is tied internally to the big tab), right pin is pin 3 (input)

[retiredcaps]

Re: Tevion LCD32091D Test Patterns???

U14 - 1117 0395 ADC

Pin 1 - 4.98v
Pin 2 - 0.93v
Pin 3 - 0.048v
Tab - 0.93v

Could someone tell me if this sounds correct, there are a couple of resistors on pin 3.

U14 is bad. See the how to test a voltage regulator FAQ as to why.

[notallbad]

Re: Tevion LCD32091D Test Patterns???

Thanks.
Yes pins correctly identified.

Looking across the board I have found another 1117 - U30 with the following
Pin 1 0.4v
Pin 2 and tab 0.65v
Pin 3 0.7v

Definately suspect, and requires further investigation.

[tom66]

Re: Tevion LCD32091D Test Patterns???

Its input voltage is not high enough so it's probably OK for now. But see if you can locate where it is being powered from since when the set is on all regulators will usually have power. If it is in standby those readings may be fine.

[notallbad]

Re: Tevion LCD32091D Test Patterns???

Correction for post #6, I did in fact read the pins backwards

U14 - 1117 0395 ADC

Pin 1 - 0.048v
Pin 2 - 0.93v
Pin 3 - 4.98v
Tab - 0.93v

So input is ok but the output is reading too low, as this is an adjustable reg could it be that theres nothing wrong with the reg but in fact due to a fault on the adj gnd causing the output to be pulled down so low?

[tom66]

Re: Tevion LCD32091D Test Patterns???

Is the regulator very hot when you touch it? Or is it cool to the touch?

[notallbad]

Re: Tevion LCD32091D Test Patterns???

Very cool as if its not doing anything, the TV is on and not in standby.

There are a couple of larger regs on the board that when you touch it, 1 2 secs ouch thats long enough!

[budm]

Re: Tevion LCD32091D Test Patterns???

It is an adj type regulator, if the ADJ pin is grounded directly or through resistor network it will not cause the output to be less than the ref. voltage of 1.25V. Minimum output will always be 1.25V.
So it may be bad reg, so check to see if it is running hot as Tom suggested, or it is heavily loaded, or bad filter cap at the output.
I think it may be just bad regulator.

[notallbad]

Re: Tevion LCD32091D Test Patterns???

Not having much luck finding any spare adj regs on the spare boards (plenty of fixed 1.8v and 3.3v) I have and the cost of them for one on fleabay looks extortionate!

[tom66]

Re: Tevion LCD32091D Test Patterns???

Too much?
http://www.ebay.co.uk/itm/2-x-SMD-SM...item3efd077ad1

[notallbad]

Re: Tevion LCD32091D Test Patterns???

Well, I saw some much dearer just for one so perhaps I shall buy buy buy!
Thanks Tom

[notallbad]

Re: Tevion LCD32091D Test Patterns???

Found a couple of bad caps on the PS b/d so replaced them, then found an adj reg on an old PC motherboard, now switches on and displays an image.
I shall bench test to see if any issues arise. One thing I did notice after having my laptop connected to the VGA port is that the 'source' and 'menu' and 'volume' boxes displayed as before but this time the tv still showed the display image. I quickly switched it off in case its the pc input thats the cause of the fault so shall run it through all the other inputs first then try the pc input again later once I'm happy everything else is working.

[budm]

Re: Tevion LCD32091D Test Patterns???

Glad to hear that it is working.