Generic Modulator Help

[patrickgnl]

I have a generic rf modulator, that is now stuck in ‘test card’ mode. Ie black screen with two vertical white lines, like you'd find on a VCR.

See pics below, the modulator is capable of PAL/SECAM B/G/H/I/D/K and NTSC M, to select - you press the channel +/- button together on the base and cycle between the sound carriers ie 4.5, 5.5, 6.0 and 6.5. You then switch it on and off to commit the setting. That bit i get..

I have tried every possible key press including powering on with buttons pressed etc but it resolutely refuses to show a picture and remains stuck on the test card.

The polish instructions say the same as the English (according to google translate), neither mention the testcard. Any ideas?

Many thanks



Patrick

[rambo1152]

These things are sometimes sold under the brand name "Simply Digital".

Have you tried a different video source? I'm just wondering if it defaults to a "tuning signal" if it doesn't detect a valid input.

Unlikely, but it's the best I can think of.

[patrickgnl]

Thanks for the reply Graham, that was an excellent idea, but sadly it didn't work.

I have tried two different freeview boxes, it passes the audio along with a tone and the white striped image. I *have* had it working, but obviously while messing pressed a key sequence in error. duh...

Judging by the number of views and just your (very helpful) comment, it will be destined for The recycling... oh well

Many thanks again.


Patrick

[dragonser]

Hi,
well it would be a shame to recycle it, as at least it would make a multistandard pattern generator !
I wonder if the similar modulators use the same digital ic's and if there would be a clue in the data sheets ?
I have a dragonsat modulator that can do different standards.. but no instructions with it.. luckily pressing both buttons does the same as on your modulator.

[patrickgnl]

Now theres an idea - although i dont have the knowledge to understand the datasheets.. i am hoping you can help?

Two ICs

1. Elan EM78P153SPJ - 14 pin
2. Atmel 72124C02 - 8 pin

I found the first datasheet, but a bit (read - way) above my skillset. The second seems illusive. Pics of inside attached, it may well be identical to the dragonsat.

Thanks


Patrick

[TonyDuell]

The number to search for on the Atmel part is '24C02'. I am pretty sure it's some kind of E2PROM thing. Is the other IC a microcontroller? THe modulator can itself seems to have an I2C bus going into it (SCL and SDA pins) so presumably that's a bit more complicated than some.

[patrickgnl]

Here is the atmel datasheet... I can’t find a way to download the elan chip datasheet... although it does appear viewable online.

[Dave Moll]

If the problem has occurred as a result of erroneous settings, is there a reset function to return it to "factory settings"? Often these are in the form of a small hole into which a narrow tool (e.g. a cocktail stick) needs to be inserted. I must admit that I don't see a candidate in your images.

[patrickgnl]

Originally Posted by Dave Moll

If the problem has occurred as a result of erroneous settings, is there a reset function to return it to "factory settings"? Often these are in the form of a small hole into which a narrow tool (e.g. a cocktail stick) needs to be inserted. I must admit that I don't see a candidate in your images.

I had already checked, it was my first thought, i couldnt see one....

Patrick

[dragonser]

Hi,
the ic I was wondering about was the Ic used to generate the sound and vision rf signals, which would be in the metal case...
if it uses the MC44cc373 ic ( it may not do ) , there is also a Sony ic CXA1929m that might do the similar thing... then the datasheet for the MC44cc373 says there is a test mode.. two white vertical bars and a 1 khz tone...
these ic's are controlled by an i2c bus which would be provided by the ic's you have taken a picture of...
This means that there is no easy way of knowing ( as far as I can tell ) what buttons need to be pressed to switch out of the test pattern mode...

[Amraduk]

Hello Patrick,

Try here:

https://www.datasheetq.com/datasheet...AN/EM78P153SPJ

Originally Posted by patrickgnl

I can’t find a way to download the elan chip datasheet... although it does appear viewable online.

Regards,

Dave.

[patrickgnl]

Thanks for your replies and help folks....

[Andy Doz]

Looks very similar to the CCT811... make sure you fit a fuse somewhere...

I wrote about it here ..

https://andydoz.blogspot.com/2016/02...epair-and.html

and

https://andydoz.blogspot.com/2016/07...e-failure.html

[patrickgnl]

Thanks for the links, youre right its exactly the same. It is fused at plug, i am always dubious of cheap chinese stuff and tend to unplug it when i am not using it anyway.

So i now not only have a device stuck in test screen mode, but an electrically unsafe one at that. Recycling here it goes...

I wonder how many folk die of electrocution/electrical fires in china? So much of their generic unbranded stuff is so dodgy, it does make you wonder..

Thanks again.


Patrick

[Heatercathodeshort]

It's only a small item to store. As soon as you dump it you will discover a cure! John.

[patrickgnl]

Actually that is what i have done, ive put it back in its packaging and written on it the issues, then put it with all of my other shizzle...��