Generic Modulator Help
 

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

Re: Generic Modulator Help
 

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.

Re: Generic Modulator Help
 

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

Re: Generic Modulator Help
 

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.

Re: Generic Modulator Help
 

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

Re: Generic Modulator Help
 

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.

Re: Generic Modulator Help
 

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

Re: Generic Modulator Help
 

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.

Re: Generic Modulator Help
 

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

Patrick

Re: Generic Modulator Help
 

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...

Re: Generic Modulator Help
 

Hello Patrick,

Try here:

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

Regards,

Dave.

Re: Generic Modulator Help
 

Thanks for your replies and help folks....

Re: Generic Modulator Help
 

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

Re: Generic Modulator Help
 

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

Re: Generic Modulator Help
 

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

Re: Generic Modulator Help
 

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...��