Looking forward to the future and the demise of PAL.

That's good news that you have a fall back plan. Are the photos any better if you turn off the flash, well it looks like the flash is on?

Frank

Hi Frank,

               the flash is switched off. To take a reasonable picture the contrast and brightness controls have to be turned down to display a very dim picture.   These are bit touchy in this 2028, but what do you expect the set will be soon fifty years old?   This is the set that was hard wired to 625 only, plans are afoot to return the set back to dual standard operation.

Till Eulenspiegel.

Certainly more promising results than with my converter which, as with prior experience, neither works with my laptop or the WD TV boxes.

Cathovisor said
Certainly more promising results than with my converter which, as with prior experience, neither works with my laptop or the WD TV boxes.  

Hi Catho,

Just a thought.....when used on my laptop an external power supply is needed for the converter to work however when used with the DVD player no external power is required, did you use an external power supply with your converter ?

Marc.

marc said

Hi Catho,

Just a thought.....when used on my laptop an external power supply is needed for the converter to work however when used with the DVD player no external power is required, did you use an external power supply with your converter ?

Marc.  

Yes.

It's over a week ago since I received the HDMI to PAL converter and I can report it continues to deliver excellent results.  So the next stage of the experiment is to connect the 625PAL output to an Aurora SCRF405 standards converter.

I'm considering buffering the analogue outputs through emitter followers in order to reduce the loading of the chips in the HDMI unit.  A good idea?

Till Eulenspiegel.

Till Eulenspiegel said
I'm considering buffering the analogue outputs through emitter followers in order to reduce the loading of the chips in the HDMI unit.  A good idea?

Buffering may not be necessary as the unit has "RCA pins jacks" suitable for coax cable. That implies the output is 75 ohms, and intended to drive a 75 ohm terminated load.

You can do a simple experiment to verify this if you have an oscilloscope. Connecting a 75 load resistor will reduce the signal(s) by 50% only if the source is also 75 ohms. Even if it doesn't drop by exactly 50% it will reveal something useful about the driving circuits in the unit. This test will not harm the circuit(s).

Given the origin and questionable build quality expecting a "correct output impedance" may be a long shot.

Interested in your results!

Well, the apparent absence of an output on my HDMI converter might be due to my TV actually having a sneaky fault on it - no coded video inputs seem to work. Of course, because the video recorder and set top box feed the set in RGB, I'd not noticed the lack of coded signals and something must be working to allow the sync sep to work... wonder if it's the big chip (TDA 3505 IIRC)? 

If anyone has a circuit diagram for a Panasonic TX24A1, it'd be helpful - what I've found on teh Interwebz doesn't match my set! I do have the manual - it's just finding it... 

Cathovisor said
my TV actually having a sneaky fault on it - no coded video inputs seem to work. 

What I have noticed on aging equipment, particularly TV/Monitors with NTSC and PAL decoders, is a refusal to decode composite video leaving only a B/W picture.

The problem appears to be drift or aging in the local subcarrier oscillator crystal(s), and a light touch of the trimmer capacitor does the trick.

Like you I went in search of the circuit diagram and dug it to what I thought might be a problem with the burst flag. The 1990s vintage multi-standard sets I have are a nest of discrete analog and logic built around large decoder chips.

Good luck!

FordAnglia said

Cathovisor said
my TV actually having a sneaky fault on it - no coded video inputs seem to work. 

What I have noticed on aging equipment, particularly TV/Monitors with NTSC and PAL decoders, is a refusal to decode composite video leaving only a B/W picture.

The problem appears to be drift or aging in the local subcarrier oscillator crystal(s), and a light touch of the trimmer capacitor does the trick.

Like you I went in search of the circuit diagram and dug it to what I thought might be a problem with the burst flag. The 1990s vintage multi-standard sets I have are a nest of discrete analog and logic built around large decoder chips.

Good luck! 

Errr, no, it's more than that - there is no video whatsoever. Somewhere/somehow it it separating the syncs out, but there is no picture content at all.

Catho your set uses the Alpha 2W chassis, Check around the TVSM1326P TV/AV switching chip
IC2601 with a scope.

Panasonic sets around this age suffered from the small 10nF caps going leaky in almost any position in the set (usually reading around the lowish k ohm range), so much so that it was a good idea to check these first in any faulty stage.

 The afore mentioned TVSM1326P TV/AV switching chip (IC2601) of course is under control of the sets  main microprocessor IC 1203 (MAB XXXX), there are two micros used on some models another MAB XXXXX series on the teletext panel which can also affect the video/synch path when faulty, not forgetting of course the CITAC chip type SAB3035 (IC 171) which can also be responsible for various problems as this is the Computer Interface for Tuning and Analogue Control, and is also under control from the main micro via an I2C bus.

EEPROMS (IC1202) can also cause weird and wonderful symptoms when corrupted.

There are huge differences in features between the various models within the basic Alpha 2 chassis group, as some have Nicam etc..etc  the AV switching  and main micro is obviously very different to cater for this, there are still further differences between models even within the same sub-chassis groupings (Alpha 2W in your case), although the Alpha 2W designation mainly identifies it as the large screen (110 degree tube) variant of the base chassis number, and does not reflect on any particular feature that may, or may not be present within that particular chassis variant.

Well, I found out what the problem was, and I didn't even have to break the 'scope out: it came to me during my lunch break at work yesterday and I've just proved it.

It's the Manhattan HD STB - in RGB mode it seems to permanently assert the 'Fast Blanking' signal to the SCART (pin 16), even when in standby. Switch the box to provide a composite output and the problem goes away.

Now, either I swap it for the Humax upstairs or I feel a mod coming on tied to the standby LED.

Hi Mike,

Do the mod, you know it's the only logical thing to do! Plus of course, it'll be more interesting....

Got a problem with a Samsung LCD TV which was made late 2007.  The set will not accept signals from an Amazon Firestick though the HDMI inputs.  OK other devices. It's possible the set can not handle latest versions of HDMI.

Quick fix!   Use an HDMI converter.  Tried this trick this evening and it works, the converted to PAL signals are connected to the phono sockets designated as "AV"  Picture quality is excellent.

Till Eulenspiegel.

Katie_Bush said
Hi Mike,

Do the mod, you know it's the only logical thing to do! Plus of course, it'll be more interesting....  

Actually... I wonder if a quick e-mail to Manhattan to see if this can be addressed in the STB's software might be the way to go?

E-mail sent to Manhattan. Let's see what happens...

It was one of these converters like in the first post I used a couple of years ago to put an HDMI socket--On a Bush TV62!

Works well....