Building a Philips PM5530 sync generator equivalent

[Vincent]

Finally found something interesting as a first project outside the sub-field of repair.

Some time ago I found a PDF scan of the Philips PM5530 sync generator service manual. After much reading to get an idea on how the device works, the document seems to provide enough information to build the generator from scratch! I don't exactly expect this to be a breeze though. The original design uses copious amounts of germanium goodies, with silicon parts mixed in. A number of so-called "circuit blocks" were also used, which in themselves are going to represent a challenge as I can only find internal schematics sans values (but they do provide data on the input and output signals). They're basically a mix of analog and DTL circuits.

I'm fully aware that the functions of this rackmount dinosaur could all fit within a minuscule FPGA nowadays, though my goal with this project is to substitute the ancient semiconductors with modern, inexpensive parts and tweak the passives around them to make the whole thing work. A sort of electronics (re)design challenge, if you will.  And most importantly, an opportunity to gain deeper knowledge. I also plan on documenting the entire process in the form of videos, including the fails. 

Before I truly dive into this madness endeavour, any advice on potential difficulties arising along the way? I don't see huge obstacles ahead but maybe there could be some.

(Just so you know, I do have formal background in electricity, with introductory courses in AC and DC circuit analysis and electronic components, among others. I wouldn't even consider trying this if I didn't at least have enough knowledge to know where to start!)

[schmitt trigger]

To paraphrase Donald Rumsfeld, what gets you are the unknown unknowns….

It would be useful if you shared the PDF schematic, or a link to a website, for us to provide you with more educated guesses.

[Vincent]

Well if you google "Philips PM5530" it's literally the first result, but here it is.

[wasedadoc]

[ Specified attachment is not available ]That is an ancient design with many parts.  Copying it looks feasible but a mammoth project.  Other than as an educational and brain using exercise the finished item would not be particularly useful.  It is not a pattern generator which could be used for testing or aligning TVs.  Its function is to drive TV cameras and other video sources so that they are synchronised to enable mixing and switching without disturbance.

I cannot remember the exact year but sometime between 1976 and 1980 I designed and had assembled a small number of boards with similar Sync Pulse Generator functionality which were used by a UK household name for several years.  Using about 20 standard TTL chips and a transistor or two (the 8 MHz crystal oscillator) it delivered 4 each of the standard monochrome signals. 2 Volts peak to peak into 75 ohms. All timings derived from the crystal to 250ns resolution and within UK broadcast 625 line timing spec. No adjustable components or AOTs.  Composite sync, mixed blanking, line drive and field drive.  Double sided PCB about 250 mm by 125 mm.  It also had a video output (1 Volt peak to peak into 75 ohms) which was a black background and a single line of up to 32 alphanumeric white characters as identifier.  A socketed 74S188 32x8 PROM held the character codes and a Texas Instruments 2501 ROM converted the character codes to the 8x5 matrix of character dots.

I don't have the schematic but I do still have one sample of the board which I powered up and confirmed working about 6 months ago.

[Terry Bites]

We know we don't know the reasons why so many posts come via IT devices with no file system or drawing package and no one with a camera and a chared stick at the other end.
We should assume that the bots have long since taken over this forum. Actually the bots would put up a picture or two.
Talk is cheap.


So analog TV is making a comeback. Finally!

[Vincent]

lol I'm no bot 

I'm just into analog video stuff, because reasons. As illogical/pointless/weird/stupid/whatever as it sounds, this is a legit project.

That is an ancient design with many parts.  Copying it looks feasible but a mammoth project.  Other than as an educational and brain using exercise the finished item would not be particularly useful. 

This is to a large extent what this project is about, indeed! I've got sufficient knowledge to give it a try (hopefully) but I want to get some additional experience in circuit analysis while also creating something I'll enjoy using on other related projects in the future.

It is not a pattern generator which could be used for testing or aligning TVs.  Its function is to drive TV cameras and other video sources so that they are synchronised to enable mixing and switching without disturbance.

In fact the PM5530 does generate a basic cross-hatch pattern. The PM5540 is the actual test pattern generator, which needs sync pulses from a PM5530 to run. But one challenge at a time LOL.