Sinclair ZX80 / ZX81 / Z88 Forums

So having finally persuaded someone in the USA to send me a TS1500 how do I go about composite modding it so I can actually get a picture out of it?

I think I have plenty of reading to do in the meantime...


Many thanks!

The signal can be adapted usually from the modulator. You can find 5V here as well as operating voltage for the modulator and can find ground in the near somewhere on the board.

Thanks Pokemon.

If anyone knows where to pick up from this lot I would be very grateful! Having never seen one of these before today and paid handsomely to get it from America I am reluctant to break it!

Here is inside the 'modulator'...
I think this may be an earlier one (s/n 5509) and the later ones had the full on 'normal' modulator in them?

Lardo Boffin wrote: ↑Fri Aug 25, 2017 1:02 pmHere is inside the 'modulator'...

IMG_6732.JPG

I think this may be an earlier one (s/n 5509) and the later ones had the full on 'normal' modulator in them?

Don't know, but as they were made for the American market, it does not surprise me that the modulator circuitry is on the main PCB with a screening can plonked on top.

As to the video, +5V and ground, well, using a multimeter on the 200 ohm range should soon find a suitable pad to pickup the +5V. Put the red meter probe on the +5V output pin of the 7805 voltage regulator. Then search with the black probe at likely looking tracks until the meter says zero ohms (0 to 0.3 ohms).

For 0V/GND, you can use a similar technique or just solder to the screening can.

For the video signal, I strongly recommend that a buffer transistor is used, or use one of PokeMon's Z8-CCB modules. The equivalent of the ULA is the square surface mounted chip. The video comes out on one of it's pins and goes to the modulator via some passive components (a resistor divider I think). Details are on the TS1500 schematic. I suggest picking it up at the resistor divider. Finding it on the board may be slightly tricky.

Mark

Thanks Mark.

There is a photo of a later model here that has been ZX-VID'd by Mutant Caterpillar Games

https://highpriestessofspectrum.wordpre ... rousel-754

It looks like the video feed has been taken from a resistor (possibly) closely connected to the ULA but it's hard to tell which one.

As an aside given that these have 16k of internal RAM do they need the capacitors replacing?

Also would the regulator be replaced in the same way as a normal zeddy?

Questions, questions!

It turns out that RF works just about on one of my TVs!

The output is a bit jittery and occasionally shows some colour but is legible!

Nice.

I finally decided to get it ZXVid’d. Truth be told I didn’t want to risk killing it given how hard they are to come by.

Very nice picture!


I know - I will plug in the ‘spand and see how wonderful the high res games look!

It seems I have a slight ‘spand related issue...


I guess I will need an edge extender (or two) as the board completely covers the TV out!

A single extender board and this will help:

https://www.ebay.com/itm/2X-RCA-Male-to ... Sw8-tWVzOW

Siggi

Also some way of reconfiguring the RAM. The TS1500 has 16k internal, which remaps when a ram pack is plugged in. This will conflict.

C