Can't get a display output with my ZX Spetrum 128k+2 (Grey) model

[EranStockdale]

Hey there!

I've just been given a ZX Spetrum 128k +2 (Grey) model by a friend. I know for a fact that it works with RF output as the friend showed me it working before he gave it to me, but I can't get RGB scart working. I'm using the adapter from coolnovelties (https://www.amazon.co.uk/dp/B01477XBZM). My TV detects that it's being plugged in but says there's no video output. How can I debug this and what are some potential fixes?

[1024MAK]

Hello and welcome.

Two things, the correct RGB/SCART cable has to be used. It has to be the type specifically for the grey +2. You have linked to a different cable.

The ZX Spectrum was designed before most TVs had automatic SCART function switching. A TV that has automatic SCART function switching often won't work correctly, as it does not recognise that there is a RGB signal and only looks for a composite video signal. Not much use when there isn't a composite video signal...

It's possible to overcome this problem, but it does require modifying the cable. To do this you need to be able to solder.

Mark

[EranStockdale]

Hello Mark,

Thank you for your response! Do you happen to know where I can get the correct cable? Also I can solder and have my own kit.

[1024MAK]

Here's eBay links to two sellers I have used before:

Retro Computer Shack - Sinclair ZX Spectrum+ 128K & +2 (Grey Model) RGB Scart Lead Video Cable TV Lead
https://www.ebay.co.uk/itm/260949446667

Website https://www.retrocomputershack.com/


CoolNovelties - SINCLAIR SPECTRUM 128k +2 (GREY MODEL) RGB SCART LEAD
https://www.ebay.co.uk/itm/390288649031

Website https://coolnovelties.co.uk/coolnovelti ... 06296.html


Ian, of Retro Computer Shack also shows the technical details of his cable here.


Once you have a lead with the correct wiring, if you are still having problems, if the TV has more than one SCART socket, try each SCART socket. See if the TV has user/menu settings to select RGB mode and 4:3 aspect. Try another TV.

Note also that the ZX Spectrum +2 internally has option links that are set depending on which country it was intended to be sold in. The cables sold in the UK are for the UK model. If you carefully open the cover (treat the keyboard membrane tails gently) you can check the links. See here for the technical details.

If none of this helps, please post here again detailing what you have done / tried so far.

Mark

[EranStockdale]

Brilliant, thank you! I will get back to you after I have acquired the cable and let you know if it works.

Although, I do have another question for now: the TV I am using has an RF input port but when I try to find the spectrum's signal it fails, how can I diagnose why? Also, what frequencies does the spectrum usually run at? The TV starts auto tuning from around ~400MHz, but that is near the frequency my friend got it working at, so maybe it's going too high?

[1024MAK]

The modulators in all UK ZX Spectrums officially use channel 36, that's 591.25MHz. However, as the modulators are purely analogue devices, the actual frequency can be anywhere between channel 35 and channel 37 (583.25 to 599.25MHz).

Auto tuning normally fails, as the chances of the modulator actually being on the exact specified frequency is extremely low. So, if your TV has manual and/or fine tuning, use this.

Mark

[EranStockdale]

Cool, thank you. I'll give that a go in a bit (I need to find the remote so I can use numbers to type the frequency haha, it's been years since I've used this TV!

Eran

[EranStockdale]

Okay so I've gotten to the manual tuning settings, but there are some default things that I don't know if I need to change or not. I've listed them below, what should they be?

Sound System: DK
Colour System: SECAM
AFT: Off

[1024MAK]

Sound system is I (I for India, system I is the UK TV standard)
Colour System is PAL or PAL 50
AFT OFF

Mark

[EranStockdale]

Thanks! I've given manual/fine tuning a go and it refuses to work. Is it possible to manually modify the cable I already have to get it to work? I only ask as the sellers you linked are away until January

Eran