The Sinclair QL Forum

Martin_Head wrote: Tue May 06, 2025 10:55 am You might also want to check that the +12 volt line is there. I think it's pin 14 of the MC1377.

I can't quite remember that if the 12 volt is missing, You get no composite video, or no colour.

The 1377 (and, thus 12Volts) is not needed for RGB. Only for RF and composite. So, it depends on what the OP's HDMI converter wants to be fed with.

Yes, you can pull the mc1377p and still have fully working RGB.

I'm actually wondering if anyone on the forum would be close by and be able to help rather than just keep buying random adaptors etc.

Hi, thanks again to all your replies. I will try to answer where I can. First though, here is the Picture of the QL insides as requested (hope this works lol)...


https://www.dropbox.com/scl/fi/ei7cgxa5 ... 024pg&dl=0

Has the QL ever worked with this converter and cable?

- No, I have only ever had it working through an RF ariel lead to my old TV in the 80's

Not many modern TVs has not RF signal. That is a very good reason why nowadays I don't recommend Vid.comp mod, because almost every modern TV has RF signal input. Only very few has not. So I guess yours (by your reply) is one of those.

- My current TV does have an RF input on it, so are you saying I can just run the QL RF out to this TV and it will tune in to it? Sorry if its a dum question, but I am no expert in electrics and am struggling with some of the terminology...

Some TV's retain an analogue tuner, but tuning it is a PITA also getting a good quality picture is even harder. However I would look into that as it will show 'proof of life'. Personally I think the cheapest option on the market for a good picture to a monitor is the picoVGA. I knocked one up using some bits I had kicking around. it wasn't pretty, but the output was fantastic. I generally use an RGB2HDMI which also gives fantastic output. These aren't the only options available. I wonder if you would post a picture of the converters you have?

Sme007 wrote: Tue May 06, 2025 6:06 pm

Not many modern TVs has not RF signal. That is a very good reason why nowadays I don't recommend Vid.comp mod, because almost every modern TV has RF signal input. Only very few has not. So I guess yours (by your reply) is one of those.

- My current TV does have an RF input on it, so are you saying I can just run the QL RF out to this TV and it will tune in to it? Sorry if its a dum question, but I am no expert in electrics and am struggling with some of the terminology...

Yes, I am saying exactly that. You can connect your QL to this TV RF signal.
You can use for example a ZX Spectrum RF/TV cable, they are the same, or if you have the QL RF cable, that is fine too.
Then tune in the channel 36 (if I am not wrong), that is UHF band. And that's it. you will get the image (if the system RF is not damaged.

There are 2 options if the QL actually works:
1. You get "something" but not a QL image (the freq is close to but need to fine tune) or something inside QL is damaged (what we want to try out). Do not forget to try fine tune if you think almost got something. It is due to some TV autoscan system get stopped just few freqs before the central band. Not often, but sometimes happen. So just imagine you want to tune your favorite channel searching on it.

2.You get image of your QL, congrats. half of the way done. And then we should focus on RGB output & your RGB2Scart or RGB2HDMI converter or cable.

In any case... please do not use any RGB cable by now. I insist very much on it. Use only RF cable (RF Output/TV modulator).

if not image at all, please to do the rest of basis tests described and report the results. Also try to detail (if as you said you have not electronic acknowledge) how did you try to tune the QL on your TV.
I'm supposing you have not any electronic skill and you are not sure how to deal with a TV to tune a program.

Now we don't care about the quality, but to know if it works or not.

Now you show your board (an ISS5) so it is easier after basis tests (that I wrote in my first post to you) to guide you better to find the problem.

Hi, WOW, WOW and WOW. I did what you said, and connected it to my big TV on the wall using just a QL RF out to the Tele RF input. There was no manual retune option, so I chose auto tune and after about a minute of searching it said one channel found and the QL screen appeared. The picture is a bit fuzzy, but perfectly readable and there is a low buz sound, but nothing to worry about there. I am well happy, thank you all so much you have all been brilliant.

My next quest is to refelt all 29 of my microdrives and check if they still have any readable data on them. If they do, I plan to back them all up some how so I don't lose it. I have been looking at purchasing the "vDrive QL - fully assembled with cable £73.00" once I got the QL working, anyone have any thoughts or tips on other options?

https://www.vretrodesign.com/products/v ... with-cable

Thank you all again

Kind Regards
Sme007

Sme007 wrote: Wed May 07, 2025 11:12 am Hi, WOW, WOW and WOW. I did what you said, and connected it to my big TV on the wall using just a QL RF out to the Tele RF input. There was no manual retune option, so I chose auto tune and after about a minute of searching it said one channel found and the QL screen appeared. The picture is a bit fuzzy, but perfectly readable and there is a low buz sound, but nothing to worry about there. I am well happy, thank you all so much you have all been brilliant.

I am very happy you got it.
So after it is working by RF my advice... DO NOT USE THIS RGB Cable. You don't know if inside is broken and could be in bridge or short. So it would damage your QL ULA ZX8301. You would need to test the cable with a tester before to use it. Another point is how this interface to HDMI works, not everyone works the same. Some works passively other actively (like 3D Glasses). So some (again) could work, others not (in short story).

The sound is normal, it is due to freq central band of the final video signal is a little displaced to the audio signal and need to be readjusted (you have a internal var-cap in your QL for that matter, but better to do not touch it). So it is about signals that are not worthy to touch. Also may be (if I am not wrong) because the video signal doesn't contain the sound, QL has a speaker like ZX48K so perhaps the sound is not in the video signal mixed. The best option for a high quality is to use the convertor from RGB to VGA. There is a nice openhardware project with a amazing quality that I advice to you. You can built it by yourself but since you told that you are lack of electronic skills (so I guess soldering too) could be more convenient to buy it to someone who has one to spare. Just be sure the person is a trustful one who knows how to do the cable (I have seen many with the connector badly soldered & isolated that makes with time shorts between pins, what may result in damage to your QL badly).
If you dare to make it by yourself (my recomendation is to try it)... here is the link to the project: https://github.com/holmatic/video_if_ql_vga
It is the one that I use... and WAW! beautiful, cheap & good.

But also and the most important... you need to know why your RGB output doesn't work with those cables & devices. But do not use them to test anymore (at least till do some previous checks).

Sme007 wrote: Wed May 07, 2025 11:12 am My next quest is to refelt all 29 of my microdrives and check if they still have any readable data on them. If they do, I plan to back them all up some how so I don't lose it. I have been looking at purchasing the "vDrive QL - fully assembled with cable £73.00" once I got the QL working, anyone have any thoughts or tips on other options?

https://www.vretrodesign.com/products/v ... with-cable

About refelt... I cannot help. Still I have mine without working at all. I am not skilled at handworks. But I know some people here are very very good at it.
vDrive is a great external solution (IMO). You have also other options like Oqtadrive (a midway (internal and external versions)), ROM-SD or QL-SD or something like this (I like its power) and MicroDrivePico, for internal replacements.
For external... vDrive and QIMSI (between vDrive and QIMSI, personally ... I would get QIMSI). QIMSI is a cartridge format that need to be connected to the ROM port and If I am not wrong requires to remove internal ROMs.
You would need to read every spec of each project or ask. Because all depends of you preference or feelings.

I have used Oqtadrive but it was too complicate for me. In any case have some amazing features (bluetooth, or Wifi) so the author could even power it up a lot with some changes. It is OpenHardware project.
and I'm using also MicroDrivePico (which I feel very comfortable for my expectations and needs).

There are some other projects (external replacements) but I cannot recall all the names.
I hope now you could get better oriented.

I forgot to tell...
Usually the QL that are stored by decades (your case too), get their membranes broken.
Before even to try to buy a Microdrive alternative... I would recommend you to check out your keyboard.
Pay attemption on the membrane connection to the QL Board, the membrane plastic part usually get scratched, broken, teared... what results in non usable keyboad/membrane.
If so... you will need to buy a new one.
RWAP is the shop where I have bought my last 2, and the price, service and quality are amazing. Moreover how they package them in order to arrive in good conditions to you.
SellMyRetro is a site where you can buy those items.

There are other options but in this case (talking about membranes) I'd buy it only by a well known site and seller.
Cheers

Once you have verified your QL is perfectly able to generate an RF signal, you can safely assume its video circuitry is completely OK (RF and composite are internally derived from the very same RGB signals that are on the RGB output). To make sure it stays that way, please follow Popopo's advice.

So, the problem seems to be either with your cabling between the QL and your HDMI converter or the converter itself. Can you provide a picture of what you use? Maybe someone can identify as "works" or doesn't work" on the QL. Properly working HDMI converters (not just for the QL) can be hard to find, and the ones that work might not necessarily cope easily with the QL's non-standard video signals.

The easiest step forward would be when you had something that wants a SCART input - QL-to-Scart cables are relatively easily obtainable and most TVs/monitors are able to display at least something from them.

I'm using three like in the attached picture (obtained years ago from eBay) and they work perfectly well for me. I have alsobuilt a QLVGA, which really is very good (if not better than commercial converters) considering the cost.

Or you go the QLVGA way as recommended above (and maybe find someone who is willing to build one for you, it is really easy, straighforward and likely the cheapest working way to achieve proper video on modern displays).

(There seems to be an offering on ebay UK that is close to my setup, and that I consider way overpriced. I think my converters that look the same were <20€ back in the day from China)