The Sinclair QL Forum

Hmm... Looking for suggestions as to what I can try at arms length with a customer....

Customer has 2 QLs which he has been using for a while. He has RGB cables to a colour monitor, a monochrome monitor and a TV...

He has come to use his QLs and got a blank screen on all 3 output devices. I thought it might be possible that a faulty monitor had taken out the MC1377P chip on both QLs, so he sent them to me for testing (without the psus).

Both machines work fine here with both my QL Vision and Microvetic Cub monitors (using my cables as his RGB cable does not fit for some reason)...

On a TV, the one works, but with noise on the screen from the connected Sandy SuperQBoard. Without the SuperQBoard, there is no interference.

The other QL shows the typical glare and poor colour you often see on some QLs. I changed both the 8301 and MC1377P on that QL, but there was no improvement in the TV output. so it is probable that the TV modulator (which looks rusty) is faulty.

However, apart from returning his QLs with a spare PSU (to borrow) for him to test - what else could I recommend the customer?

How experienced is your customer?

"Blank screen" - really need a bit more info. Blank as in no signal at all? Or blank as in a black screen?

What connections are being used for the monochrome monitor and the TV?

Does the customer have any other video sources to test his displays with? For example, if a SCART connector is being used, test with a DVD player that has a SCART RGB mode.

It is somewhat perplexing and confusing that three displays and two computers all result in a blank screen

Mark

I agree it is perplexing....

So far as I am aware, he just sees no output at all....

The monitors are connected via the RGB socket on the QL - the TV via the TV modulator - he has sent me his cables, but the RGB connector looks odd - it is not one for a standard microvetic, as both ends are exactly the same (ie the QL connector) - so it does not fit my microvetic.

I guess the lead to the monochrome monitor is attached to the monitor - alas it will have a QL RGB connector on the end, so not much else that could be connected to check the monitor / leads at his end - he may take this to a TV repair shop for testing.

I think the problem may lie in his power supply - as he has tried 2 PSUs, it could well be the extension cable he is using ( a multi-strip) - although the QLs seem to work plugged in, the lack of display could indicate that the 12V line is not working properly ...

Is the customer actually using the RGB output, or just the analogue video output?

Is it something really silly like there is a switch on the monitor, that has been moved from RGB to something else. Or for the aerial input, it's just off tune?

Customer issue resolved by using a TV - he needed to retune his TV channel for the QL.

The monochrome monitor still gives no output.

The RGB (Phillips) monitor shows a flickering display - he thinks this maybe the horizontal or vertical hold, so is going to see if there are any settings to adjust.