[zxspectrum] Re: QL con problema
- From: Massimo Raffaele <massimo.raffaele@xxxxxxxxx>
- To: zxspectrum@xxxxxxxxxxxxx
- Date: Mon, 2 Jun 2014 16:13:19 +0200
Hi Rich,
I can see from the photos that this QL is suffering from 'screen flare'.
> This is normally down to the MC1377P chip, but can also be the 8301 and/or
> 8302 ULA causing interference.
> It can also be a problem with the TV modulator itself.
>
Hmmm, a premise: I fear I would get the same problem if connecting the QL
via composite signal... because the VCR I have (with the same defect) is
connected via composite and not RF.
That said, you could be right.
> I would recommend that in the first instance, you remove the 8301 chips
> from their sockets and push them back in (as it can be carbon build up on
> the pins).
>
Damn, so I'll have to open it, risking my poor old membrane...
Ok, if necessary I'll do it.
> I have in the past tried to do a composite video modification to the TV
> modulator on the QL, but this does not work due to interference. There is
> a much simpler solution however, which is to make up a composite video lead
> which takes the video signal from the RGB connector to give a stable supply
> (use PIN 1 Composite PAL and PIN 2 GND on the RGB socket) -
> http://www.fruitcake.plus.com/Sinclair/Spectrum128/SCARTCable/Spectrum128SCARTCableQL.htm
>
Wow, thanks for the new fruitcake website link! I had the old one and it's
not complete anymore.
Yes, one of the ideas which came to my mind was to try buying a RGB cable
from eBay (I know a pair of guys are selling true RGB cables for the QL,
for 13..15 euros).
I could indeed build myself a composite SCART cable, as you suggest, but:
1) I would prefer a RGB signal, which is cleaner
2) if the problem is due to some bad component influencing both the
composite and the RF signals, but _not_ the RGB output, I could bypass the
issue using a RGB cable.
What do you think?
Max
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