Author Topic: Best 14" CRT for the CPC OR is my CPC 464 scart lead knackered?  (Read 8809 times)

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Offline RetroRevival

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Hi guys, hope all is well.

I come here for some advice and assistance.

I have a Sony Trinitron 14" crt which I use for retro gaming, usually via the RF.  Today I made up a scart lead for my 464 and when I plugged it into the scart on the TV the picture appeared for a second then I was given a black screen with the feintest white writing on it, which it stays on until I turn the CPC off.  I added the capacitor as per the alternative methods in the wiki article but no luck, still the same.  The same lead produces a stable image on my 26" samsung LCD, however there is a lot of shadow in the picture.

Any ideas on how to fix this or failing that what 14" crt to go for?

Thanks in advance
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Offline mr_lou

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The black'n'white image has been up a few times. There can be different reasons. Try searching a bit.

Once I experienced it myself, it turned out to be because the cable I'd made was too long. But cutting it in half, it worked.

I've also tried TV's that gave a poor picture. Generally Phillips gives me good results. But recently I bought a Samsung LCD which is also fine (even though my 14" Phillips CRT gives a more crisp picture of course).
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Offline robcfg

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Maybe your CRT is not detecting voltage on the scart pin that tells it that signal is RGB.


Scart has all three signal (or at least, room for them three), Composite, S-Video and RGB, and usually needs voltage on certain pins to indicate the TV set which signal is available.


Take a look at the various Scart cable diagrams here on the CPC wiki, some contain a battery attached to a pin.
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Offline RetroRevival

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The black'n'white image has been up a few times. There can be different reasons. Try searching a bit.

I did, but all posts I saw mentioned the flicking between colour & b& w which mine is not doing.

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Once I experienced it myself, it turned out to be because the cable I'd made was too long. But cutting it in half, it worked.

Definately something to try, my cable is nearly 2m long, will try a shorter length, thanks for the advice.

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But recently I bought a Samsung LCD which is also fine (even though my 14" Phillips CRT gives a more crisp picture of course).

I get bad shadowing on the my LCD, but on the Sony CRT I get a crisp picture even if only for a second or so.

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Take a look at the various Scart cable diagrams here on the CPC wiki, some contain a battery attached to a pin.

Will try the smaller cable and if not will look into the battery idea.

Again, thanks for the advice.







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Offline RetroRevival

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Reduced the cable length to around 1m and reseated the wires on both the din and scart end, and now I get a rolling colour picture with the 14" Sony CRT (which is RGB apparently) unable to lock onto the signal properly.  I have tried both the 100uf cap on 16 and 18 and have also tried the 1.5V battery trick and still no joy.

My freeview box works fine via RGB on the same scart socket so have ruled out the TV as the problem.  Starting to think that it might be the CPC now that is the problem.
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Offline Bryce

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The capacitor or battery won't stop the rolling unfortunately. The rolling occurs when the TV can't sample the RGB signal at the rate it needs to. Unfortunately, this means that the TV is probably unsuitable for "Retro RGB". Let us know the exact make and model so that others can avoid buying it. What other inputs does it have to offer? And what other CPC Hardware do you have - MP1/2 ?

Bryce.
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Offline RetroRevival

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Hi Bryce,

Its a Sony Trinitron 14T1U CRT, with Scart, RF and front Composite / Audio jacks.  I also have an MP1 which gives a very washed out picture which I have put down to it being plagued with the general MP1/MP2 failures that others seem to have got.
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Offline TFM

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Hi Bryce,

Its a Sony Trinitron 14T1U CRT, with Scart, RF and front Composite / Audio jacks.  I also have an MP1 which gives a very washed out picture which I have put down to it being plagued with the general MP1/MP2 failures that others seem to have got.
Actually, the Sony Trinitron is quite good for the CPC. Maybe there are different models (probably?) or is the monitor itself broken? In any case good luck!
 
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Offline Bryce

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You could try doing the MP1 to Composite conversion here: http://www.cpcwiki.eu/index.php/LCD_And_Plasma_TV_Solution
It's an easy conversion and should give you a better picture when connected to the composite input on th esony.

Bryce.
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Offline RetroRevival

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Actually, the Sony Trinitron is quite good for the CPC.

I purchased it due to the "compatibility" it allegedly has with the older consoles and computers, however I may well have purchased a dud one :(

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You could try doing the MP1 to Composite conversion

I was looking at that and might venture down that road eventually but was hoping to use the scart as I have plenty of other computers that will need to use it too.


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Offline CanonMan

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Re: Best 14" CRT for the CPC OR is my CPC 464 scart lead knackered?
« Reply #10 on: 01:12, 09 September 11 »
Hi Bryce,

Its a Sony Trinitron 14T1U CRT, with Scart, RF and front Composite / Audio jacks.  I also have an MP1 which gives a very washed out picture which I have put down to it being plagued with the general MP1/MP2 failures that others seem to have got.

I've seen no end of TVs and monitors that have had dry joints where the SCART socket is soldered to the PCB. It's due to the huge amounts of flexing caused by SCART plugs being pushed in and pulled out frequently. Crap design, really.
 
I'd recommend resoldering every joint on the SCART socket (there's only twenty!) and see if that improves the situaton. Don't waste your time using lead-free solder, use the proper stuff as that's what Sony used when they built it.
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Offline redbox

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I have just bought myself a Sony Trinitron 14" CRT TV (model KV-14LT1U) from Gumtree for £10[nb]In true Gumtree style he tried to tell me it was £20 as he'd reduced it from £40, but I stuck firm and in the end he gave it to me for £10. And it came with the remote. Result.[/nb].

I got it because I was fed up of using LCD TVs for retro gaming and wanted a nice CRT.

I tried my PS1/2 first and it was great and then I tested my 6128 via SCART cable and the result is just awesome.  It's like a CPC monitor but much cleaner whilst still retaining the CRT loveliness. 

But best of all I tried Relentless (which I am pretty sure uses R3 scrolling) and it works perfectly... I thought no known TVs via SCART had managed this so far...?
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Offline TFM

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Good luck for you!


Yes, the Sony Trinitron was the best choice back the day as CTM replacement. Since then i don't think there was ever a better choice of an CRT. Enjoy.  :)
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Online Gryzor

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It's been many, many years since I hooked up a CPC via SCART. However, I remember that as a child, every time I did that I was in awe. A cinematic experience!!!
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Offline redbox

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It's been many, many years since I hooked up a CPC via SCART. However, I remember that as a child, every time I did that I was in awe. A cinematic experience!!!

I really can't believe how good the 14" Trinitron is - it's much better than a CTM but still looks like a CRT.

And the R3 hardware scrolling works too... and still no-one has confirmed if this is the first/only TV that can do this via SCART...???
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Offline SyX

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I really can't believe how good the 14" Trinitron is - it's much better than a CTM but still looks like a CRT.
Yes, i can not agree more and you can play with the NTSC mode, for example in Pac-Man. 

And the R3 hardware scrolling works too... and still no-one has confirmed if this is the first/only TV that can do this via SCART... ???
Well, you should search in the forum, R3 works perfectly in CRT TVs attached by scart.

In the last decade i have only used my CPCs with that configuration (i have tested in various Sony, Samsung, Telefunken, ...  CRT TVs), because as you have said, it's much better than using an old CTM (bigger overscan, unpainful ntsc mode, better and vibrant colours, more control over the image configuration, ...).

And every time that i comment about a new game and publish photos, they are from my CPCs attached by scart to the CRT TV. For example, i wrote about it in the threads of Edge Grinder or Super Edge Grinder, both use the R3 trick and i helped to Axelay to test the scroll of his games in this configurations, and i confirm him that his super smooth scrollers and splits worked REALLY GREAT :) :) :)

Ups, and i don't know if you remember but i told you about "how i loved to play Subtera Puzlo in my CPC attached by scart to my CRT TV"  ;D
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Offline redbox

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Well, you should search in the forum, R3 works perfectly in CRT TVs attached by scart.

Aha, this is the key then - R3 doesn't work with LCDs by SCART, but it does work with CRTs via SCART.  Thank you, this had been bugging me for a while...!

Ups, and i don't know if you remember but i told you about "how i loved to play Subtera Puzlo in my CPC attached by scart to my CRT TV"  ;D

Well I am programming a new game engine and I tested it today on my real 6128 and 14" Trinitron and it looked great  ;)

But the border also told me that my dirty tilemap engine needs to be a lot faster (which is not so great haha!!!)  8)
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Offline ralferoo

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Aha, this is the key then - R3 doesn't work with LCDs by SCART, but it does work with CRTs via SCART.  Thank you, this had been bugging me for a while...!
Yes, whether the horizontal scrolling works or not is all dependant on the monitor response to the internal oscillator being out of sync with the HSYNC.

On all NTSC and PAL TVs, the line frequency is 15625Hz (or 1/64us) and the signal is corrected at a rate proportional to the phase difference between the two signals. I don't know of any requirement on the behaviour of this response, but most 15.625kHz monitors do tend to behave very similarly in pratice.

LCD TVs on the other hand tend to be designed assuming a VGA clock, and so are typically 31.25kHz or higher. When the HSYNC is moved slightly (as is done for the smooth scrolling on the CPC), the phase difference is therefore doubled (or more) and so the monitor corrects itself at a faster rate.

The upshot of this is that the scroll isn't half a character as intended, but instead a whole character or more, and then when the scroll is reversed it can shoot back too far the other way too. This generally results in a signal that's wobbling from side to side as well as scrolling, and so it looks more jumpy than if no "smooth scrolling" is attempted at all.
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Offline redbox

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Excellent, a hardware technical explanation that I can actually understand - thanks!
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