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48K rgb output? Also, OTLA.

Ricardo99Ricardo99
edited July 2014 in Hardware
A couple of weeks ago I scored 2 48K Spectrums on eBay for ?27 with 1 PSU, 1 TV cable and about 10 tapes....score or what!!!!

One turned out to be an Issue 4S the other an Issue 2 with the tranny over the Z80.

So I replaced all the caps on both boards (just because) and the 5v reg on the issue 4S as it was only giving 4.3V after being on for about 3 minutes or so and the Speccy switched off at about 4.6v the new reg fixed the voltage and the system now runs smooth. :)

Question time:

Ok, so I have done the composite mod conversion on the 2 48K Speccys and I do get an output, trouble is it still doesn't work on my LCD tv without the "horizontal hold" problem due to the "not quite right" pal output of 80's computers....

So, I have a GBS8200 which I run my +2 through via RGB, after modding the signal output to filter out the noise as many people on here have noted, then hooked it up to my old 21" PC TFT monitor and the picture looks spanking!

So I tried putting the 48K through it, but the GBS8200 board does not accept composite input :( Has a composite input cable but apparently it needs other signals to work.

So, now the question, is there a way to get the 48k to hook up to an RGB input? 48K to SCART RGB would be ideal really as I know that signal works flawlessly through the GBS8200.

Right, now the OTLA question:
I have put a few different tzx and tap files through OTLA and the output mp3 or wav file is about 8 seconds long and none of the Speccys will load anything from them. So i tried recording from my tape player to my phone Bosconian 87 then playing it from the phone to the Spectrum, just to make sure it wasn't a connection problem, but it worked perfectly . Any ideas ?

Cheers for the replies, feel free to point out how daft I am being here.

Richard.
Post edited by Ricardo99 on

Comments

  • 1024MAK1024MAK
    edited June 2014
    The ULA in 16k and 48k Spectrums generates colour difference and luminance signals only. There are no RGB video signals in a 16k or 48k Spectrum.

    Mark
    Sinclair FAQ Wiki
    Repair Guides. Spanish Hardware site.
    WoS - can't download? Info here...
    former Meulie Spectrum Archive but no longer available :-(
    Spectranet: the TNFS directory thread

    ! Standby alert !
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    Looking forward to summer in Somerset later in the year :)
  • Ricardo99Ricardo99
    edited June 2014
    Yeah, I know that. But I am sure there is a way to get a video signal out of the 48K system and either into the VGA input at the correct scan rate or at the very least into the GBS8200 so I can get it into the VGA input.

    I have seen something called the "VGA-box" which seems to do this (at least that's what I think I saw) but when I looked it was ?70 or there abouts, that's three times what I paid for the 2 spectrums....
  • BloodBazBloodBaz
    edited June 2014
    The SPECTRA Interface provides a plug-in solution by recreating the signal from scratch and outputting it to RGB SCART. Includes a host of other features too.
  • fogfog
    edited June 2014
    I do have an RGB interface, well there are no doc's with it that goes in the expansion port.. not tested it though.

    I did see an rgb interface on ebay, but it was rather expensive vs say spectra.
  • Ricardo99Ricardo99
    edited June 2014
    Ah yes, Spectra was one of the things I looked at, but at ?60 +p&p (?4.50) seems a bit much to be honest.

    Might have to resort to it later in the year mind.....
  • fogfog
    edited June 2014
    just keep an eye on ebay also , they do turn up .. I haven't tried the rgb lead I got as I think it's the sort made for BBC cub monitors.
  • WinstonWinston
    edited June 2014
    Ricardo99 wrote: »
    Ah yes, Spectra was one of the things I looked at, but at ?60 +p&p (?4.50) seems a bit much to be honest.
    .

    60 + p&p is an absolute bargain. You have to remember that it's not like he's making millions at at time in China, these are extremely limited production runs meaning you can't take advantage of automatic pick and place assembly, and be able to spread your PCB engineering costs across a few million units. Unfortunately cheap Chinese electronics has given us all a false expectation on what electronics should cost.

    It's doubtful that the guy who makes the Spectra ends up making any money from doing this, and he's probably having to assemble and test the boards himself manually.

    You can get VGA boxes for about 35 quid. I have one, it's reasonably OK, but nowhere near as good as proper RGB output.
  • orangeorange
    edited July 2014
    there's RGB converter by Pera Putnik:

    http://piters.tripod.com/uvyrgb.htm
  • Ricardo99Ricardo99
    edited July 2014
    Ah yes, I had discovered that a couple of weeks ago. Could not find enough information (even on that site) to get a complete idea of the circuit. I'm sure it's all there, but as I am electronically competent at a basic level I am very much not up on those sorts of electronics, though I am learning.

    I might, if I suddenly come into some money from somewhere...., either build that circuit or just go buy a Spectra :)


    I think I have the OTLA problem solved as well, the "accelerated" option seemed to not be putting the full information into the initial loading tones, so I switched that off and managed to get a couple of games to load....:-D
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