connecting to Digital TV

For experts to discuss very technical stuff and newbies to ask why the Spectrum they bought off ebay doesn't work.
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1024MAK
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Re: connecting to Digital TV

Post by 1024MAK » Thu Mar 22, 2018 8:04 pm

denjerus wrote:
Sat Mar 17, 2018 12:25 pm
Rummaging through my underground Attic I rediscovered about 300 old Spectrum games, 3 old 48K spectrums and a Spectrum128+.
ZX Spectrum 16k, ZX Spectrum 48k and ZX Spectrum+ machines all have an internal "loud" speaker (although not that loud, especially with early issue machines ...), but none of these beep when powered up.

So you don't need to connect any display to see if they are working. Power on and press and hold a letter or number key, and if it is working, you should hear the key "click" noise.

Reset (power down/up with the rubber key machines) and blind "type" BEEP 5,5
That is press [EXTEND MODE] (a key on the plus, [CAPS SHIFT] and [SYMBOL SHIFT] on the rubber key), then press and hold [SYMBOL SHIFT] while pressing [Z], then enter [5][,][5][ENTER].
Note on the rubber key, you get a comma [,] by pressing [SYMBOL SHIFT] and [N].
You should then hear a tone from the speaker.

Of course, if the keyboard membrane has failed, part or all of the keyboard won't work, and membrane failure is rather common with machines that have been used a lot.

If you have a TV with a composite video input (normally the physical connector is a phono / RCA / Cinch connector with yellow insulation or a SCART connector) then a ZX Spectrum 16k, ZX Spectrum 48k or ZX Spectrum+ machine can be modified fairly easily to output composite video instead of UHF.

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1024MAK
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Re: connecting to Digital TV

Post by 1024MAK » Thu Mar 22, 2018 8:12 pm

Oh, and some 'digital' TVs are capable of receiving and displaying the analogue UHF TV signal from the 1980s and 1990s computers.

I have a Sharp AQUOS LCD TV that works okay. You most likely will have to use the manual channel search and the fine tune controls though. Start with TV 'channel' frequency 35, 36 and 37 including in between channels. This is because the modulators used in the Sinclair machines is purely analogue and does not output on an exact TV standard frequency.

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Re: connecting to Digital TV

Post by Guesser » Thu Mar 22, 2018 9:38 pm

1024MAK wrote:
Thu Mar 22, 2018 8:12 pm
Oh, and some 'digital' TVs are capable of receiving and displaying the analogue UHF TV signal from the 1980s and 1990s computers.
I don't think I've seen a digital terrestrial tv that doesn't have an analogue tuner yet. Maybe some so-called "smart" ones?
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balford
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Re: connecting to Digital TV

Post by balford » Fri Mar 23, 2018 12:57 am

Guesser wrote:
Thu Mar 22, 2018 12:08 am
I feel like that article misses a trick by not also describing the mods to put audio on pin 3 and the second 12V on pin 5. One SCART cable pinout to rule them all (and fully support all the SCART signals) :)

I suppose they're somewhat more involved on the 128, needing wire to patch signals across.
Indeed, kinda wanted to steer away from anything too complex in that one, it’s a ‘get you going’ article first and foremost.

There are plenty of other corners of the interweb that can go into that level of excruciating detail 😀
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Re: connecting to Digital TV

Post by Guesser » Fri Mar 23, 2018 1:03 am

balford wrote:
Fri Mar 23, 2018 12:57 am
Indeed, kinda wanted to steer away from anything too complex in that one, it’s a ‘get you going’ article first and foremost.
Indeed, "patch wires across the board" is a bit "scare people away". On the other hand switching the +2 over to SCART is just more of the same with links :)

Maybe I should write my own page about SCART cables and mods... with blackjack! and hookers! In fact, screw the SCART cable thing.
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Re: connecting to Digital TV

Post by denjerus » Fri Mar 23, 2018 1:57 pm

Many Thanks again to all. Especially Guesser who prompted me again to try the analogue route. Using your wisdom , sir I managed to tune the 128 and one of the 48K speccies to my older DVB TV. Results show a kind of output to the TV.
Image
This first image is the output from the 48K spectrum, accompanied by a lot of white noise.
Image
This was what the 128K spectrum + looked like, similarly with white noise.
The 48K spectrum did beep a lot and produced the wail it used to when loading a programme but the plus unit provided no key sound output, even when I tried listening with headphones plugged into the ear socket.
I suspect these are possibly terminal indications for an amateur like me but there seems to be a market on ebay for spares and repairs, and all the software I have to go with them.
Unless you know differently of course.
Again many thanks to all who have contributed to this posting, it has served to illuminate my inadequacies in this field .
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