Hi all.
This is a problem I’ve got with several Zx81 of mine. If a press some keys, sometime the screen ‘lifts up’ showing this horizontal black line. If i reposition slightly the video cable the problem temporary goes off and then goes back.
This happens either with composite mod, either without. I’m mounting vla81 as Ula.
Thanks in advance,
Davide
Sometimes Screen lifts up when pressing keys
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Re: Sometimes Screen lifts up when pressing keys
Something is loose. Do you have an expansion plugged in?AmintaSpectrum wrote: ↑Sun May 23, 2021 8:12 pm Hi all.
This is a problem I’ve got with several Zx81 of mine. If a press some keys, sometime the screen ‘lifts up’ showing this horizontal black line. If i reposition slightly the video cable the problem temporary goes off and then goes back.
This happens either with composite mod, either without. I’m mounting vla81 as Ula.
Thanks in advance,
Davide
7A425EEE-9DDF-4158-8219-ED45847C1B8F.jpeg
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- Posts: 18
- Joined: Tue Jul 04, 2017 12:12 am
Re: Sometimes Screen lifts up when pressing keys
No expansion, same problem on several Zx81, can be the Philips Monitor?
Re: Sometimes Screen lifts up when pressing keys
Just to check... be sure you are not in FAST mode..
Ernesto
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come
ZX80 USA, ZX81UK, ZX Spectrum, ZX Spectrum+, ZX Spectrum 128+ UK, ZX Spectrum +2/A, Sinclair QL, CZ1000, CZ1500, CZ2000, CZ1000Plus, CZ1500Plus, CZ Spectrum, CZ Spectrum Plus, TK83, TK85, TK90X, TK95. TS2068. And more to come
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Re: Sometimes Screen lifts up when pressing keys
Definitely worth trying different cables and a different monitor/TV.AmintaSpectrum wrote: ↑Sun May 23, 2021 9:48 pm No expansion, same problem on several Zx81, can be the Philips Monitor?
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
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Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
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ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
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- Posts: 18
- Joined: Tue Jul 04, 2017 12:12 am
- 1024MAK
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- Joined: Mon Sep 26, 2011 10:56 am
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Re: Sometimes Screen lifts up when pressing keys
The default on switch on for a ZX81 is SLOW mode, also known as compute and display.
To switch to FAST mode, use the FAST function on the F key. In this mode the machine will only produce a video picture when it is waiting for user input just like how the ZX80 works. If it is running a program, the display will blank (normally to black on a CRT display). The advantage is that the program runs much faster.
To return to SLOW mode, use the SLOW function (on the D key).
Note that the setting IS NOT retained between resets/power off/on, so a ZX81 will always start up in SLOW mode.
Mark
To switch to FAST mode, use the FAST function on the F key. In this mode the machine will only produce a video picture when it is waiting for user input just like how the ZX80 works. If it is running a program, the display will blank (normally to black on a CRT display). The advantage is that the program runs much faster.
To return to SLOW mode, use the SLOW function (on the D key).
Note that the setting IS NOT retained between resets/power off/on, so a ZX81 will always start up in SLOW mode.
Mark
ZX81 Variations
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.
ZX81 Chip Pin-outs
ZX81 Video Transistor Buffer Amp
Standby alert
There are four lights!
Step up to red alert. Sir, are you absolutely sure? It does mean changing the bulb
Looking forward to summer later in the year.