| Poster | Thread |
 Trekiej
|  |
15.75 KHZ Question
Posted on 14-Nov-2018 22:41:31
| | [ #1 ] |
|
|
 |
Cult Member
 |
Joined: 17-Oct-2006
Posts: 890
From: Unknown | | |
|
| Is there a safe way to test a monitor or tv to see if this frequency can be used?
Also can a 31.5 KHZ signal be synced down to 15.75 KHZ?
For example, if I wanted to connect it to a Chroma Keyer. _________________
John 3:16 |
|
| Status: Offline |
|
|
newlight
| |
Re: 15.75 KHZ Question
Posted on 14-Nov-2018 23:17:08
| | [ #2 ] |
|
|
 |
Super Member
 |
Joined: 10-Sep-2007
Posts: 1935
From: Somewhere in Spain | | |
|
| @Trekiej
Yes Probably but I don't know how.Let's wait for another thread or answers on this one
Hopefully...GOOD LUCK AMIGO!!! _________________
AMIGA 500 1.5 MB ACA500/ACA1232 accelerators
AMIGA 500 German
CD32 unexpanded
Amiga 1200 Tower on AmigaKit since years
AMIGA 1300 030/50 Mhz/32 MB WB 3.9 with lots of games&demos
AMIGA ONE XE G3 PPC 800 Mhz/1 GB RAM/RADEON 9250 128 MB/SATA CONTROLLER |
|
| Status: Offline |
|
|
pavlor
| |
Re: 15.75 KHZ Question
Posted on 15-Nov-2018 15:25:13
| | [ #3 ] |
|
|
 |
Elite Member
 |
Joined: 10-Jul-2005
Posts: 9584
From: Unknown | | |
|
| @Trekiej
You should read documentation of said monitor/TV as there is no general rule.
Never heard about down-syncing in the Amiga context.
There are some cheap double-sync box for retro-gaming purposes, but I don´t know, how compatible these are with Amiga. Real Amiga scan-doubler would be of course the best solution (and most expensive). |
|
| Status: Offline |
|
|
g01df1sh
| |
Re: 15.75 KHZ Question
Posted on 15-Nov-2018 16:22:57
| | [ #4 ] |
|
|
 |
Super Member
|
Joined: 16-Apr-2009
Posts: 1777
From: UK | | |
|
| What is make and model of TV/monitor ?
_________________
A1200 ACA1232 128MB Indivison MkIICr
Elbox empty Power Tower
RPi3 Emulating C64 ZX Atari PS BBC
Wii with Amiga emulation
Vampire v4 SA |
|
| Status: Offline |
|
|
evilFrog
| |
Re: 15.75 KHZ Question
Posted on 15-Nov-2018 21:10:45
| | [ #5 ] |
|
|
 |
Regular Member
 |
Joined: 20-Jan-2004
Posts: 397
From: UK | | |
|
| @Trekiej
I don’t know for sure, but I strongly doubt you would damage a modern LCD or other flat panel display by just trying it and seeing what happens.
Older CRTs are a different matter, you’d be best off checking the manual for those. _________________
"Knowledge is power. Power corrupts. Study hard, be evil." |
|
| Status: Offline |
|
|
OneTimer1
| |
Re: 15.75 KHZ Question
Posted on 16-Nov-2018 13:34:05
| | [ #6 ] |
|
|
 |
Cult Member
|
Joined: 3-Aug-2015
Posts: 974
From: Unknown | | |
|
| @Trekiej
Quote:
Is there a safe way to test a monitor or tv to see if this frequency can be used?
|
No, some monitors could only be used with the frequency they are designed for.
Quote:
Also can a 31.5 KHZ signal be synced down to 15.75 KHZ?
For example, if I wanted to connect it to a Chroma Keyer. |
No, usually not. |
|
| Status: Offline |
|
|
Trekiej
| |
Re: 15.75 KHZ Question
Posted on 16-Nov-2018 13:57:34
| | [ #7 ] |
|
|
|
Cult Member
|
Joined: 17-Oct-2006
Posts: 890
From: Unknown | | |
|
| Thanks, I have two Vizio TVs at 19 inch TV and a 23 inch TV.
Epsilon on his Blog has a monitor that will sink down low enough.
I wish we could find more monitors like that.
how about making a CRT style hood that will bolt to the back of an LCD TV to make it look like 1084?
_________________
John 3:16 |
|
| Status: Offline |
|
|
Deniil715
 | |
Re: 15.75 KHZ Question
Posted on 16-Nov-2018 20:47:04
| | [ #8 ] |
|
|
 |
Elite Member
|
Joined: 14-May-2003
Posts: 4236
From: Sweden | | |
|
| @Trekiej
TVs always support 15kHz. Connect to the SCART port. It is 15kHz only.
If it has a VGA port it will do 31kHz and up. _________________
- Don't get fooled by my avatar, I'm not like that (anymore, mostly... maybe only sometimes) 
> Amiga Classic and OS4 developer for OnyxSoft. |
|
| Status: Offline |
|
|
OneTimer1
| |
Re: 15.75 KHZ Question
Posted on 17-Nov-2018 15:24:49
| | [ #9 ] |
|
|
|
Cult Member
|
Joined: 3-Aug-2015
Posts: 974
From: Unknown | | |
|
| @Trekiej
Quote:
I wish we could find more monitors like that.
|
Get a LCD-TV they can deisplay PAL/NTSC, RGB with 15,75kHz, VGA, HDMI, ... |
|
| Status: Offline |
|
|
Trekiej
| |
Re: 15.75 KHZ Question
Posted on 18-Nov-2018 19:57:21
| | [ #10 ] |
|
|
|
Cult Member
|
Joined: 17-Oct-2006
Posts: 890
From: Unknown | | |
|
| Thanks everyone, I need to get one of the authentic 23 to 15 pin adapters.
An Amiga 1000 Genlock will be on my list for next year.
Maybe an external genlock too.
I do like those NTSC camera switchers I see on Ebay.
They have other units like a Titler that can be added.
I do have two Laser Disc players and a Applied Magic Screenplay.
_________________
John 3:16 |
|
| Status: Offline |
|
|
bison
 | |
Re: 15.75 KHZ Question
Posted on 18-Nov-2018 23:28:50
| | [ #11 ] |
|
|
 |
Elite Member
|
Joined: 18-Dec-2007
Posts: 2112
From: N-Space | | |
|
| @Trekiej
Quote:
| how about making a CRT style hood that will bolt to the back of an LCD TV to make it look like 1084? |
Back in the day my main objection to the 1084 was that... it looked like a 1084. 
_________________
"Unix is supposed to fix that." -- Jay Miner |
|
| Status: Offline |
|
|
BrianHoskins
| |
Re: 15.75 KHZ Question
Posted on 19-Nov-2018 11:19:27
| | [ #12 ] |
|
|
 |
Cult Member
|
Joined: 4-Jan-2003
Posts: 726
From: South Wales, UK | | |
|
| @Trekiej
Is there a safe way to test a monitor or tv to see if this frequency can be used?
FOR CRT:
The safest way would be to read the manual. But as a rule of thumb, I would say it's a fair bet that any CRT monitor that was manufactured during this century can be tested safely by simply applying the input signal and seeing if a picture is displayed.
If you apply a signal with an unsupported HSYNC then I would expect all 'modern' CRT monitors to simply reject the signal and show an error graphic on the screen.
For CRT monitors that were produced last century, then really you need to read the manual and only apply the correct signals to it.
The reason is that the horizontal scan on CRT monitors is achieved by ramping the current in a deflection coil, then switching-off the coil at the end of line and allowing the reverse voltage to generate a very fast "flyback". As you might imagine, there is a lot of energy at work here.
Horizontal scan circuits on these monitors may be designed with a specific horizontal scan rate in mind. If you then try to apply a lower scan rate, the deflection coils shall be subjected to a longer than expected ramp, resulting in any of the following:
Deflection coil saturation (a saturated coil does not behave correctly in this context)
Significant over-current, especially at end of line scan (coil switch-off) damaging horizontal scan circuit.
Switch saturation in the horizontal scan circuit, causing damage due to excess power dissipation in the switch.
FOR LCD:
Since LCDs do not have an analogue line scan circuit or associated deflection coils, all LCD monitors are safe to test by simply plugging in the video signal and seeing if a picture is displayed.
Last edited by BrianHoskins on 19-Nov-2018 at 11:30 AM.
Last edited by BrianHoskins on 19-Nov-2018 at 11:22 AM.
Last edited by BrianHoskins on 19-Nov-2018 at 11:19 AM.
|
|
| Status: Offline |
|
|
Trekiej
| |
Re: 15.75 KHZ Question
Posted on 20-Nov-2018 2:18:57
| | [ #13 ] |
|
|
|
Cult Member
|
Joined: 17-Oct-2006
Posts: 890
From: Unknown | | |
|
| @BrianHoskins
Cool, thanks. _________________
John 3:16 |
|
| Status: Offline |
|
|
10 crawler(s) on-line.
133 guest(s) on-line.
0 member(s) on-line.
