#I've Got 17 Inches Now!!
9 messages in this thread
I have just acquired a 17 inch Mitsubishi C-3920 monitor for evaluation.
This is an old 1986 model, but has been in storage for the last 4 years.
The manual claims that it is a "multi frequency use" high resolution color
display monitor. The spec page claims the following:6
Scanning Frequency:6
a) Vertical Frequency : 40-70 Hz6
b) Horizontal Frequency : 15.5 KHz 23.5 KHz6
The input connectors are the BNC type for R-G-B and composite or divided
sync. I have connected it to my Amiga 1000 and it works ok, _except_ I have
to switch the loop-through for the composite sync as if I had another load
downstream. This is _only_ the composite sync. Is this because the
horizontal sync is not matched? I lost my schematics and specs for my 1000
in a recent move, and I don't remember the spec. Will this monitor work
with other Amiga's, esp. the ones of the future? It would be very cheap for
me to buy, but I will change my Amiga one day (hopefully b4 Xmas 🙂 and if
it works with the 3000 or the 4000, that would be great.6 6
ADVthanxANCE,6
David6
PS The manual has a page for setting jumpers on the PCB-DEFL for hor. freq.
selection, and the chart lists like this:
LOW 15.5/18.5
HIGH 18.5/23.5
Does this mean it will sync to 18.5 no matter what the setting?
David,
The monitor will work for you at standard frequency, 15.75 KHz, but not
with the deinterlacer in the A3000, which requires 31.5 KHz. To restate,
it would work with an A3000, but only in the same way it works on your
A1000 – with interlaced video (and flicker). Depending on how well you
tolerate flicker, if the price is right, it might be worth having a 17"
monitor.
My guess on the jumper settings would be that you're actually choosing LOW
or HIGH with the jumper labeled LOW, and choosing which HIGH with the
jumper labeled high.
It's sort of a moot point, though, since only the 15.75 setting will work
with an Amiga.
Hope this helps, 8)
David
David,
Actually, I am using it in interlace mode for WB and View! It has _very_
long persistence phosphors, so I see _no_ flicker at all. However,
animations leave a trail on the screen. This is not a big problem since the
only animation I normally see is from games, and I can live with that.
Since it will not work with the deinterlacer in the 300, does that preclude
the use of certain screen modes? If so, which ones?
Thanx for your response.
PS A huge moniter is a very nice addition to a computer system!!! 🙂
David
David,
You won't be able to use any of the Productivity modes, which sync at 31.5
KHz horizontal, just like the deinterlacer.
I've recently hooked up my A500 to a 20" TV with video inputs for my
daughters. I know what you mean about how nice the larger monitor is.
Interesting thing is that even though a Nintendo is hooked up to the same
set and either one can be played at the touch of a button, they have
almost exclusively used the A500 since it's been available to them. (I
say _almost_ because I'm not around all the time to watch them. To the
best of my knowledge, they haven't played it at all.) Before, when the
choice was to play on the A500 with a 13" screen or Nintendo on the 20"
TV, they'd usually opt for the Nintendo. Maybe there's something to CDTV
after all?
David
David,
My *guess* is that the jumpers are to set the range of the
horizontal scanning circuitry. Low would be for any horizontal frequence
range between 15.5kHz and 18.5kHz and the high would be for horizontal
frequencies between 18.5 and 23.5 kHz.
In your case, you'd want the jumper on the low position.
As to why you need an additional load on the composite sync line,
there could be several reasons for that…if it works with an external
load…I wouldn't worry about it.
Don
Don,
The funny part is that I don't have an external load on the sync line. I
just flick the switch to the "high" impedance setting and there is nothing
connected to the loop-through BNC connector. If I set it to 75 ohms, I lose
the entire picture on the moniter. There is a switch inside the monitor for
Int/Ext sync, and when I tried that at Int, nothing worked, so I leave it
set at Ext, with the sync line set to "high". I don't think this will cause
any damage, but I would like to be sure. Any info about that?
Thanx for your help.
David
The Amiga's composite sync output is a TTL signal, not 75 ohm. The
unterminated switch position is correct for this and shouldn't cause any
problem provided that the monitor can handle the 5 volt signal (which I
expect it can). Peter.
Peter,
Since you seem to know about monitors, what would you think a fair value
of this monitor is? Specs again:
Mitsubishi 19" (Yes, I just noticed it says 19 " on the manual!!)
High resolution Color Display Monitor
Connectors: 5 BNC for R-G-B plus comp/hor sync and v/sync
75 Ohm termination switchs
Blanking:
Horiz < 9.0 us
Vert < 850 us
Scanning Freq:
Horiz 15.5 KHz 23.5 KHz
Vert 40-70 Hz
Max Eff Screen Size: 350(W) x 265(H) mm
Also On the back of the Monitor, on the serial number plate, is a date
of 1986.
Thanx
David
David,
Peter is the expert on monitors so I'm sure his advice is correct.
Don