25K7191 in a 720 Degrees?

ChaosJohn

Active member
Joined
Feb 8, 2005
Messages
1,640
Reaction score
18
Location
Burbank, California
Does anyone know if a 25K7191 monitor will work in a 720 Degrees? I broke the neckboard on my 25K5515, and you know they're harder to find than honest politicians. I might be able to buy a 25K7191. So I'm debating whether it would be easier to fix the neckboard on the 5515, or (if possible) to buy and fix the 7191.

Preferably, I'd like a case where someone has actually done this - they have a 7191 in their 720 and it works.

thanks,
ChaosJohn
 
wells

I will check for 5515 neck board this weekend.
 
Why don't you fix your neckboard?

And IIRC a K7000 won't work because it's standard res, and 720 is medium.

[best whiny voice]Because it's haaaaarrrrd[/best whiny voice]

I've never actually fixed a neckboard that's completely cracked in two parts before. Have you? Did you find it easy or hard? I've done 10 or 12 cap kits, and I find them to be pretty reasonable. Is it much harder than that?

I've seen the Bob Roberts page where you expose the connections and solder paper clips to join across the gap, but I'm skeptical (don't know why, everything else I've picked up from Bob Roberts' site has worked).

Besides, the 7191 I might be able to get is in low screen burn, but unknown working condition so I can get it cheap.

According to The manual for the K7000 series, on page 2 it lists the resolution of the 25" monitor as 560x240. That's certainly medium resolution, I'm just not sure if it's a comparable resolution to the K5515 (which doesn't seem to mention a resolution in it's manual)
 
Bob Roberts had an amusing article on how to fix a neckboard that was cracked in half using paperclips lol

depends mostly on where it's cracked I guess. I think most of that stuff can be repaired using jumper wires to replace the traces that are gone.

show a picture of the broken neckboard, I'm certain someone can give you a guesstimation on what to do with it.
 
I'm just not sure if it's a comparable resolution to the K5515 (which doesn't seem to mention a resolution in it's manual)

Really?

5515cover.jpg
 
Yes, I've done it. I used paperclips, just like Bob did. It was that or toss the monitor. And since they're not making them any more, keeping them around as long as possible just makes sense.
 
It's really not difficult to repair, though from a quick look at the manual of the k5515 and a k4900, it looks like the neckboards are the same, or very close to the same. So, if you have a k4900, you may be able to just swap neck boards (though you should verify first).

About repairing with paperclips... I dunno, it probably works, but I personally just jumper them with real wires and use something to keep the board from flexing (epoxy, or metal trim along the edge, or sometimes with really wide traces it's stiff enough without anything). I just don't think paperclips are the best conductive wire material... they have a coating on the outside which makes them shiny, but flakes off, and I believe it's made of steel, which isn't as good of a conductor as copper, and I'd assume is harder to solder to. If you want something sturdier than component leads or braided wire, solid conductor copper wire (like Romex) works well and is stiff.

DogP
 
What's pixel count have to do with this argument ?
CGA (standard) can run in the neighborhood of 640x200.

Standard resolution runs at 15khz, medium is at 25khz...... that's where the huge difference comes into play.
The pixel ratio is only a piece of the puzzle, the frequency at which they run is where they are different.

The K7000's are standard resolution, the K5515 is a medium resolution.
720 outputs medium resolution frequencies, regardless of pixel ratio.

If you need someone to repair your neckboard for ya, just ask.
 
Atari games video standards

Code:
ATARI GAMES VIDEO STANDARDS


                   STANDARD RESOLUTION

          HORIZONTAL                    VERTICAL
Scan Frequency: 15.72 KHz    Scan Frequency: 60.0 Hz
   Scan Period: 63.6 µSec       Scan Period: 16.7 mSec
  Active Video: 46.9 µSec      Active Video: 15.3 mSec
   Video Delay: 11.9 µSec       Video Delay:  1.2 mSec
    Sync Pulse:  4.7 µSec        Sync Pulse:  0.2 mSec
     Scan Line: 456 Pixels           Screen: 262 Lines
    Resolution: 336 Pixels       Resolution: 240 Lines
    Clock Freq: 7.16 MHz


                   EXTENDED RESOLUTION

          HORIZONTAL                    VERTICAL
Scan Frequency: 16.50 KHz    Scan Frequency: 53.0 Hz
   Scan Period: 60.6 µSec       Scan Period: 18.9 mSec
  Active Video: 48.0 µSec      Active Video: 17.4 mSec
   Video Delay: 11.9 µSec       Video Delay:  1.2 mSec
    Sync Pulse:  3.9 µSec        Sync Pulse:  0.2 mSec
     Scan Line: 646 Pixels           Screen: 312 Lines
    Resolution: 512 Pixels       Resolution: 288 Lines
    Clock Freq: 10.67 MHz


                    MEDIUM RESOLUTION

          HORIZONTAL                    VERTICAL
Scan Frequency: 25.00 KHz    Scan Frequency: 60.0 Hz
   Scan Period: 40.0 µSec       Scan Period: 16.7 mSec
  Active Video: 32.0 µSec      Active Video: 15.4 mSec
   Video Delay:  7.2 µSec       Video Delay:  1.2 mSec
    Sync Pulse:  4.0 µSec        Sync Pulse:  0.2 mSec
     Scan Line: 640 Pixels           Screen: 416 Lines
    Resolution: 512 Pixels       Resolution: 384 Lines
    Clock Freq: 16.00 MHz


                     VGA20 RESOLUTION

          HORIZONTAL                    VERTICAL
Scan Frequency: 31.55 KHz    Scan Frequency: 70.0 Hz
   Scan Period: 31.7 µSec       Scan Period: 14.3 mSec
  Active Video: 25.6 µSec      Active Video: 12.2 mSec
   Video Delay:  5.7 µSec       Video Delay:  1.1 mSec
    Sync Pulse:  4.0 µSec        Sync Pulse:  0.2 mSec
     Scan Line: 634 Pixels           Screen: 450 Lines
    Resolution: 512 Pixels       Resolution: 384 Lines
    Clock Freq: 20.00 MHz

-Mike
 
IT IS ALIVE!!! (well sorta)

I patched the neckboard back together. Now instead of seeing nothing I get a solid light blue screen, but it is lighting up.

Don't know if the 720 board set is working, so I'll try it with my Paperboy next to see if I get a proper image.
 
By Jove, I got it!!!

I hooked it up to my Paperboy and it worked.

Once again my actual arcade repair skills exceed what I actually think I'm capable of. :)
 
No, it's not a 7191. Someone here on KLOV had a "medium res 7191" listed among other things, but as someone here pointed out 7191's are NOT medium res.

I fixed the neckboard on my 5515
 
Here are a couple of pics - the repaired neckboard, and Paperboy showing on the monitor after the repair (it appears normal in person, the horizontal bar is a result of taking a photo of a monitor of course). I used paper clips in three places, as recommended by Bob Roberts, and just soldered over a couple of other places.
 

Attachments

  • neckboard1.jpg
    neckboard1.jpg
    64.4 KB · Views: 27
  • neckboard2.jpg
    neckboard2.jpg
    19.3 KB · Views: 16
Back
Top Bottom