Dragons Lair bring up. No video at the moment

Raftman

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I'm bringing up a dragons lair cabinet and want to get video output so i can run diagnostics. The internals have been worked on before so I spent today figuring out how to wire power and figuring out what is original.


Picture of ntsc decoder board attached. I believe this is original. Should anything be connected to p204? There is replacement power supply so I do not see how this board gets power.


Also the monitor is a Zentih model, and I do not believe this is original.

I attached a scope to bnc input of the decoder board and not seeing anything.

So, I need some help testing the monitor, decoder board' and laser disc player. Any help geatly appreciated.

Also there is a board labeled sidam 11470. It has an edge connector and is spliced into some signals going to the main logic board. I don't know what this is. It is pictured here.

My main goal is to get video output so if i need another monitor or a dvd player to test i will do that. Thanks.
 

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I believe Sidam was the company that made the Italian Dragons Lair cabinets.
That's a Wells Gardner P371 NTSC board and P204 is for power and blanking input which comes from the monitor chassis board. Here's a link to info of this board at MikesArcade.
https://www.mikesarcade.com/cgi-bin/spies.cgi?action=url&type=info&page=wg-ntsc.txt
As for your monitor, Zenith is not the model just the manufacture of the picture tube. USA Dragons Lair games originally had either an Electrohome G07 with their NTSC reticular board or the Wells Gardner K4900 with the square NTSC board like the one you have.
 
Thank you for the quick and informative reply. I do realize that Zenith is the manufacturer and not that model. Regardless it is not the original equipment. Is the ntsc decoder board generic and works with this monitor.

I'll check the link you sent. In the dragons lair schematic package i downloaded from this site wasn't clear to me that the power connector went to the chassis board. I will look for the same signals on the Zenith board.

The cabinet is not with me so I can only visit every week or two.
 
Zenith is just the tube manufacturer and not the monitor manufacturer.
Take a pic of the monitor chassis and we'll tell you what arcade monitor you have.
Chances are it is an Electrohome G07.
 
What a DL looks from behind ...

dl6.jpg
 
Ah ok I didn't differentiate between the tube and monitor manufacturer. The back of the cab certainly looks familiar, though today i spent good chunk of time navigating spaghetti. The previous owner installed new power supply, by-passing the oem board, and frankly I'm not impressed with the twist and tape splices. I was going replace with butt connectors twist caps.

Thank you again - I'll have a bit of material to work through and prep for my next round of testing.

Do you have a recommendation for site(s) for replacement proms, diagnostic roms, or other parts of that nature? Besides ebay or whatever a google search pulls up?
 

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The sidam board looks to be a coin doubler circuit. I would remove it entirely.

You have your player ribbon cable plugged in backwards, the red strip must be on pin-13 not pin-1 like you would expect (this is just an odd quirk of Dragon's Lair).

Your NTSC board is the Wells Gardner Type. Your monitor may not be WG, so it's going to be difficult finding the proper voltage and blanking signal. I would ignore that for now, and simply connect an old TV and find out if the game is working. Does the game boot? Does the laserdisc play?
 
The sidam board looks to be a coin doubler circuit. I would remove it entirely.

You have your player ribbon cable plugged in backwards, the red strip must be on pin-13 not pin-1 like you would expect (this is just an odd quirk of Dragon's Lair).

Your NTSC board is the Wells Gardner Type. Your monitor may not be WG, so it's going to be difficult finding the proper voltage and blanking signal. I would ignore that for now, and simply connect an old TV and find out if the game is working. Does the game boot? Does the laserdisc play?

Thanks for the tip on the coin doubler circuit. Studying the schematics I could not find what this board was supposed to be doing so I'll leave it out for now.

The machine is about an hour away from me so I will not be back there until next weekend. So in the meantime I'll be preparing a list for what to check next. When you say the 'player cable is backwards' I assume you mean the ribbon cable coming from the laser disc player to the main logic board? That cable was already connected and I didn't think to check the polarity since the way the cable exited seemed to make sense. I just want to make sure you aren't talking about the score display cable (between display board at the top between speakers and the logic board).

However if that is backwards it could explain a lot. The laser disc player has power (I can see the red light on the front turn on) but I did not hear or feel any vibration or sign that the disc was spinning. If that connector is indeed backwards would that make sense?

When I power up the machine I get some random characters on the Player 2 display ad on the credits counter. No monitor output. They are static (not counting through characters like some of the test modes I read about in the manual).

For my next visit I will bring a separate working monitor and some BCN-RCA adapters. I need to learn a little about video standards but I assume the laser disc is outputting composite video through the BNC connector. If I connect that through an adapter to RCA I should be able to connect to, say, a Commdore 1702? Then I can at least get some diag info from memory and prom tests. We have 2 sets of proms and 2 main logic boards. I believe the previous owner was trying to patch together a working system and just gave up. If I can get a full diagnostic test output to an external monitor I can deal with figuring out the connections to the Wells-Gardner NTSC decoder board later.
 
Seems your monitor is a WG K7000 series.

Thanks VectorCollector. Following up on swood's advice I'm going to get a working monitor down there and see what I get.

I'll look at the youtube videos you linked and start digging through manuals for the WG decoder board and whatever monitor is actually in this unit.

It is nice to at least verify that the decoder board is not what is originally with the cabinet (hence why it's not matching the schematics).
 
Yes, the ribbon cable coming from the laserdisc player is 180 degrees off on the connector. Flip it around and see if the player spins up.
The player is almost always the problem with non-working Dragon's Lair machines, so if it spins-up and begins to play, consider yourself lucky. Otherwise you will need one of my Merlin boards along with a newer player.

All video in Dragon's Lair comes from the laserdisc, so you are right on target to bring another monitor to test with. But don't count too much on the diagnostics tests in Dragon's Lair, I've found them to be fairly useless. The beep sounds are the true indicator of a working board set.
Does it give you all three sounds after powering on?

The scoreboard will show a diagnostics test after the second beep. If you get a 1,2 or 3 in the left most digit of player-1, and some numbers in Player-2, then your main board is probably good. From your description, it sounds like you're getting that, so I'd bet the board in it now is OK.

It comes down to this..
Since you have extra logic boards, no doubt at least one will be working, and you will hear at least two beeps.
Your Monitor is not original, so you will have to figure out how to connect the NTSC board or replace the monitor.
Your Laserdisc player may or may not work. If it doesn't, you will need a LD-V8000 or Dexter replacement and a Merlin board.

Let us know what happens, and feel free to PM me if you have any specific questions
Good Luck!
 
Yes, the ribbon cable coming from the laserdisc player is 180 degrees off on the connector. Flip it around and see if the player spins up.
The player is almost always the problem with non-working Dragon's Lair machines, so if it spins-up and begins to play, consider yourself lucky. Otherwise you will need one of my Merlin boards along with a newer player.

All video in Dragon's Lair comes from the laserdisc, so you are right on target to bring another monitor to test with. But don't count too much on the diagnostics tests in Dragon's Lair, I've found them to be fairly useless. The beep sounds are the true indicator of a working board set.
Does it give you all three sounds after powering on?

The scoreboard will show a diagnostics test after the second beep. If you get a 1,2 or 3 in the left most digit of player-1, and some numbers in Player-2, then your main board is probably good. From your description, it sounds like you're getting that, so I'd bet the board in it now is OK.

It comes down to this..
Since you have extra logic boards, no doubt at least one will be working, and you will hear at least two beeps.
Your Monitor is not original, so you will have to figure out how to connect the NTSC board or replace the monitor.
Your Laserdisc player may or may not work. If it doesn't, you will need a LD-V8000 or Dexter replacement and a Merlin board.

Let us know what happens, and feel free to PM me if you have any specific questions
Good Luck!

Thanks a ton - I will certainly follow-up here with results and PM you if questions arise. I will not be back at the machine until weekend after next so this will be dormant for a bit.

At some point I did hear a beep or two and saw characters filling all of the player 2 displays - not sure about the player 1. When I was all done though it wasn't beeping - I suspect that the incorrect disc player orientation has something to do with that...


Lastly - I know I will need to construct a cable between the chassis board (and possible power supply) and the WG decoder board. The WG K7000 manual lists Wells Gardner part #'s for the headers on the chassis board - but I want to know the Molex part # so I can order the right size. Does anyone know this? I'll search other threads as it is probably likely already been answered somewhere else.
 
Round 2 with DL

Ok so I've studied a bit and made a couple of cables to connect power (15V or 12V) to the WG NTSC decoder board as well as RGB and positive composite sync (WG7000 series wants composite sync to HSYNC pin only - so VSYNC is left no connect monitor side.

Also I've been made aware of the laser disc ribbon cable polarity on the main board. I also have some bnc to rca (both gender directions) so I can test laserdisc player on external monitor or feed external video to ntsc decoder board.

One loose end I didn't find an answer to - blanking signal? The wg decoder board has a blanking input signal on the same header as power. The wg7000 service manual talks about a blanking signal being derived from other signals. QUESTION - where should blanking signal on ntsv decoder header go??

Thanks guys. Update later this evening.
 
Laser disc life?

Is there a way to verify the ld player outside of the machine? I'm not sure if this has a discrete play button or only controlled via the ribbon cable.

Current state is monitor displaying black signal. No beeps on startup. Next steps - swap main board with backup and try connecting ps2 to decoder board to check video quality.

This person bought this machine with a bag of spare parts so i know not everything will be working.
 
Is there a way to verify the ld player outside of the machine? I'm not sure if this has a discrete play button or only controlled via the ribbon cable.

Current state is monitor displaying black signal. No beeps on startup. Next steps - swap main board with backup and try connecting ps2 to decoder board to check video quality.

This person bought this machine with a bag of spare parts so i know not everything will be working.
The laserdisc player can be tested by connecting it to your TV. It should play the disc from start to finish. If it does, then you know the video out of the player is working.

Not knowing which LD player you have, my experience is most will just start playing. You can also build an adapter plug that allows you to jumper a few pins in the control port that will tell the player to play.

Scott C.
 
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If the laserdisc player is the LD-V1000, then no, it wont start without computer control, and there are no buttons on the front to press.

There is a trick to force it to start by shorting two pins on the control port, but let's wait and see if the computer will boot it up first.
 
Ok so I've studied a bit and made a couple of cables to connect power (15V or 12V) to the WG NTSC decoder board as well as RGB and positive composite sync (WG7000 series wants composite sync to HSYNC pin only - so VSYNC is left no connect monitor side.

Also I've been made aware of the laser disc ribbon cable polarity on the main board. I also have some bnc to rca (both gender directions) so I can test laserdisc player on external monitor or feed external video to ntsc decoder board.

One loose end I didn't find an answer to - blanking signal? The wg decoder board has a blanking input signal on the same header as power. The wg7000 service manual talks about a blanking signal being derived from other signals. QUESTION - where should blanking signal on ntsv decoder header go??

Thanks guys. Update later this evening.
If you have a 19"K-7000 monitor in your game, dose it have the vertical board with an 8 pin plug? If not then the monitor is not set up for the NTSC decoder board. I have a 25"K-7000 I bought some years ago that came out of a Dragon's Lair 2 which still has the NTSC card connected but I never tested it to see if it works. I did find a picture I took showing it's connections. The plug has 3 wires, black,blue and green. If your monitor chasse dose not have this connection their are other ways around it but it's not a plug and play solution. Just do a search on the Dragons Lair Projects archives for monitor and you will find many posts about this problem.
http://www.dragons-lair-project.com/community/forums/archives/archives.asp?Action=ExecuteSearch
Here is one page I found wile doing the search which modifies the NTSC so it can be used with any standard monitor.
http://users.tpg.com.au/malcor/WG_NTSC.txt
I have a 19"K-7000 monitor in my Dragon's Lair but I took the easy way out. I used the Electrohome NTSC which dose not need the blanking input. You can see on my monitor chasse the blank pin holes where the vertical card would install but even if you had the card their may be other modifications made to the chasse to make it work. Maybe someone else knows more and can chime in.
25"K-7000 DL2 monitor
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My Dragon's Lair with 19"K-7000 and Electrohome NTSC
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