samtron mini monitor problem

TheShanMan

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I've done the rgb/sync mods to make a 5" samtron interface with an arcade pcb and it more or less works, but it makes kind of a buzzing noise and has a visual artifact that I am guessing is directly related (the white lines that are bunched up on the right). I thought maybe the anode wasn't connected well, but I double checked it and it's fine. I also thought it might be the screen control being too high, but I adjusted that and the visual issue remains even when the whole picture is dim.

I don't imagine there are many samtron experts here, but do these symptoms mean anything generally to anyone? Any ideas what it might indicate or what the source of the problem might be?

I have several of these monitors that I was planning to mod for some friends, so once I get around to building those I guess I'll see if it's something wrong with how I'm doing the mod or if it is an issue with just that one monitor, but nevertheless I'd like to figure out what the problem is and get it fixed.

I tried to capture the buzzing sound on video but it just isn't loud enough, even if I put the camera inside the monitor box (frame). If there are no other sounds in the room (games off) I can hear it across the room though, so it definitely isn't "normal".

 
Probably the stupid ones (this one is the main one I followed). I wasn't aware of your instructions but I would love to have them. I have 3 more monitors that haven't been modded yet so I'd be happy to use your approach on those, and then undo the work on this first one to do it your way. Would you share your instructions with me please, or tell me where to find them? Thanks!
 
Whose instructions did you follow? Mine that cost $0.15 or the stupid ones that have been floating around the net for years that cost about $20 to do?

I bought 3 of these monitors but never got around to modifying them for mini arcade projects. Any instructions for this would be awesome.

Where are your instructions please.
Do you have a parts list w/ links to where you go them?

thanks again!
 
Bump. Mark??? Help us out here! Can we get those instructions please? I tried searching around here and google for info you may have posted and came up dry. Let us know if you will be able to dig up the details please. Thanks!
 
Any luck finding the cheap instructions? I have a couple of these that I should do something with at some point.
 
Monitor Sounds

I have built three of these and each makes a noise. But if you adjust one of the pots on the chassis (I dont recall which) the noise can be lessened but I have not been able to get it to go away. I do get it to where it is barely noticeable.

The last one I built I added the contrast pot, and it helps when adjusting the screen control and removing the white lines.

Overall I like the monitor and building the converter board is pretty simple and straight forward.



I've done the rgb/sync mods to make a 5" samtron interface with an arcade pcb and it more or less works, but it makes kind of a buzzing noise and has a visual artifact that I am guessing is directly related (the white lines that are bunched up on the right). I thought maybe the anode wasn't connected well, but I double checked it and it's fine. I also thought it might be the screen control being too high, but I adjusted that and the visual issue remains even when the whole picture is dim.

I don't imagine there are many samtron experts here, but do these symptoms mean anything generally to anyone? Any ideas what it might indicate or what the source of the problem might be?

I have several of these monitors that I was planning to mod for some friends, so once I get around to building those I guess I'll see if it's something wrong with how I'm doing the mod or if it is an issue with just that one monitor, but nevertheless I'd like to figure out what the problem is and get it fixed.

I tried to capture the buzzing sound on video but it just isn't loud enough, even if I put the camera inside the monitor box (frame). If there are no other sounds in the room (games off) I can hear it across the room though, so it definitely isn't "normal".

 
curious...

I've done the rgb/sync mods to make a 5" samtron interface with an arcade pcb and it more or less works, but it makes kind of a buzzing noise and has a visual artifact that I am guessing is directly related (the white lines that are bunched up on the right)...

ShanMan, did you ever find a solution?

Bump. Mark??? Help us out here! Can we get those instructions please? I tried searching around here and google for info you may have posted and came up dry. Let us know if you will be able to dig up the details please. Thanks!

Mark's 15¢ solution seems infinitely preferable to spending $15. In fact, I'd estimate the cost closer to 9¢ for two resistors and a small ceramic cap. :) However, the instructions presume you already have access to separated horizontal and vertical sync lines. The info is on his site, you'll just have to search for them. They are in the bottom of a locked filing cabinet stuck in a disused lavatory. "But the plans were on display!"

excerpt from Mark's instructions if he doesn't mind me quoting him said:
Wire -CSync to open pad at J16
Wire +Csync to CN101 pin 2
Wire open pad at R119 to CN101 pin 4 (+vsync)
Wire IC103 pin 1 to CN101 pin 1 (+h/csync)

Most folks will still need a sync stripper, or a lot of experience/knowledge to find separated sync before it gets combined before the JAMMA connector. In this case, the Mr. Do manual shows how (last page) to modify the output for separate vert. and horizontal sync but it still requires that you wire up a couple hex inverters plus a few resistors.

Point is, whether you spend $2, or $20, your time is still the biggest expense here.


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Judge for yourself the value of this information

The 15¢ solution was uncovered on these forums already so I think it's safe to share...

Here's the big reveal. Woo.

It's not a solution for most arcade PCBs. Two resistors and a cap will not allow composite sync to be used with the Samtron CRT.
 
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