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Connecting an Arcade PCB to a CRT TV


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I have checked out the TV and it is the same as the schematic and used though hole components. I will add the resistors etc and see how it goes. Do I need a resistor for the sync going to the composite video in?
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Just tried the TV and its got RGB but it will not sync. Tried Pandoras box and also a SMS2 with RGB out. I could see Alex Kidd title clearly for a moment but everything else is out of sync. I have looked for a service mode but have not found anything yet. Is there anything that can be tried to sync the video?
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Should be just a matter of feeding the csync through a 1K and then into the AV port.

 

The SMS2, is it just regular scart output? If so it won’t need a 1K on sync.

 

Is the Pandora’a box doing 15 kHz?

 

 

Sent from my iPhone using Aussie Arcade

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Yes I have the Csync via 1K to the Video In on the TV.

The SMS2 I will try without the 1K and see what happens.

The Pandora box is 15Khz via the JAMMA edge and does work on other 15K arcade monitors.

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Re SMS and its scart cable, it'll depend how it's wired in regards to what type of sync is output. Generally they're wired to use composite video as sync, so 0.7Vpp but some places like RGC wire them as csync which is TTL level 5Vpp - however places like RGC include a series resistor on the csync line which forms a voltage divider with the TVs 75 Ohm termination and brings it back down to 0.7Vpp.

 

In short, I don't think any further resistors will be necessary, ditch the 1K.

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I did find a service switch but pressing it just gives a horizontal line for adjustment no menu.

I also found this which I will try but it may not have sync adjustments.

https://translate.google.com/translate?hl=en&sl=ru&u=http://monitor.espec.ws/section23/topic78163.html&prev=search

Also looking at the schematic H and V sync inputs are on pins 1 and 2 of the micro, could a pot be added there?

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I think they are used so the micro controller knows when to send characters.

 

Ok I see.

 

I did get the TV to bring up a service menu by connecting Pin 28 to a 22K resistor to ground on IC101. I could not do anything, any key a press on the remote or TV would just toggle the service menu on or off.

 

Has anyone seen this?

https://www.retrorgb.com/new-crt-rgb-mod-board.html

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That thing is totally unneeded.

 

If you were able to get one device working you will be able to get others.

 

If you need to change hpos/vpos frank knows a little board that works a treat.

 

 

Sent from my iPhone using Aussie Arcade

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Yes hopefully I can get it to work with everything at some stage, but great so far with Sega consoles.

I did see the PCB a while back, it looks good.

https://www.aussiearcade.com/showthread.php/98083-Jamma-Horizontal-and-Vertical-position-adjustment-PCB

 

Also saw this interesting read on fixing sync issues

https://martin-jones.com/2014/09/16/that-syncing-feeling-classic-arcade-games-that-wont-stay-still/

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  • 1 month later...

Saw this on EEVBLOG

A Sony TV that uses a MC44002 jungle chip.

Dave injects RGB into the RGB inputs on the chip and ties the Fast Commutate pin to 5V.

I have 2 Sony TVs but they don't have that jungle chip. They are newer (BG3S, BX1S) and maybe disabled in software?

 

https://www.eevblog.com/forum/blog/eevblog-1246-dumpster-tv-to-retro-rgb-monitor-conversion/

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  • 1 month later...
  • 2 weeks later...

Saw your post here:

https://shmups.system11.org/viewtopic.php?f=6&t=60130

 

I will give a try when I get a chance. thanks.

 

Solder a 0.1" (2.54) header into the empty Teletext port. CN307.

Connect a ground wire to the Teletext ground

Connect your external RGB lines to ground via 75Ohm resistors and then have them run to the Teletext RGB ports.

Connect a line from the output of the 5V regulator (IC604) into the blanking pin (BLK) of the teletext port. I normally use a switch so I can turn off the RGB. Another option here would be to run the Scart Pin 16's blanking signal to this pin.

Take sync and sync ground into an AV port and change the input of the set to that input. I usually use an RCA AV cable of some sort.

In order to get the OSD to be less washed out you might want to experiment with adding resistors to the external RGB lines.

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  • 3 months later...
...is there a list anywhere of TVs that are known to be suitable for RGB modding?

 

The OP of the shmups RGB modding thread contains a few in the spoiler, but otherwise, no. Most sets with an OSD are suitable though, so google up the service manuals for those ones and post up either there or here for advice if you get stuck.

 

Safety first! Make sure you know how to discharge the tube if you need to.

 

 

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