CPC2VGA

[Bryce]

Here you can buy it in small and large quantities:

in theory yes, in practice it's 18€ for shipping which makes it no longer feasible.

Thruhole is to large for this connector.
 

I found a very simple circuit which has been reported to work in a similar context. If that works for the CPC, it should fit onto a PCB. Even including a 5.5/2.1mm connector. The 5V from the power supply go into the adapter and from there a short power cable into the CPC.

 

That's a great usage of PCB real estate. By putting the VGA and CPC connector on the bottom side you've seriously shrunk the size of the board. Going SMD would shrink it further, but that takes away from the Retro look, so I wouldn't go that far.

Bryce.

[dodogildo]

I tried this setup but it didn't work with my 15khz monitor (BENQ BL912)

I double checked my makeshift cable with a multimeter but it was all good.
I don't know if it's the Csync problem or not.

[SerErris]

Acording to source on the net, it requires HSync and Vsync, where HSync can be just forwarded CSync, but VSync is something you need to derive from CSync.

[SerErris]

Here you can buy it in small and large quantities:

in theory yes, in practice it's 18€ for shipping which makes it no longer feasible.

Thruhole is to large for this connector.
 

I found a very simple circuit which has been reported to work in a similar context. If that works for the CPC, it should fit onto a PCB. Even including a 5.5/2.1mm connector. The 5V from the power supply go into the adapter and from there a short power cable into the CPC.

 

Looking at the picture I think you are missing a decoupling cap on the 1881 ... It is general good practice to decouple any IC to ensure stable operation. 

Another idea is that you can put a male barrel power connector to the CPC on the same board next to the 6-pin DIN connector. So you plug in both and plug in power from the monitor into the I am not sure if a vertical barrel connector exists to solder on - but that would be great. However you would need different adapters for 464 and 6128 then.  On first glance, those were not in the same position.

[eto]

Looking at the picture I think you are missing a decoupling cap on the 1881 ... It is general good practice to decouple any IC to ensure stable operation. 

You mean between VCC and GND? true... I forgot that.

Another idea is that you can put a male barrel power connector to the CPC on the same board next to the 6-pin DIN connector. So you plug in both and plug in power from the monitor into the I am not sure if a vertical barrel connector exists to solder on - but that would be great. However you would need different adapters for 464 and 6128 then.  On first glance, those were not in the same position.

That was my first idea when I looked at the back of the 6128 and the 464. But I could not find a vertical barrel connector that could be soldered on the PCB. For now, my idea is to have the 5V and GND on the PCB so you can solder a short cable with a barrel plug. The 5V from the power supply will go into the female barrel connector on the PCB (top right corner) and from the 5V/GND on the PCB the connection will then go into the CPC. I probably need bigger traces but there should be enough space on the PCB to make that work. 

[SerErris]

Maybe something like this, but most likely the plastic part is to long:

[eto]

Maybe something like this, but most likely the plastic part is to long:

definitely too long.

I have just ordered two LM1881 and will test the set-up in a breadboard as soon as possible (but might be after Christmas). 

[SerErris]

will definitely work  

[McArti0]

CRT Philips 109s has VESA standard and read Csync from Amstrad.

ps. this is Mode 1, 160x200. possible 200x480. CRT recognize min. 28.5kHz from Amstrad.

[GUNHED]

Hi eto! Cool project! Such an adaptor is a great idea. Saving space and providing more stability compared to some self-soldered cable. 

[eto]

Such an adaptor is a great idea.

I'm not the one who had the idea in the first place. It's just that existing adapters are flawed and either expensive or unavailable. Let's hope it works and then I can add it to the Wiki. 

[eto]

I finally had time to test it - and it was successful. With a LM1881 the NEC now outputs the CPCs display signal.

I will now order the PCBs and test them next.

[ervin]

Does this work well with games that use CRTC tricks for smooth scrolling?
(Like Ghosts n Goblins)

[eto]

Does this work well with games that use CRTC tricks for smooth scrolling?
(Like Ghosts n Goblins)

The adapter does not do anything to the signal (except for splitting it), it totally depends on the monitor (or converter/scan doubler) what works and what is unplayable.

I did some tests in the past and the screens I had that accept the CPC signal directly also worked well with most (!) games including Ghosts'n Goblins. But e.g. Relentless didn't work on a single configuration. What I found interesting: Super Edge Grinder was unplayable but Edge Grinder was perfectly smooth.

It's a different story with scan doublers or HDMI converters. Many of them have issues with Ghost's n Goblins. That can also be the case for TVs with RGB input as some seem also to have a RGB2HDMI converter built-in, which are bad for screen lag and can have issues with CRTC tricks.

I'll do some tests with the NEC monitor as I could not test it in the past and at least on the Amiga and Atari ST the NEC seems to be one of the best 15kHz compatible TFTs.

[eto]

The PCBs finally arrived - and of course I made some minor and one major mistake ;-) (I switched 5V and GND... argl)

Anyway - it was good enough to see that it works and to hopefully make the final version of the circuit. Btw: The 75Ohm resistors in the RGB lines might not be necessary. In that case, they can just be bridged. I'll keep them in the PCB as it's easy to bridge them if not needed and much harder to add if required.

A SMD version would not save much space as the connectors will still stay huge and need some space next to each other with the empty space just being enough for through-hole components.

The circuit is a 1:1 copy of the original circuit in the LM1881 datasheet, no changes needed to be applied.

[robcfg]

I'd love to know how that works with a VGA to HDMI converter, as it would make my CPC life easier.

Is it easy to get the power cable splitter or do we have to build it ourselves?

Other than that, looking good! (aka I'd like to try it   )

[Bryce]

I'd love to know how that works with a VGA to HDMI converter, as it would make my CPC life easier.

Is it easy to get the power cable splitter or do we have to build it ourselves?

Other than that, looking good! (aka I'd like to try it  )

Most likely it wouldn't work at all. It's extremely unlikely that any of those converters recognise anything below 31.469kHz.

Bryce.
 

[eto]

Is it easy to get the power cable splitter or do we have to build it ourselves?

You can get "DC splitter cables" for a few bucks on Amazon. 

It's also possible to get the power from this PCB. There are pads to pass through the power from the jack. You can solder two wires to those pads and attach a power connector. This power connector goes into the CPC and the 5V cable from the monitor goes into the power jack on the PCB. 

Btw: I'm already thinking about a solution that plugs into the CPC including a power connector. But that will also require a 3d printed case... not sure if it's robust enough. 

[rexbeng]

What I found interesting: Super Edge Grinder was unplayable but Edge Grinder was perfectly smooth.

SEG has an addition in comparison to EG. At the end of the stage, the scrolling stops to host the boss fight. Perhaps this is what results in the drastic difference you are getting, but I am not sure. Perhaps @Axelay could shed some light?

[Axelay]

What I found interesting: Super Edge Grinder was unplayable but Edge Grinder was perfectly smooth.

SEG has an addition in comparison to EG. At the end of the stage, the scrolling stops to host the boss fight. Perhaps this is what results in the drastic difference you are getting, but I am not sure. Perhaps @Axelay could shed some light?

Sorry, no idea.  It was quite a while ago now, but I thought the split code was unchanged between them so I'm not sure why they'd be behaving differently.

[nikos_a]

I have the CPC2VGA adapter from Edu Arana. Works really well with a Microvitech multiscan CRT monitor. I would happily get one of these @eto if it includes a 3D printed case. I love Edu's adapter but all those exposed PCB freak me out a bit. BTW, @eto, if you want me to check anything on the adapter I have or I can help somehow, give me a shout.

[dodogildo]

I have the CPC2VGA adapter from Edu Arana.

Wow! Thanks to you I googled and discovered their store. What a great selection of hardware!!
I've been seeking CSync2HVSync – Sync converter for a while, with no luck.
Cheers

[eto]

Wow! Thanks to you I googled and discovered their store. What a great selection of hardware!!
I've been seeking CSync2HVSync – Sync converter for a while, with no luck.
Cheers

The one from Arananet seems to require that the monitor provides the power. If there is no power coming from the monitor (which e.g. the NEC 1970NXp does not do), the adapter will not split the sync signal. 

[dodogildo]

The one from Arananet seems to require that the monitor provides the power. If there is no power coming from the monitor (which e.g. the NEC 1970NXp does not do), the adapter will not split the sync signal. 

My BENQ 912 is listed as having "full support" for "unpowered adapters" on this list, as opposed to NEC 1970NXp:
http://15khz.wikidot.com/

I hope Arananet adapter will work, if not I'll keep using my RGBtoHDMI or OSSC as always.

[eto]

The BenQ accepts composite sync. Then any passive adapter will work too.