Getting an Interton VC 4000 functional in the US

[no attack]

I know several of you have functioning Interton VC 4000s that you play on modern NTSC sets. I'm getting one shipped from Germany as we speak, and I was looking for advice on what I needed. From what I understand, I need:

 

+ A power transformer to convert the 220V signal to the American standard.

 

+ Some means to convert the PAL signal to NTSC.

 

The transformer is straightforward, though I was hoping someone could suggest the maximum wattage I needed.

 

For signal conversion, someone suggested the Orei XD-1190 PAL HDMI/RCA to NTSC HDMI Converter, though it appears to only support signal resolutions as low as 480i, and I don't know the VC's output. (I also don't necessarily need an upscaler.)

 

Any suggestions are welcome, either for display on CRT or a modern HDTV. I'd also love any suggestions for multi-carts or other add-ons—I'd eventually like to run my own code on this thing.

 

Lastly, if anyone has a manual scan for the system (not its games or hardware clones), I'd appreciate a link. I can't seem to find one online.

 

Thanks!

[carlsson]

The system natively outputs an antenna signal that can be tricky to sync to even on a modern PAL TV. I've had most of luck using a late 1980's TV. It supposedly is possible to modify, or at least the Grundig (and French sold Interton) model to get RGB. I can't comment on the signal, but would think it is 240p like most other older systems.

 

The power supply is rated for 15VAC 230 mA + 9VAC 600 mA, which equals just below 9VA. Thus you don't need a particularly strong step-up converter for this console alone.

 

Edit: There seems to be a couple different models with varying daughter boards. All boards have in common that you can get PAL composite video + audio from the leads going into the RF modulator on the back side. To get RGB, you may need to build a daughter board of your own. Here is a thread in German with pics on how to make the simple composite video mod, and that the results seem to be good enough. I haven't tried this myself, but will probably have a go.

https://circuit-board.de/forum/index.php/Thread/4486-Interton-VC4000-AV-Mod/?pageNo=1

Edited January 20, 2017 by carlsson

[alex_79]

It outputs a progressive signal like all the consoles and computers of the era, which, using today digital TVs notation would be called "288p" (240p is the 60Hz equivalent).

All VC4000 and clones consoles can be modded to output RGB. It just takes a couple of logic ICs to combine 5 digital outputs from the video chips (the signetics 2636 and 2621) to obtain digital TTL RGB and SYNC signals, which can then be adjusted to levels suitable for analog SCART RGB (the simplest method for that only requires some resistors).

On PAL models you can also easily get composite before the rf mosulator as noted by carlsson.

As for the manual, I don't think one exists. The instructions are printed on the back of the box:

 

Also game manuals are part of the boxes:

 

Edited January 21, 2017 by alex_79

[no attack]

Thanks for the input (err, output), everyone!

 

carlsson, if you do end up modding your console, please post back here—I'd love to see the results.

[the_crayon_king]

I know several of you have functioning Interton VC 4000s that you play on modern NTSC sets. I'm getting one shipped from Germany as we speak, and I was looking for advice on what I needed. From what I understand, I need:

 

+ A power transformer to convert the 220V signal to the American standard.

 

+ Some means to convert the PAL signal to NTSC.

 

The transformer is straightforward, though I was hoping someone could suggest the maximum wattage I needed.

 

For signal conversion, someone suggested the Orei XD-1190 PAL HDMI/RCA to NTSC HDMI Converter, though it appears to only support signal resolutions as low as 480i, and I don't know the VC's output. (I also don't necessarily need an upscaler.)

 

Any suggestions are welcome, either for display on CRT or a modern HDTV. I'd also love any suggestions for multi-carts or other add-ons—I'd eventually like to run my own code on this thing.

 

Lastly, if anyone has a manual scan for the system (not its games or hardware clones), I'd appreciate a link. I can't seem to find one online.

 

Thanks!

 

You say "A power transformer to convert the 220V signal to the American standard" but you need the exact opposite of that.

 

Anyway I wouldn't even do that just find an US AC adapter that puts out the same specs as what the console does (you can figure this out by reading the back of the stock AC assuming it comes with one). (this is what I did with my GX4000).

 

If this console is functionally the same as the Arcadia 2001 an A/V or RGB mod should be possible.

A video scaler will probably have much less issues getting the signal in line with what your TV will accept (if using something besides RF).

Another method would be to try running the RF video through a VCR.

 

For the price of that RF to HDMI converter you could deff get this console modded and probably afford a proper AC as well.

[GroovyBee]

If this console is functionally the same as the Arcadia 2001 an A/V or RGB mod should be possible.ord a proper AC as well.

Its a "clone" belonging to the Radofin 1292 family and not an Arcadia 2001 clone.

[alex_79]

Anyway I wouldn't even do that just find an US AC adapter that puts out the same specs as what the console does (you can figure this out by reading the back of the stock AC assuming it comes with one). (this is what I did with my GX4000).

The VC4000 power supply ouptuts 2 voltages and uses a proprietary connector. It's unlikely that you can find a direct replacement, so, unless you have some electronic skills to build it yourself, the power converter might be the easier solution. I agree that in other cases (standard plugs and single voltage) replacing the power adapter is easier (and cheaper).

 

If this console is functionally the same as the Arcadia 2001 an A/V or RGB mod should be possible.

It is not the same as the Arcadia 2001 (it's not software compatible and it uses a previous, less powerful video chip). But it outputs the same type of signals so the mod would be similar.

[the_crayon_king]

The VC4000 power supply ouptuts 2 voltages and uses a proprietary connector. It's unlikely that you can find a direct replacement, so, unless you have some electronic skills to build it yourself, the power converter might be the easier solution. I agree that in other cases (standard plugs and single voltage) replacing the power adapter is easier (and cheaper).

 

It is not the same as the Arcadia 2001 (it's not software compatible and it uses a previous, less powerful video chip). But it outputs the same type of signals so the mod would be similar.

 

I was initially under the impression that this was related to the Arcadia 2001 (specifically a clone). They do look VERY similar.

Also I didn't see anyone's posts besides the OP (I dunno why).

 

Do you have more info on the RGB/AV mod and/or the schematics for the PCB of the console ?

What is confusing me I guess is the digital RGB part, would this digital RGB be like the 3DO's digital RGB ?

[alex_79]

I'm not familiar with the 3DO.

With digital RGB I mean that the output has TTL levels for R, G, B and Sync (like on the BCC micro computer). That is, each of these signals is either "off" (0v) or "on" (+5V). These signal are not directly available from the video chip, but they can be obtained with a couple of logic ICs. I have to search my notes, but it shouldn't be difficult to figure out how to combine the available signals by looking at the "GRUNDIG Super Play Computer 4000" schematics (which was a version of the VC4000 with a proprietary RGB plug compatible with some Grundig TVs of the era)

You'll find schematics of the Interton VC4000 and Grundig SPC4000 here:

https://amigan.yatho.com/

[the_crayon_king]

I'm not familiar with the 3DO.

With digital RGB I mean that the output has TTL levels for R, G, B and Sync (like on the BCC micro computer). That is, each of these signals is either "off" (0v) or "on" (+5V). These signal are not directly available from the video chip, but they can be obtained with a couple of logic ICs. I have to search my notes, but it shouldn't be difficult to figure out how to combine the available signals by looking at the "GRUNDIG Super Play Computer 4000" schematics (which was a version of the VC4000 with a proprietary RGB plug compatible with some Grundig TVs of the era)

You'll find schematics of the Interton VC4000 and Grundig SPC4000 here:

https://amigan.yatho.com/

 

Thanks so much.

Ok so here is what I was looking for (found from your source): http://i.imgur.com/qC1n7Rc.jpg

 

So out of the NE549 you could tap A/V there (C Video).

 

Here is the thing you mentioned about the RGB:

http://i.imgur.com/q5MVRTK.png.

 

I can work off of that and maybe make a post on this in the future.

What would be needed from here would be an IC(s) with the gates listed on the picture (may be listed on that page)

Then run that through a video amp (probably the THS7374)

[carlsson]

The link to the German forum circuit-board.de I posted above, has both instructions and screenshots after the composite video mod. Those look promising, but I understand a RGB mod would yield even better results.

 

And yes, as I wrote above the PSU has 9VAC + 15VAC (some sources quote this as 8.5VAC + 15VAC, others might go on 9VAC + 16VAC so there could be small variations) with a custom connector. However inside it seems to have the usual diodes and regulators to get DC voltages. I think someone in the linked thread wrote about this too, that internally you might power it with 5VDC + 12VDC if you do a serious mod. I don't know how much chopping up the OP wants to do, if the system is obtained as much for collection as for playing.

[alex_79]

PAL units use either a TEA1002 (PAL encoder) or a bunch of discrete components and logic gates to create the PAL composite signal which is then fed into the RF modulator. I haven't tried it myself, but apparently the composite signal before the modulator works without amplification, so you can just connect it to the RCA plug and that's it. PAL composite signal is not generated on the SECAM models (and the Grundig too).

By looking at the schematic of the Grundig model, you can see how the digital outputs of the 2636 and 2621 chips are combined:
Each of the 3 color bits are EOR-ed (Exclusive OR) with the "Object/Score" signal and the result are then AND-ed with the inverted CBLNK signal to get the TTL R,G and B.

The same signal combination can be done with a couple of logic ICs (a 7486 Quad EOR gate and a 7408 quad AND gate).

The resulting TTL RGB signals can then be converted to levels suitable for SCART with a few resistors, like shown in this page about the BBC micro:


So this is the simple RGB mod I intendeed to do on my console:
VC4000_RGB.pdf

When the console arrived, though, it turned out being the SECAM model, which has a daughter board that generates the SECAM signal and modulates it. By tracing part of this board, I found that I could just tap the TTL RGB signals from there with little modifications, saving me the hassle to build the above circuit on a breadboard.

The signals are already on the daughter board, but they're inverted. The simple modification consists in moving a few jumpers to bypass an inverter gate and to isolate the RGB signals from the following SECAM encoding circuitry that I didn't need anymore. The I just connected those signals to the SCART plug using the resistors as in the above diagram. It works perfectly! (you can see the results here)

 

(A=audio, S=Sync)

Note to all: I'm not expert in electronics, so use the above info at your own risk!

[carlsson]

Yup, the voltage divider to convert TTL to analog levels is something I've done a couple of times, mainly with Beebs but also other systems. The BBC has about 3.8V on the nominal 5V outputs IIRC, so size of resistors may need to vary depending on signal strength but generally anything in the range of 200-500 Ohm seems OK - the higher resistance, the darker colours you'll get on the TV.

 

By the way, shouldn't both the 7486 and 7408 have their VCC (5V) and GND pins connected as well, or is that understood without pointing it out?

Edited January 26, 2017 by carlsson

[alex_79]

Yes, power and ground connection of ICs are implied to simplify the schematics. Also (not the case in these examples) if there are unused gates, their inputs should usually be connected to a known state (+5V, gnd, or some other signal) and not left floating as it can cause erratic behaviour when using "HC" or "HCT" series of ICs.

Edited January 26, 2017 by alex_79

[the_crayon_king]

Yes, power and ground connection of ICs are implied to simplify the schematics. Also (not the case in these examples) if there are unused gates, their inputs should usually be connected to a known state (+5V, gnd, or some other signal) and not left floating as it can cause erratic behaviour when using "HC" or "HCT" series of ICs.

 

Three questions:

What does using both legs of an AND gate accomplish; I mean is that a way to buffer a signal or what ?

Also is that XOR gate on the CBlank signal work as an inverter when one of the inputs is locked as high ?

 

 

Lastly shouldn't there be a 75 ohm impedance matching resistor on the outputs ?

[alex_79]

What does using both legs of an AND gate accomplish; I mean is that a way to buffer a signal or what ?

Yes, it's just a buffer (and a way to ensure that the inputs of the otherwise unused 4th "AND" gate aren't left flaoting, which would cause problems if using 74HCxx or 74HCTxx parts)

 

Also is that XOR gate on the CBlank signal work as an inverter when one of the inputs is locked as high ?

Yes.

A EOR 1 = NOT A

 

Lastly shouldn't there be a 75 ohm impedance matching resistor on the outputs ?

Not in this ciruit. The resistors in series with the outputs aren't a "proper" method of adjusting the level, but more one that's easy to implement and works (most of the time). They are supposed to form a voltage divider together with the 75ohm termination inside the TV in order to reduce the voltage to a suitable level.

Edited January 26, 2017 by alex_79

[the_crayon_king]

Yes, it's just a buffer (and a way to ensure that the inputs of the otherwise unused 4th "AND" gate aren't left flaoting, which would cause problems if using 74HCxx or 74HCTxx parts)

 

Yes.

A EOR 1 = NOT A

 

Not in this ciruit. The resistors in series with the outputs aren't a "proper" method of adjusting the level, but more one that's easy to implement and works (most of the time). They are supposed to form a voltage divider together with the 75ohm termination inside the TV in order to reduce the voltage to a suitable level.

 

Someone should do this I wanna see the end result. I don't have the console to try it on...

 

You could lower the output voltages and then drive them with a THS7374 (I would only do that if the video isn't good just doing straight into the TV)

This would allow you to get the proper resistances.

Or maybe just use a transistor I think that is what is going on in the one picture.

 

This may also benefit from DC blocking caps but IDK.

Using logic gates to get video is not something I really know enough about.

Edited January 27, 2017 by the_crayon_king

[ubersaurus]

I'm interested in getting one of these to run on a PVM. Aside from modding it through SCART, I could probably try running RF through a demodulator - is the EU channel 3 different from the US one like the Japanese channel 3 is?

[carlsson]

A little different. Channel 3 on NTSC should be 60-66 MHz, while channel 3 in the UK was 56.75 MHz and 55.25 MHz in Western Europe, except for France where it was 56.15 MHz in system E and 60.50 MHz in System L.

 

https://en.wikipedia.org/wiki/Television_channel_frequencies

 

But if it is dead easy to get a PAL composite video signal from modding it, you wouldn't need a RF demodulator. Getting RGB required a bit more complicated circuit as indicated above, but if you'd be happy with a demodulated RF signal, you'll likely be overjoyed with a composite signal.

[lazzeri]

I´ve already bothered you guys with that (especially Carlsson! ), but since I´m a complete moron with a soldering iron I´ll double check.

 

I´m deeply interested in getting an Interton and A-V´ing it. Is is really that simple? Just rip the RF box and solder 3 wires?

 

An AV is not PAL, right? That´s just for RF, AV is "universal"?

 

There´s a few Interton quite cheap on german eBay, I might risk it.

 

Thank you guys!

[alex_79]

An AV is not PAL, right? That´s just for RF, AV is "universal"?

Nope.

Composite video still has the color information encoded using the PAL, NTSC or SECAM system and also their respective framerate (50 or 60Hz) and vertical resolution.

The same applies to S-video, while Component and RGB are "universal" as regards color, but still different for framerate and vertical resolution.

 

If your TV doesn't support the signal's color encoding, you'll get a B&W image. If it doesn't support the framerate and vertical resolution, the screen will roll.

Edited February 27, 2017 by alex_79

[carlsson]

Yup, what Alex_79 said. However I find it more likely for a TV set to accept composite video input of a foreign video region than for it to accept foreign RF signals.

[lazzeri]

Thank you all once again. I´ll take my chances and import me an VC4000. It´s worth the shot.

[carlsson]

Now I have done the "simple" A/V mod on my Interton VC-4000. Unfortunately the results were not as nice as they supposedly are within Germany. It could be my soldering skills or choice of materials too.

 

On a LCD screen, I got no image at all. I was afraid the machine was toast, in particular as I had cut off the RF cord since it was designed to run along at the exact same spot where I had installed RCA connectors for the composite video and audio.

 

I switched to a trusty old CRT and got a very washed out, grey image. No colours what so ever, even after carefully adjusting the potentiometer on the board. I do get rather good audio though, and by running software from the multicart I know the console is still working as it should.

 

The German page says no amplification of the signal is required, but I'm wondering if that is the truth. There were a couple of motherboard versions too, perhaps voltage levels differ? To be sure, I soldered off all legs to the RF modulator, so it would not steal anything of the signal.

 

So right now I've got a console that displays a very washed out grey image with a bit of jitter, yet using composite video instead of RF. I'll have to troubleshoot to see where I may have gone wrong, if it is due to bad soldering, bad cables, bad connectors or that it simply is not supposed to be as easy as they made it on the other forum.

 

(And no, unfortunately this is not an April Fool's Joke)

[carlsson]

After a good night of sleep, I had another try. First I soldered in different RCA connectors on a different wire to ensure the problem would not be there. No difference in video output.

 

 

Then I looked at the two "expansion" boards on the motherboard. The smaller one is for sound, the bigger one is for video. Apparently each revision of the Interton looks different, some have these components on the main board, others have expansion boards of various sizes. Though at least a couple of the people in the other thread have a board like mine. The potentiometer that I twisted yesterday apparently is a volume control that connects to the RF modulator, so it didn't make any difference.

 

However I removed the video board and found a potentiometer called R10. I'm not sure if that is the same as the Germans call "POTI", but I carefully twisted it a bit, put the board back and tried again. Suddenly I got colours! I twisted it back to a position where I got nothing on screen, then back to grey and back to colour. However I only manage to get any image on a CRT, the LCD still doesn't detect a signal.

 

 

In order to assemble the console properly and get the cartridge to get full contact, I had to trim away some leftover glue and plastic from the RCA connectors that I have glued on the outside of the back panel. This could've been done in a nicer fashion and a bit further up to easier get the console to close, but eventually I have managed to put it all back together and get it to function.

 

So yes, the A/V mod will work but look for something to adjust whether it is called R10, POTI or something else. Be aware that the most obviously visible potentiometer is related to RF volume so that is not the one you should adjust.

 

Edit: I tried on my 40" LCD TV. It displays a very dark, but colourful image. Adjusting settings improve it a little, but an amplifier might be in order. I've got a such circuit, I'll look into instructions how to install it.

Edited April 1, 2017 by carlsson