Yet another dumb ST to VGA adaptor

[mpattonm]

Hello,

few month ago, when I have learned about 15kHz VGA monitors, I decided to replace my aging SCART connected TV with modern LCD monitor. While the circuity to switch between LOW-MED and HIGH resolution mode is trivial, yet there were no cables/boards available at that time to allow both modes, I have decided to design/build myself one from scratch. Luckily, at the same time, member ube had published his work so that inspired me to go PSB way and save myself from soldering hell.
Ube switch PCB was interesting, but I wanted something else. Something simple, truly reliable, compact, cheap and feature-wise "just working". So as I said, I have decided to design my own PCB with just basic components - 13p DIN, 15p VGA female connector and 4P2T micro switch.
And because I always order in batches, I have some spare adapters/kits left, that I am offering here for sale.

pros:
LOW/MED and HIGH resolution switch
compact - PCB size is just 31x31mm
cheap - just bare minimum of components
reliable - no sensitive parts
gold flash VGA connector for best possible and reliable connection
simple to build
optional audio out via cable pinout
can be built as bare PCB or enclosed version
does not block interfere with other ST ports
does not exceed ST case profile, even when enclosed

cons:
no other features, but VGA out and (optional) audio out

DYI kit is 9 EUR /10 USD
assembled version is +5 EUR /+6 USD
matching plastic enclosure (35x35x20mm with cutouts, black only for now) is +6 EUR /+7 USD

By the way, this supported monitor http://www.benq.com/product/monitor/bl702a is still comertially available.
Please drop me a private message, if you are interested in one of these.

credits:
Info coach http://info-coach.fr/atari/hardware
Teardown lab https://www.youtube.com/watch?v=N9xhNgCW2LQ
member UBE

[Cyprian]

nice thing.
two for me pls

both - assembled version and matching plastic enclosure

[Greenious]

Nice work!

[itaboy]

One for me... And as i am totally unable to do.anythimg with my hands, fully assembled...
very nice work btw

[mikro]

I'd take two.

[Estrayk]

One for me assembled please

[kodak80]

Two for me please, fully assembled with case.

[davemacblack]

One fully assembled with case for me, please.

Thanx, Dave

[DarkLord]

2 for me as well. One fully assembled with the case and one fully
assembled but without the case.

Thanks!

[troed]

I really really don't want to rain on the parade, but, doing this completely without resistors might work fine on some screens and not on others. When I built my own switchable cables a while back (for my Dell 2001FP) I used resistors on R,G,B (but nothing on Mono) to get good image quality.

[dhedberg]

I really really don't want to rain on the parade, but, doing this completely without resistors might work fine on some screens and not on others. When I built my own switchable cables a while back (for my Dell 2001FP) I used resistors on R,G,B (but nothing on Mono) to get good image quality.

What did the picture look like without the resistors on the R, G, B signals? Too bright? Could it not be compensated with by the monitor controls? Just curious...

[troed]

I really really don't want to rain on the parade, but, doing this completely without resistors might work fine on some screens and not on others. When I built my own switchable cables a while back (for my Dell 2001FP) I used resistors on R,G,B (but nothing on Mono) to get good image quality.

What did the picture look like without the resistors on the R, G, B signals? Too bright? Could it not be compensated with by the monitor controls? Just curious...

Yeah, washed out. The monitor could not gain the color resolution back once it was gone from it's internal AD conversion. It's surely different between different monitors, I just want to highlight that there's a reason why schematics have resistors. Ube went all the way to trimpots which might be overkill but on the other hand can't go wrong.

(I followed a schematic someone at Atariage had done, and he used a 100 Ohm resistor on mono. That, however, caused a way too dark picture on my Dell 2001FP so I ended up without)

[mpattonm]

Not to argue with anyone, but I yet have to find monitor that would require decreasing input RGB signal strength. This is actually true for TV via SCART too, in my case. Well might as well be just good luck though.

[ube]

There you go! Nice work, pretty much my first idea when I started. However I'd still have some trimpots (or at least resistors) for adjustments, I've gotten some feedback that they were useful. But if it's because of the monitor or the D/A-conversion inside the ST I don't know.

(BTW, your domain seems to be down? )

[Mrchip]

2 for me please 1 complete with case, i'm in the uk... cheers.

[mpattonm]

Since I basically sold all units I had on hand to other members here, including the one I made for myself, I will make some more. Just few, probably 5-10pcs. I am considering adding THT resistor solder pads on RGB signal tracks, with closed conection between them. So if you ever need to put some resistors on, you would simply cut the track between the solder pads and solder the resistors of your choice on.

Well I have not put my domain up (yet), its been like this for almost 2 years now. You know - priorities

[ccarl84]

Good evening,

I am interested in a complete kit.
How do you know if a screen is multisynchro?

Thank you

ccarl84

[hellraiser]

Interested in one assembled

[ScreamingJoeBlade]

WOW - If you are still making them I would love 2 fully assembled.

[wongck]

If still available I will get one for my STFM.

[BoNuS]

I would like 2 assembled with casing please, let me know how to proceed !

[Cyprian]

mpattonm, got it. Thanks.
works ok for me, I'll publish some photos later

[Cyprian]

My main Toshiba TV doesn't accept ST Low over VGA.
Below screenshots from my other small lcd tv/monitor. It has limited scaling option therefore I'm not able remove Moire patterns:

IMAG0636.jpg

Below a screen generated by my small test application "KOLORY.TOS". Every color should have 16 steps to black:

IMAG0635.jpg

[mpattonm]

New batch (and actually new, slightly modified ,revision) is beeing manufactured, those who were waiting for it will be notified via PM shortly.