H5B1 RGB2HDMI showing red only

[nizmow]

Hi all, I’m fairly new to the Atari scene. Had an ST as a teenager and just this week have acquired an H5B1 system from a gentleman in Queensland. It has an RGB2HDMI setup, some kind of riser card and a daughterboard with a ribbon cable. I also have an RGB2HDMI unit preconfigured. See attachments for a photo.

I had two issues, one was the Pi back feeding power into the ST! It was running with the Pi as a power source. I fixed this by just finding 5V and cutting it, all good.

Secondly, initially it worked fine but at some point the output went all red, with occasional odd looking bits of interference. At some point I had it on and was messing with the floppy power and it seemed to go colour for a while, but not long. I’ve tried wiggling chips but nothing seems to help. Anyone have any ideas where to start?

Thanks!

IMG_9728.jpeg (693.39 KiB) Viewed 2231 times

[nizmow]

I should also note: I have re-seated the shifter chip in the daughterboard, and mono (of course) works fine! I’m worried I’ve busted the shifter with that reverse voltage.

[kodak80]

The RGB2HDMI external adapter usually gets 5V from the Atari via the ribbon cable. It's one of the pins on the Shifter adapter through the ribbon cable. You just need to plug in the HDMI cable from your monitor and wait for the device to power up. If you fed 5v from the Pico into the Atari then this won't have been good.

Might be worth reading this information:
https://github.com/hoglet67/RGBtoHDMI

The standard 13 pin video socket should also work alongside the RGB2HDMI and outputs the same screen. You would need a compatible monitor and a ST2VGA adapter.

You have an original Exxos IDE and dual TOS adapter in there. This is the one designed before TruIDE.

I would recommend removing and re-seating all socketed chips, especially if this has been shipped from the previous owner.

Your RGB2HDMI shifter adapter is the older one so keep this in mind if you choose to update things. Newer adapters also have the blank input from the Atari as well.

Oh and FYI, I was the one who built the H5B1 you bought. Happy to help if you are local. I haven't done much with the RGB2HDMI in a while and am very rusty on this.

[Darklord]

"The standard 13 pin video socket should also work alongside the RGB2HDMI and outputs the same screen. You would need a compatible monitor and a ST2VGA adapter."

I think this is a very good idea. When I was installing the RGB2HDMI mod in my STacy, I used an external SC1224
monitor so I could compare.

It allowed me to separate whether something was happening (or not) from the ST itself or from the RGB2HDMI
mod.

[nizmow]

I wondered if I’d run into the builder! Thanks, looks like a great job! Yes, I messed up with the power a bit. Didn’t seem to be running without USB so I put it on, ended up switching the ST off and it kept going. Measured 4.1V on the 5V rail, whoops! Unplugged and realised my error. In theory it should be okay, in reality who knows.

I’ve been doing some investigation. Bad connections or dry joints seems unlikely as the red output is pure red, I doubt we would get bad connections on all six green and blue channels but maybe I am misunderstanding. Mono is perfectly white, but my understanding is the it uses a different signal. There are some cheap shifters on ebay which I bought so we’ll see if I busted the chip. The other option is the problem is on the Pi end, who knows. I’ll read the docs and see what I can trouble shoot.

Also waiting on a PLCC puller to resocket those with some contact cleaner without cracking the sockets. I’ve done the DIPs.

Sadly I have no 15KHz screen except for a composite monitor. I’ll see whether I can pull a composite feed, my memory of the ST is hazy.

Also I’m in Sydney, the machine has travelled far.