Harmony Cart title screen distortion, then nothing

[Asriazh]

Hello there! In December 2022, i got a Harmony cart, but couldn't try it out until now (January of 2023) cause i first had to get a working Atari 2600 (Atari Junior rev. F PAL). Whenever I start the console with the Harmony Cart plugged in, i get greeted by this picture

Then, after a joystick button press, this:

The Tv is an LG OLED, but i tried this on two other TVs, a Samsung LCD and a Panasonic LCD and the results were exactly the same.

Regular cartridge games work flawlessly, as you can see here

I use the regular RF out of my Atari Jr. I tried reflashing the latest BIOS (1.06 PAL 50Hz) as well as an older 1.05 version. I think I got the best result with a 1.05 NTSC version or was it a 1.05 PAL 60Hz?, which was in b/w but at least i managed to get into the "Homebrew" section and selected a game, which to my surprise actually worked (Don't ask me which, lol). I used the Linux flash tool from your Github page, compiling it myself, cause your precompiled binary had outdated QT4 requirements. There were no issues, flashing the cart. I replaced all capacitors of the Atari Jr. and the voltage regulator, putting in a slightly beefier one, that can handle 1,5A instead of 1A. I also cleaned the cartridge slot and the contacts on the Harmony Cart.

Is my Harmony Cart defective? Is there anything I overlooked, that could solve this issue?

Thank You!😃

Edited January 8, 2023 by Asriazh
Forgot a few details

[+batari]

I got a similar report once and the problem was a bad TIA chip. Only a tiny part of the TIA was bad, so the games that did not use that specific feature worked fine. Something like that could also be caused by bad RAM on the RIOT, maybe even a single bit, and most games might still work. Could also be due to an incorrect startup state on the console (i.e., the console booted before the menu code was available, and jumped to an arbitrary entry point without clearing RAM.)

 

Of course there could also be a single bad bit of memory on the Harmony cart instead, so some more checking of things is a good idea.

 

I recommend trying some modern homebrews to see if any have strange issues. If any experts have any theories based on the screenshots and can suggest games to try that might also have the same graphical issues, post up!

 

 

[Asriazh]

I got a non working "Woody" light six switcher that's also PAL with socketed chips. I socketed the chips on the Atari Jr. as well after removing them to fix the "Woody", but the issue wasn't them, cause i had a totally black screen with audio and the games obviously running in the background, just nothing on screen. So I assume that the chips on that one are at least as O.K. as on the Jr. , since there was no video on the "Woody" with either TIA (Might be a trace damage i didn't discover yet). I'll swap the TIA of the "Woody" over to the Atari Jr. , then the RIOT chip and report back what will happen. Thanks!

[Asriazh]

Changing the RIOT chip did nothing. Changing the TIA gave me that picture

Followed by

So I guess my PAL TIA from the Woody isn't a PAL TIA and that's why there was no video out, cause the pinouts for both TIAs are slightly different and the Woody board clearly is a PAL version, cause it had a PAL RF modulator? Also both, the Atari Jr.'s TIA and RIOT chip are marginal? Or maybe just the TIA. Tho with the probably NTSC TIA, there were still issues. So it's likely that the RIOT chip might be at fault. And even at the cleaner title screen, there was still a weird bar interrupting the firmware message.... Or it's still partially the Harmony carts fault. One thing is clear tho, my Atari Jr. 's TIA (UM6526P1) has issues. Tho the picture being cleared up it's a similar effect to what happened when I loaded a firmware that displayed the splashscreen in b/w...

Edited January 9, 2023 by Asriazh
wrong tia chipnumber

[+batari]

1 hour ago, Asriazh said:

Changing the RIOT chip did nothing. Changing the TIA gave me that picture

Followed by

So I guess my PAL TIA from the Woody isn't a PAL TIA and that's why there was no video out, cause the pinouts for both TIAs are slightly different and the Woody board clearly is a PAL version, cause it had a PAL RF modulator? Also both, the Atari Jr.'s TIA and RIOT chip are marginal? Or maybe just the TIA. Tho with the probably NTSC TIA, there were still issues. So it's likely that the RIOT chip might be at fault. And even at the cleaner title screen, there was still a weird bar interrupting the firmware message.... Or it's still partially the Harmony carts fault. One thing is clear tho, my Atari Jr. 's TIA (UM6526P1) has issues. Tho the picture being cleared up it's a similar effect to what happened when I loaded a firmware that displayed the splashscreen in b/w...

Well, the second picture indicates a loss of horizontal sync. It is not possible for a cartridge to do that so that is clearly a hardware problem. I am not sure what would cause the bars above, could be Ram in the console or Harmony, but there are some other issues with the screen that suggest hardware issues with the console. 

[Asriazh]

I guess i'll bite the bullet and buy my 3rd Atari 2600 then *lol*. Third time's the charm, right? Or whatever. At least Atari Jr.s are cheaper than buying a new TIA and possibly RIOT chip *sighs* Wish me luck, I need it.

[Asriazh]

I found an interesting blogpost from someone who rebuild the atari 2600 circuitry on a breadboard:

Quote

One thing that bothered me was that the breadboard Atari would never power on cleanly - most games would just crash, and I’d have to push the 6502 reset button a couple times to make it start properly.

That happens because the 65xx family of processors doesn’t have a built-in startup circuit - when powered on, the CPU just works with whatever (usually bad) state the silicon happens to be on.

The original schematics shows a 4.7µf capacitor alongside a pull-up resistor do the job of triggering the reset once the capacitor charges, which not only ensures the proper initialization, but also gives time for the CPU to start its work at optimal power level.

I had the pull-up resistor in my drawer, but not the capacitor at that exact value. Didn’t matter: a higher value just delays power-on by a non-humanly-measurable factor, so I threw in the 100µf I had. Now the Atari turns on consistently whenever I power it. For good measure, I added the equivalent circuit for the RIOT (6532), since it also shows up on the schematics:

The blogpost entry can be found here with extra explaining pictures: https://chester.me/archives/2021/09/atari-2600-on-a-breadboard-part-vi-fixing-the-video-adding-a-joystick-and-wrapping-up/

That made be check the PCB on my current Atari Jr. . I did find the 4,7 µF capacitor for the CPU, but there was no 0.1 µF capacitor for the RIOT chip. What was more interesting though was, that i did find photos of the Atari Jr. rev. F board (which I have) that have a capacitor in parallel with R28.

Is that the missing piece, they probably deemed unnecessary on maybe later rev F voards, cause "regular" game cartridges were working just fine without it? Could this be what mine needs cause on fringe cases, like the Harmony Cart, it hates when its been powered on in a slightly unclean state and then shows a messed up screen?

On every 100th turn on try or so, the Harmony Cart does work, cause maybe the "turn on state" is by chance right for the Harmony to work ok?

In any case, I'll add the "missing" capacitor across the R28 resistor and see what happens. Apart from that, i'll have to wait for the Atari Jr. rev b I ordered on ebay and see what that does with the Harmony Cart

[Asriazh]

I put a 0,1 µF capacitor in parallel with the R28 resistor, like some Atari Jr.'s Rev F seem to have.

But that did nothing *lol* Well, I guess it was worth a try.

Maybe it's my imagination, but the picture of the Atari on my TV is now cleaner, more stable. At least it didn't kill anything. The new Atari Jr. Rev B is supposed to arrive on the 19th of Jan. Let's see...

[Asriazh]

My secind Atari Jr. , This time a Rev. B, arrived early today.

But unfortunately the Harmony Cart does exactly the same thing as in the last Atari Jr. Rev F.

Both original games i have (Berzerk PAL, Demon Attack NTSC) still work just fine, in the Atari Jr. Rev B version too, just a tiny bit less clear, cause i didn't do any recaping yet.

That's the Harmony Cart, trying to do anything:

Eventually, every blue moon, I see text. but further down folders, reaching the 2nd or 3rd subfolder level, even with text visible, the cart jumps back to the previous folder.

I also tried out a different micro SD card with just 8gb, formatted to FAT32. Same result.

I fear the Harmony Cart is defective.

There's one thing though that could complicate things... My boyfriend gave me the Harmony Cart as a Christmas present, so he bought the Harmony Cart. We also did that in America - I live in Germany. What can we do here? I hope we can find a solution everyone can be happy with. If needed, I can send you my boyfriends name and address. Thank you!

[Asriazh]

I thought about this some more. Is it possible, that the Harmony Cart creates a signal that are hard to deal with for a PAL RF modulator and because of that there's a loss of sync most of the time? That could also explain why NTSC BIOSes for the Harmony Cart have a higher chance of displaying something that looks like the regular Harmony Cart boot screen, cause the modulator can ignore color signals.

Also, if it's the RF modulator in combination with the signal the Harmony Cart "creates", would it make sense to either do a composite or S-Video mod, to circumvent the audio and video signal being handled by the RF modulator at all? I could grab the video signal directly from the CB4050 and avoid any extra influences.

A recommended step?

[+Atari2600PAL]

My Harmony cart works with all my UK PAL units - 2 off Heavy using RF, a light and a Vader with AV mods, if that adds any info

 

Menu seems clearer on RF units, but stable and legible on all 4

 

EDIT: I have updated it to the 106 PAL 50 firmware though, and I don’t think it’s an encore if that makes a difference 

Edited January 13, 2023 by Atari2600PAL

[+batari]

If there is any RF interference from the cart it would definitely not be strong enough to cause the signal to lose sync.

 

This has been a fairly difficult issue to diagnose because it appears there may be issues with the first two consoles, and each appears to have a different issue, so we could not be sure until you got that third console. I assume that this third console is working correctly.

 

I will send another Harmony cart to your address in Germany.

[Asriazh]

I just wanted to report that the replacement Harmony Cart arrived safely and is working normally, without any glitches. All games i tried so far loaded and played fine. Yay! Thank You very much for a problem free replacement of my original, now proven faulty Cart!

It has the NTSC firmware on but i think i won't flash it to the PAL version *lol* The menu shows up in b/w but thats no big deal. PAL games run with colors. So, better not risk it, hahaha.