Atari 130XE and SAVO wiring?

[flashjazzcat]

13 minutes ago, macsonny said:

continuity buzzes as I figure there must be some capacitors or similar in the cable?

Yeah - there are electrolytic caps inline on R, G and B. You appear to be in RGB mode, you appear to have sync, but since the colour's off I'm assuming you're missing one of more colour signals.

[macsonny]

25 minutes ago, flashjazzcat said:

That impression might be caused by the fact the plastic sleeve has been aggressively trimmed back to clear the machine's case, but the connector is certainly sitting at an odd angle.

 

The lumpy soldering on the DIN connector anchor doesn't inspire confidence either. On a SAVO board I modified with straight header pins, when I was prising the plastic frame off the existing header pins before desoldering them, a couple of pins ripped clean out of the board without damaging the vias, which was very odd indeed (suggesting that the solder itself was of quite poor consistency).

Have reflowed the DIN connector as it was a bit questionable 🙂

 

I have removed the SAVO board and tried a little more bug finding including lots of wiggling and pressure on the cable connector - didn't make a lick of difference.

 

 

[macsonny]

3 minutes ago, flashjazzcat said:

Yeah - there are electrolytic caps inline on R, G and B. You appear to be in RGB mode, you appear to have sync, but since the colour's off I'm assuming you're missing one of more colour signals.

That's what I figure too but can't work out which one as they all seem to buzz ok?

[flashjazzcat]

And you definitely have 5V on RGB CTRL?

[macsonny]

1 minute ago, flashjazzcat said:

And you definitely have 5V on RGB CTRL?

Yes. 5.077 V according to my MM.

 

I did wiggle the VBXE and noticed a flash of blue before it went back to red. I'm just checking the pins are seated correctly, etc.

[macsonny]

Interestedly if I disconnected the "G" and "B" connectors to the VBXE board, it makes zero difference to the image on the screen. Removing "R" causes the screen to go black so it looks like the :G" and "B" signals are getting from the VBXE board to the SAVO.

[flashjazzcat]

So green and blue are NOT getting through, just red. And I think in a prior photo, it looked like you had red and blue but no green.

 

[flashjazzcat]

Anyway: troubleshooting law dictates that the last thing you changed caused the problem, and it was shortening wires.

 

[macsonny]

Just now, flashjazzcat said:

Anyway: troubleshooting law dictates that the last thing you changed caused the problem, and it was shortening wires.

 

LOL - I hear you. The other law is never mess with something that isn't broke. Threw that rule well and truly out the window 🙂

 

I'll keep fault finding - I think I've narrowed it down to the VBXE rather than SAVO. Should I try flashing firmware or something like that?

 

[flashjazzcat]

10 minutes ago, macsonny said:

Should I try flashing firmware or something like that?

I tend to find that VBXE either works or doesn't, and if the core is corrupted (or the FPGA is dead), you'll get no output at all. If you do want to flash it, grab the 'Cores' file from the attachment/files tab on Lotharek's product page, extract one of the ATRs, and run FC.COM. It should pick up the hardware and show you the contents of the twelve flash ROM slots, and probably indicate that slot one is the boot bank, and that it contains FX core v1.26. There are three v126 cores on the disk image: G, R, and A. You want the 'A' (FX) one. You can flash it to an empty bank and set that bank as the boot bank if you're worried about a bad flash on the active boot bank.

 

Doubtful the flash ROM got corrupted, however. The other (rare) problem I've encountered is dry solder joints or oxidisation (these being old-stock, deprecated parts) on the FPGA itself. But before delving into that kind of rabbit-hole, it would be prudent to assume that wiring is the issue.

Edited August 9, 2023 by flashjazzcat

[Piotr D. Kaczorowski]

"Divide and conquer"...

 

It's worth determining where the problem lies. At the beginning, I would check if the signals from VBXE are being transmitted. It's most convenient to check this if you are equipped with professional equipment - e.g., an oscilloscope. If not, then if something is visible through the TV, just connect, for example, the green color signal to SAVO Green, and later test the other signals from VBXE on this channel, i.e., red and blue. You can do the same in the other direction: a working VBXE green can be checked on SAVO green, SAVO red, SAVO blue.

 

I would like to remind you that I take great care in creating SAVO boards. Please note that each board is carefully cleaned with IPA, and beforehand, each of them is subjected to tests. I use a multimeter and check continuity on two cables: Sega Saturn to Euro SCART and Sega Saturn to RCA + s-video. Every signal from the board is tested.

 

Statistically, out of about 30 boards that I assembled myself, I currently have 3 VBXE boards that require flashing or re-soldering of circuits. However, I cannot say that this is a problem only with VBXE. I also had a damaged DAC converter in one Sophia 2 board, and a colleague from the Czech Republic had the same problem with Sophia 2. I encountered damaged 64K V3 SRAM memories - where pins had to be re-soldered. This is electronics, and these things happen. It requires a bit more struggle, but satisfaction is guaranteed after some time.

 

It's worth checking the all connections with the installation instructions: http://ftp.pigwa.net/stuff/projects/SAVO/

 

 

[flashjazzcat]

39 minutes ago, Piotr D. Kaczorowski said:

Statistically, out of about 30 boards that I assembled myself, I currently have 3 VBXE boards that require flashing or re-soldering of circuits. However, I cannot say that this is a problem only with VBXE. I also had a damaged DAC converter in one Sophia 2 board, and a colleague from the Czech Republic had the same problem with Sophia 2. I encountered damaged 64K V3 SRAM memories - where pins had to be re-soldered. This is electronics, and these things happen. It requires a bit more struggle, but satisfaction is guaranteed after some time.

VBXE and Sophia are complex electronic devices. SAVO is a PCB with a connector at one end and a row of pins on the other. I suppose it would be next to impossible to assemble one that didn't work.

[macsonny]

So after a few hours of diagnostics last night I gave up. I hate going to bed having not solved a problem too !!!!

 

Decided today to completely disassemble the VBXE and SAVO. Removed all wires, and threw away all header connectors that originally came with the VBXE and SAVO. I actually found two of the header connectors were faulty - so decided to start with a fresh new set. Then rewired VBXE followed by SAVO and SUCCESS!!!! Now getting a beautiful crisp image.

 

BUT, and there is always a BUT - still back to square one with the jail bars as can be seen in the photo. The plus is I don't get a hum on the audio and the text is really sharp - just at the cost of having jail bars. Maybe I'll just have to live with them?

 

Thanks to all the assistance. My suspicion is a questionable wire/header connector was in there somewhere.

 

 

[Piotr D. Kaczorowski]

1 hour ago, flashjazzcat said:

VBXE and Sophia are complex electronic devices. SAVO is a PCB with a connector at one end and a row of pins on the other. I suppose it would be next to impossible to assemble one that didn't work.

Correct. However, I wrote what I consider to be a principle in the production of any solution. Indeed, I haven't yet found a faulty SAVO board. Nevertheless, if you solder dozens of boards in one afternoon, there might be a chip or something similar somewhere - that's what I assume. Therefore, knowing that the boards are sold not only in Poland, I check them. The next SAVO+, SAVO MAX, and HAVO (with micro HDMI output) boards are equipped with electronics. I've been testing noise removal from synchronization for three weeks now, using various voltage regulators and optoelectronic isolation that blocks returning noise, so the next versions are no longer as trivial.

[Piotr D. Kaczorowski]

@macsonny,

 

Quote

 

BUT, and there is always a BUT - still back to square one with the jail bars as can be seen in the photo. The plus is I don't get a hum on the audio and the text is really sharp - just at the cost of having jail bars. Maybe I'll just have to live with them?

 

Thanks to all the assistance. My suspicion is a questionable wire/header connector was in there somewhere.

 

 

To remove the outline around letters and the cursor, you need to disable or reduce the sharpening on your TV. Sharpening on the TV is achieved using a comb filter. The comb filter superimposes and sums the original image with images shifted in each direction, which means it improves a poor image and unfortunately slightly degrades a very good one by creating a shadow in each direction. This is exactly what you have.

 

[Piotr D. Kaczorowski]

@macsonny,

 

Pro tip:

 

This is MadTeam's site (Atari hackers' page) https://madteam.atari8.info/index.php?prod=vbxe

You can find here: https://madteam.atari8.info/vbxe/rocky_pal.7z

 

These are custom versions of VBXE cores with a gorgeous Atari-like (deep blue) palette - aka Rocky's palette. They were made by Electron (the first author of VBXE) for Mad Team members.

 

Rocky's palette looks exactly like the palette in my 600XL. However, if you want to have the NTSC version of the palette, you must use a special program or have Ultimate 1MB with a special option that allows you to change the palette right after the computer starts. 

[macsonny]

11 hours ago, Piotr D. Kaczorowski said:

@macsonny,

 

Pro tip:

 

This is MadTeam's site (Atari hackers' page) https://madteam.atari8.info/index.php?prod=vbxe

You can find here: https://madteam.atari8.info/vbxe/rocky_pal.7z

 

These are custom versions of VBXE cores with a gorgeous Atari-like (deep blue) palette - aka Rocky's palette. They were made by Electron (the first author of VBXE) for Mad Team members.

 

Rocky's palette looks exactly like the palette in my 600XL. However, if you want to have the NTSC version of the palette, you must use a special program or have Ultimate 1MB with a special option that allows you to change the palette right after the computer starts. 

Thanks for the tip!