OJ’s projects…usually breaking stuff.

[olivier.jan]

Busy day breaking things again.
While testing a bit more the USB power supply, my keyboard suddenly stopped working, a few reboots later still nothing. First thought : “my PSU fried something”.
Tried another keyboard, still nothing working, tried original keyboard with another ST, working, so not the keyboard.
Started swapping 6850 with known good ones, nothing. After a while the Phoenix stopped booting when a 6850 was inserted but booted fine (without a working keyboard though) when no 6850 is in the socket.

So now I suspect the sockets, tried to change both just to realize that out of the hundreds of sockets I have, there are no 24 pins Hopefully Amazon will deliver some 24 pins sockets tomorrow.

While troubleshooting, my Medusa scan doubler stopped working all of a sudden. Not even possible to connect to its console via USB. Luckily Lotharek answered my emails quickly and after a Factory reset and a firmware flash, it’s working again although the integrated OLED screen shows no sign of life.

Looked through all my drawers to find that all my OLED screens are I2C and not SPI like the one needed for Medusa, Amazon purchase again.

If I was a conspiracy aficionado, I would think Amazon is behind all that

Anyway, if everything goes well I will have everything fixed over the long weekend ahead. I just hope the keyboard issue isn’t related to a short in the MB or a broken trace in the internal layers.

[exxos]

Your luck sounds as bad as mine

[olivier.jan]

Bit luckier today. I fixed the Medusa with a new OLED screen and tested the new USB-C PSU for a while.
Overall, it's much better than I initially expected, no power spike when turning on or off, and a very low ripple inside the ST (a Phoenix H5C), just 60mV peak to peak. Only small issue, the voltage under load is 4.94V, not a proper 5V, I guess I will need to slightly adjust some resistors.

In terms of temperature, only one component is heating a bit, but never went above 55C while running through multiple Gembench tests, it's still cooler than the 68000 which is around 60C.

Integrated USB-A works like a charm and powers the ACSI2STM while powering the ST (and a sidecartridge). Last thing to test, I guess on an original STF, is the 12V.

Adding a very crude 3D printed support makes it permanently attached to the ST while saving a lot of space inside the case compared to the original PSU.

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Just need to prepare a 1.44 floppy for this Phoenix and I will be able to close the case once and for all.
Tomorrow I will troubleshoot the other Phoenix's ACIAs issues, I hope it will be as successful as today.

[olivier.jan]

Didn’t wait until tomorrow to troubleshoot the other machine. No need for the sockets I bought this week, the problem was somewhere else.

6850CS from the GLUE was not reaching the ACIAs, but it was not at the socket level. I followed the trace backwards from the ACIA up until a via left of the MFP but after that it was going below the MFP socket, so lost track.

Bodge wire between this via and the GLUE and now everything works fine.

I just wonder how it broke in the first place. The motherboard was seating in the case, just the top cover was removed and it stopped working all of a sudden.

Linking to @exxos post on the ST536, I suspect these are very fragile PCB.

[exxos]

Linking to @exxos post on the ST536, I suspect these are very fragile PCB.

Yeah , I can't even suggest not using KB PCB (default JLC option) as their via process is even failing now. The copper doesn't look good anymore either. The solder resist comes off very easily as well now. These are the problems I used to have all the time and why I "blacklisted" like 20 PCB suppliers as had nothing but trouble. JLC, cheap yes, but I wonder how many months of my life I now wasted just because of bad PCB quality..

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I'm not sure who made the H5C1 is thats the one you have ? I changed suppliers a few times.. I've not had any issues with my C1 here and it's my daily driver.

[PhilC]

Apologies for hijacking the thread a little, just a thought @exxos there are a number of via options at JLC, one is solder filled IIRC, might be worth a try as it's not a default option.

[exxos]

Apologies for hijacking the thread a little, just a thought @exxos there are a number of via options at JLC, one is solder filled IIRC, might be worth a try as it's not a default option.

Think it was like £400 for filled.

[olivier.jan]

Yes I had a look at different types of via when ordering my small PSU PCB and prices are skyrocketing when you start changing from default options.

[frank.lukas]

I find that PCBs from PCBWAY are better quality. PCBWAY boards are also easier to solder, in my opinion.

[olivier.jan]

Maybe I will try PCBWay for my next batch of PSUs, but last time I tried, although quality was good, price was so much higher. I guess you get what you pay for…

On a different topic, pas two days were an OSSC galore…
Once the H5 was finally ready I tried with a Medusa scan converter, it works well using SCART but using ST2VGA I couldn’t get the Medusa to sync properly.

So I switched to the old OSSC and went through the tedious settings to get a nice picture on bothe LOW/MED and High resolutions, took a few hours, but I finally reached a very clean picture.
Next day, I saw a video (CTEL-ALT-REESE) explaining how to get new firmware with a simple hardware mod.
I did the mod yesterday morning, installed the new firmware and got stuck… nothing working as expected.
After reading a bit more, I discovered the mod might not be working on certain clones with a different memory chip, so basically my OSSC was bricked.

After a few hours pondering if I had to use USB Blaster to program the FPGA with a previous firmware, I discovered that the firmware upgrade had just reset the remote control connection and I had to re-pair the remote….

After pairing the remote, everything was working but… image was crap. Tried to redo the previous settings, but never managed to get the picture as good as before.

So I finally reversed the mod and went back to an old version of the firmware, just to discover the image is still crap and the OSSC is in a strange mixed mod, old firmware but some settings are now missing.

I finally managed to get a descent pictur, but it’s still far from perfect. Such a waste of time….