OSSC v1.8 freezing and behaving strangely

[rt]

I’ve bought an OSSC v1.8 from VGP about two years ago. I think it had firmware v1.07 or v1.08 installed before I’ve upgraded to v1.20 a few days ago. The update succeeded and then I have used the device for that evening.

On the next day, the OSSC failed to start up properly. The OSSC showed its startup message displaying the firmware version (1.20), but didn’t react to any input. HDMI output was generated, showing the test image, but otherwise the device seemed dead. I tried various things, power cycled a few times, then suddenly I was able to change inputs using button 0, only the input names were messed up (garbled strings). The same garbled strings were visible on the TV. Opening the menu didn’t work because the OSSC still didn’t react to the remote control.

Unable to change the firmware from the menu, I grabbed my USB Blaster, installed Quartus Prime Lite, and followed the instructions for installing firmware via JTAG. Since there is no .jic file for v1.20 on the GitHub release page, I’ve used the ossc_1.01-aud.jic file as found at http://www.infocult.com/m/ossc/fw/v1-series/ (linked from https://junkerhq.net/xrgb/index.php) for the purpose of upgrading to 1.20 again.

Quartus detected the device, flashed the firmware, but the CRC verification step failed. Anyway, the OSSC display showed 1.01a, the remote control worked again, and I was able to open the menu, so I played around a bit. Then, the OSSC started freezing and behaved similar to before with firmware 1.20. JTAG revived the device again, again with CRC error, and it stopped working again after a few minutes of use. I’ve flashed several times, tried other .jic files, but the CRC verification step failed each time.

Given that I see these CRC errors, I guess that the SPI flash memory chip (U10, labeled IS25LP016 DNLE) might be broken. Is there a way to confirm this? Or could there be something else which may cause the problems I have? I want to be reasonably sure about this, as the IC is rather difficult to find and also quite expensive.

Thank you!

[rt]

So, I started measuring a bit. Voltages on the regulators were off, first just a little bit, then it got worse and suddenly the display light went out. Fuse F1 got very hot and had a resistance of around 24 ohms (measured after having removed it).

I’ve bridged the fuse with an ammeter, and according to that, the whole device draws around 229 mA. Does this sound about right or is this too much already? Maybe it was just a bad fuse after all…

• This reply was modified 5 days, 16 hours ago by rt.

[marqs]

229mA sounds a bit low if there is an analog input active, but possibly normal if it’s idle / outputting just test pattern.

[rt]

Yes, it was just the PCB without any cables other than the PSU connected, as idle as can be. Good to hear that this might be normal.

I’ve ordered some new fuses and will check again after having replaced it. I don’t want to risk frying anything by bypassing the fuse for longer than necessary.

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