OSSC 1.6 Not Turning on?

[YuuLeee]

Hi!

So I used the OSSC about 2 weeks ago and it worked perfectly with my arcade board but I tried to turn it on today and the screen on the front of the OSSC turned on for a second and then it just shut off. When I tried to turn it on again the little LED marked D1 next to the screen would flash red but the light wasn’t to bright but now its not doing anything when I try to turn it on. I’m not sure if this is something I can fix myself since I have zero experience with trying to fix electronics but i’m definitely willing to try. I’m assuming a fuse blew out but I have no idea.

Thank you!!

[BuckoA51]

Sounds like you connected the wrong PSU to the unit?

[YuuLeee]

Id have to double check since the gscarts PSU looks the same but I thought I put a sticker on them to separate them unless I just totally suck. I guess either way what can I do to fix this if possible?!

[BuckoA51]

If you connected the wrong power supply you will need to return the unit for repairs/servicing I’m afraid.

[YuuLeee]

Thank you for the reply!

[Kev79]

The same thing happened to me.
The GScartSW Lite PSU looks almost identical to the one shipped with the OSSC, but is using 9V instead of 5V.
Of course I am a moron and grabbed the wrong PSU from the drawer :-(.

From now on I will label all my PSUs and cables…

[nmalinoski]

Perhaps it would be prudent to encourage users to label their cables? (Points for alliteration?)

A while back, I bought a pack of zip-tie cable labels like these to label the power cables of my consoles and analogue video equipment, specifically where I connected them to a rackmount surge protector, in case I needed to unplug anything; but these would work equally as well where they plug into the consoles/devices themselves.

I know the power supply VGP sells for the OSSC is an off-the-shelf component, but I’d like to see labels added to both ends of the cable, and then point out to people that it’s labeled on the relevant product pages.

Labeling power cables is equally valid for any other device, including superg’s switches, though the next revision of the gscart is expected to use MicroUSB for power.

[ThePorkchopExpress85]

I just did the same thing. It began smoking immediately for a couple of seconds before I unplugged it. I never even had it turned of. So angry. Is there really no way to fix this myself? I have very good soldering skills.

[BuckoA51]

Absolutely it’s just a matter of identifying the diode or blown component and replacing it.

[ThePorkchopExpress85]

I’m going to guess F1 and D5. There’s continuity between them. I believe I read that that is not how it should be.

[Morpheus_79]

Continuity on F1 is a good thing, cause F1 is a fuse… and continuity shows: it’s not blown.

D5 is a diode. So continuity on D5 is a good thing too – but only in one(!) direction. There should be no continuity if you switch the probes on D5 (to test continuity in the other direction).

As far as i remember (someone correct me if i’m worng), the voltage regulators U5 and U6 are directly connected to the 5V input. So it’s very likely you’ve fried one of those two by connecting the wrong power supply.

[marqs]

As far as i remember (someone correct me if i’m worng), the voltage regulators U5 and U6 are directly connected to the 5V input. So it’s very likely you’ve fried one of those two by connecting the wrong power supply.

D5 is TVS diode that clamps voltage to 5V (in reality effective clamping voltage is a bit higher and depends on current), protecting from surges and overvoltage. When continuous overvoltage (or negative voltage with more than ~0.6V amplitude) is applied, it burns into a short circuit so that downstream devices are still protected. That eventually triggers overcurrent protection (e.g. fuse) if such is present. The diode and fuse are placed before power switch, so if you hadn’t power turned on yet, then you almost certainly did not damage anything but the diode.

[ThePorkchopExpress85]

I’m just going to order F1, D5, U5, and U6 to be on the safe side, but I’ll certainly start with replacing D5 first. Not sure why this particular diode is so hard to find in stock anywhere. Anyone know a secret about finding them somewhere that won’t take months? Is an SD05TCT from mouser okay as a substitute? The specs look the same except for the voltage breakdown, 6V instead of 6.2V

[Morpheus_79]

D5 is TVS diode that clamps voltage to 5V (in reality effective clamping voltage is a bit higher and depends on current), protecting from surges and overvoltage. When continuous overvoltage (or negative voltage with more than ~0.6V amplitude) is applied, it burns into a short circuit so that downstream devices are still protected. That eventually triggers overcurrent protection (e.g. fuse) if such is present. The diode and fuse are placed before power switch, so if you hadn’t power turned on yet, then you almost certainly did not damage anything but the diode.

Thanks for clarifying it marqs. I was looking for the OSSC 1.6 schematics but couldn’t find them. So i took an assumption from the back of my (bad) memory.

I only just remembered, that there were OSSC 1.5 schematics available and i saw, that F1 and D5 were indeed placed before the power switch:

I’m just going to order F1, D5, U5, and U6 to be on the safe side, but I’ll certainly start with replacing D5 first. Not sure why this particular diode is so hard to find in stock anywhere. Anyone know a secret about finding them somewhere that won’t take months? Is an SD05TCT from mouser okay as a substitute? The specs look the same except for the voltage breakdown, 6V instead of 6.2V

I’ve used a SD05T1G for D3, D4 and D5 in the past. But at first glance an SD05TCT seems to be suitable too…

[ThePorkchopExpress85]

Thanks to everyone who replied to my problem. I now feel very confident about the components I ordered and fixing my OSSC.

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