exxos's Atari, Amiga & retro forum

Okay, so I've reason to believe that my Mega STe's cartridge port is dead.

Does anyone have any good pictures of the motherboard showing the
fuse location for the cartridge port?

I've got a Robokit cartridge and I couldn't get it to work in my Mega STe
so I tried it on my STacy and it worked there.

So I'm thinking fuse? Thanks all.

Darklord wrote: 30 Sep 2025 05:22 Okay, so I've reason to believe that my Mega STe's cartridge port is dead.

Does anyone have any good pictures of the motherboard showing the
fuse location for the cartridge port?

I've got a Robokit cartridge and I couldn't get it to work in my Mega STe
so I tried it on my STacy and it worked there.

So I'm thinking fuse? Thanks all.

Looking at the pictures over the motherboard forum the fuse looks to be promient right next to the port (near the middle electrolytic cap on this one, for example):





At least that *looks* very much like a fuse to me!

BW

Thanks. Lp gave me the relevant portion from the Mega STe schematics
on his site - so that should help immensely.

The component that Badwolf identified in the photograph IS the one ringed in the schematics, F21 (presumably Fuse 21?)

Just behind (to the right in the photo) the cartridge port connector.

@Badwolf

@alexh

(and lp of course)

Thanks guys - the fact that it appears to be an actual fuse
helps. Even I should be able to find it and replace it, if it's
actually bad. :lol:

Well, just to rule things out, and because it was the last thing I've added to my
Mega STe since I used a cartridge in it, I removed the ATW800/2 card, just in
case it might have been a conflict.

And...it wasn't. The Robokit cartridge doesn't work with it removed either.

I really didn't think it would be, but it's better to be safe than sorry, right? :)

So I finally got around to taking my Mega STe apart and looking at the cartridge port fuse.

It's easy to get to - you literally just have to remove the top cover and it's accessible.


I zoomed in on it - can you tell from a picture if it's blown or not?


Would this be a suitable replacement? Thanks all.


[EDIT] I posted the wrong picture above - it's the 0.5a ones that
I'm asking about...

You would have to check the fuse of the multi-metre on something like low resistance test..

The cartridge port fuse I believe is 0.5 Amp and the one you list is 10 amps which would be very bad..

Looks blown to me but check it with a multimeter in continuity mode, you shouldn't get a beep, just open circuit.

Also, there is a ferrite core next to it, L204 it looks like, and it looks like the right hand end (In the photo) has a dry joint.

exxos wrote: 04 Nov 2025 21:12 You would have to check the fuse of the multi-metre on something like low resistance test..

The cartridge port fuse I believe is 0.5 Amp and the one you list is 10 amps which would be very bad..

Right, it's another one of those you can't tell just by looking situations. Gotcha.

Er, yeah sorry about that - I posted the wrong picture and mentioned it at the bottom.

Thanks.