this post was submitted on 10 Mar 2026
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A bug in the system. (aussie.zone)
submitted 16 hours ago* (last edited 10 hours ago) by tuff_wizard@aussie.zone to c/askelectronics@discuss.tchncs.de
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Merlin rollerdoor (Australian garage door brand) stopped working, when investigating I found a bug had shorted itself across an IC (labeled HVS004).

Luckily Merlin sells the whole replacement unit for only $449AUD. Before I pull the trigger on that I was wondering if anyone here could advise me on my chances of success if I just replaced the burnt bit.

I’m happy with larger electronics but I’m struggling to even identify any fuses on the board to check.

I’m also unable to find a replacement IC online as the code on it seems to be associated with some kind of blue LED. (I also don’t know for sure if the IC needs to be programmed or if it is just standard)

The back of the board is fine, just thru-hole solder connections.

here are some more photos(new link, should work now), hopefully in good quality.

Thanks in advance

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[–] tofubl@discuss.tchncs.de 2 points 6 hours ago

Looks like a switching regulator. Why there are two of them I don't know, but all those electrolytic caps, inductors, and beefy diodes around there are very telling.

The fuse is labeled as PTC so should be a resetting type that does not destroy itself on overload.

If the problem was indeed a bug shorting out the IC itself you probably have a good chance of getting it back by just replacing the IC, if you can identify it.

[–] pcgaldo@lemmy.ml 1 points 6 hours ago* (last edited 5 hours ago)

When you identify the component and find replacement, before welding and testing, check that there are no short circuits on the tracks. Pay particular attention to those surrounding SMD capacitors and diodes.

If you have a lab power supply, you can try to see if they heat up by injecting 1 volt and limiting the current to 1.5 ampers. If you don't know how to proceed, there are videos out there that explain it.

[–] partial_accumen@lemmy.world 19 points 15 hours ago (1 children)

For others looking at this, the damaged IC is silkscreened as IC7 (red square in my edit of OPs pic). OP, the fuse on this board is the green SMT device (that I put a green square around). Here's the sales sheet for that fuse.

OP you gave a part number for the blown IC as HVS004, but from what little I can see in the picture I'm wondering if its something else. I've put a BLUE square around another IC8. I'm guessing thats in the same family, from where it is in the board. However, I can't see what the part number is on that one. Can you share that one?

[–] tuff_wizard@aussie.zone 3 points 10 hours ago (1 children)

hey mate, I've added changed the link to the album. those two both have the HVS004 code on them which you can see in one of the new images

[–] partial_accumen@lemmy.world 1 points 49 minutes ago

Much better pictures, thanks! I had suspected that both those ICs work together (and it looks like they do), but I couldn't find any part that matches it in any searches. It could be a specialized ASIC they made, or they could have bought proprietary marked ICs specifically to prevent the kind of repairs you're wanting to do.

Apologies I can't help further, you may be stuck buying a new board. Maybe keep the dead one around in case you need a replacement part in the future.

[–] Nawor3565@lemmy.blahaj.zone 4 points 14 hours ago (1 children)

It seems like the Imgur album only has a photo of the back of the board. I think HVS004 might be the wrong number, can you take a close up photo of the chip (and surrounding circuitry) with a flash for a clearer view?

It's also weird that a bug could have fried itself across a chip that only runs off a few volts. "Bug zappers" usually use at least a few kV. Maybe that IC runs off the 33v line or it was a particularly wet bug, but I suspect that might not be your issue.

[–] tuff_wizard@aussie.zone 1 points 10 hours ago

hey mate, I've updated the imgur link with more, better quality photos. it might not have been the bug but it sure did short as you can see from the images

[–] mvilain@fedia.io 2 points 13 hours ago

Had a slug short out the power supply on an ancient Doorking security door. They don't make that version any more so we upgraded both systems. Now AT&T is charging $350/mo just for the phone line, so these systems have to go. Don't know what the HOA decided, but at least it won't cost a monthly fee. Let's just hope the HOA President stays in office as we use her Internet connection to run the entire complex's network.

[–] BakedCatboy@lemmy.ml 2 points 15 hours ago* (last edited 15 hours ago)

Is it that 8 pin ic above the start label in the bottom? Finding a compatible replacement would be made easier by figuring out what it's inputs / outputs are. Someone who's familiar with common ICs could probably deduce it by looking at what it's connected to - a good start might be to figure out which pin gets power at what voltage when it's plugged in, and which pin is connected to ground. I guess it could be a programmable microcontroller but I think it could be a number of other simple things too. Sorry I don't have any guesses