The Set of Haunted Electronic Horrors

Cyberdragon

LEGO makes mistakes sometimes, we all know that. But some mistakes are down right sneaky and dastardly! As a child, I would occationally be haunted by a mysterious and disturbingly creepy noise in my room at night. It was sparatic, coming and going and pulsating in volume. It sounded like a cross between an old dial-up modem and the alien sounds from "Signs". One night, I got the courage to find the source of the noise. It was none other than #4095, which was switched off! I tried pressing the reset, turning it on and off, but I ended up just having to remove the batteries, thus losing my data! (It's all RAM based, which is why it's still powered when off, the noise faded out eerily from the capacitors when I removed the batteries too) I don't know if LEGO knew about this, or whether this was even common or my set is just faulty, but either way, I'm pretty sure creepy and annoying noises coming from LEGO sets is going to scare kids. When I get the time, I'll do a teardown. I'll post a basic overview here, but I'll be doing a detailed circuit analysis and diagnostic with an atempt at a mod or repair over on an electronics forum. (I'll post a link here if anyone is interested) Other than this fault though, the set is pretty good...except for the derpy robot on the front of the box with it's head connected directly to the reset switch so every time it tries to move it just spasms until the head falls off and it tries to run over it. (again, disturbing to kids, and also just a plain failure of design)

Jackad7

I highly doubt it was just a ram related issue. If I remember correctly skynet passed off early warning signs to Some thing similar...

Cyberdragon

I have two theories as to what's causing the noise, either there is a missing decoupling capacitor on the CPU or RAM chip, causing noise in the audio synth chip during RAM updates (which shouldn't be powered when off though), or the speaker/piezo is connected directly to the CPU and it's a software bug. Either way, shame on LEGO, at least they don't do that crap anymore...unless we start getting reports of Mindstorms sets making funny noises. It would be a hilarious prank to hide one of the 4095 control bricks somewhere as an annoying noise machine.

catwrangler

I laughed so hard; I never knew that set existed! When I was a kid I was given one of those little Tomy Palm Pets - they had connectors on their underside as shown here, so that when the toy was held in your palm, your skin completed the circuit and the toy would chirp/meow/whatever. Well. It turns out that it's REALLY not a good thing to have the one buried in a drawer in your spare room start meowing loudly in the middle of the night a decade later, soon after your real cat's death...

MaffyD

@catwrangler - in our house it's the lil live pets that are buried and have their buttons squashed up against another toy or whatever - that's when your youngest wakes up in the middle of the night and comes into your bedroom upset about the weird noises going on. Cue thirty minutes of searching for the darn thing before he can go back to sleep...

It's not even his toy!

CaptainLego

Maybe there was a ghost or something spooky but they got spooked by the robot as well. 

Cyberdragon

I've done a partial teardown of the set, and I think I found and fixed the problem, which was indeed a fault unique to my set. The piezo element wires are soldered right in front of the terminal where part of the mechanical reset switch is mounted and electrically connected. The bare part of the red wire from the piezo element was extremely close to this terminal, which apparently is live when the unit is off because when I touched the wire with my oscilloscope probe it started crackling. The wire was probably expanding due to heat on hot days and touching the metal contact causing static. This is still a bad design, but then again alot of this set is bad design. I might post photos of some of the guts if anyone is interested. 

catwrangler

I wouldn't mind seeing that!

Cyberdragon

Unfortunately I haven't figured out how to remove the PCB due to some nasty glue holding the wires down, but here's what I could photograph so far.

catwrangler

This must be pretty fiddly work, even by AFOL standards - best of luck with the rest!

Cyberdragon

I'm going to have to replace the negative battery wire too, since I did what all kids do and left dead batteries in it, and of course they leaked and made everything all rusty.

catwrangler

I feel your pain - I destroyed a couple of light and sound modules from my Space Port sets in the same way and had to buy new ones on Ebay last year when I found out. Which reminds me that I must go to my attic Lego lair and check all the things with batteries in, so thanks for bringing this up again!

catwrangler

I feel your pain - I destroyed a couple of light and sound modules from my Space Port sets in the same way and had to buy new ones on Ebay last year when I found out. Which reminds me that I must go to my attic Lego lair and check all the things with batteries in, so thanks for bringing this up again!