Indeed, well spotted. I was born in 1978 and I was *obsessed* with LEGO, in particular space LEGO, throughout my childhood. Glad that you enjoyed the video. Be sure to check out my other, more comprehensive, QM videos. (Also, stay tuned, though my pace is glacially slow.)

@@Vanya_Avan Hello! Sorry to hear about your troubles. I will be traveling the next days, so I cannot look into it immediately. Maybe you can send more details about the behavior of your camera to my email: edwin dot steiner at gmx dot net. In particular, what do you mean by "measurement off"? Do you mean the open aperture metering mode?

@@EdwinSteiner Thank you! That's right, when the exposure metering mode is turned off, the arrow reacts to switching other parameters. I will email you a more detailed description of the problem and a link to a video of the problem.

yes, lye will probably work well. just give it enough time to dissolve the glue. some keys not working is likely due to oxidation or dirt in the switches, not the glue. i had some dead keys before and i could fix them by disassembling and cleaning the contacts *very carefully* with isopropyl alcohol and lightly rotating an eraser head of a pencil on the contacts and then dusting off.

@@EdwinSteiner Thank you very much Edwin. I'll pull the circuit board and do the cleaning as you described. I really appreciate your work here. Cheers.

@@EdwinSteiner LYE UPDATE: I highly recommend Lye, I had read that it can have a pH of 12-14 in high concentrations, so I bought 100% lye crystals, mixed a strong concentration: about 1/3 cup (80mL) of crystals in about 1/2 gallon (1900 mL) water and let it sit for about 18 hours, the weights either had fallen out or fell out of 20 of the white keys and 3 of the black keys with no prying, and no visible red glue on them. 2 more white key weights pried out easily. I'm letting the rest sit in a new equally strong solution for another 24 hours or so.

@@EdwinSteiner Lye Update 2 : After a 2nd soak of 12 hours all of the weights either fell out on their own or came out very easily with light prying using a dental pick. So for anyone whe can't find the drain cleaner he used or can't find the pH of common drain cleaners (I couldn't) I recommend lye. Of course you'll want gloves and eye protection.

Amazing! Congratulations on your purchase! They are very special cameras, marking both the end of the era of fully analog, discrete electronics and the beginning of the era of automatic electronic SLRs.

What drain cleaner did you use? Did you try Lye?

I'm glad that you liked it! The quantum mechanics videos are the reason I created the channel. The Pentax project was more of an accidental excursion. There will be more QM videos but they take a long time to write and produce. Due to the low number of videos I did not want to split into multiple channels. Now I know that at least one person cross-discovered the other topic.

Thanks! I made this slotted screwdriver myself using a Dremel to grind the slot into a regular old slotted screw driver we had lying around. I also had to grind it a bit flatter to make it fit. So, unfortunately, I cannot give you a link. If you don't want to make it yourself, you could try searching for "face spanner", which I think is the name for a tool with two frontal prongs for turning fasteners.

Hello Mike! Congratulations for getting a working one! Interesting that a camera with the lower serial number has the spring in the removable screw, which is the better design for this polarity, in my opinion (no risk of shorting anything out with the spring and easier maintenance of the spring).

Hello Edwin. Yes. I can send photos if you want them. I cant find your email here. I have a realy big spotmatic collection and lenses by the way. Mike @@EdwinSteiner

Quite the claims. Re: "probability is not a property of "nature"" -- How do you know that? -- Re: "but merely a measure of uncertainty in the observer" -- Why "merely"? What tells you that what you find in the observer is not a property of nature? Where is the boundary between the observer and "nature"? It's not clear to me what you try to say with the following points, but don't overlook that probabilities may be 0 or 1 in some cases. Probability does not exclude certainty.

@@EdwinSteiner Why "merely"? Because probabilities change dependent on the amount of information afforded the observer. You showed this yourself when you demonstrated that the "Heisenberg cut" can be arbitratrily placed. At least I think this is what you meant to show. If not, then the inconsistency that you claimed to refute is indeed present: for e.g. a scientist who is observing another scientist who is observing an experiment whose result is unknown to the first scientist. I agree with your last sentence. But you assumed, rather than argued for, nature having "no true statement beyond probability". If the formula "no true statements beyond probability" is meant to be univocal with "the only true statements have probability 1" then your problem is the principle of contradiction and its equivalent (or derivative if you prefer) the law of the excluded middle: the claim they affirm of reality that what is real either is, or isn't, with no 'in-between' status is more certain than any argument you can make to the contrary - indeed you have to affirm them in order for there to be such a thing as contrary! I appreciated your clear rhetorical manner and the time you put into the video - you are some teacher! But mistaken here I think.

Thanks! The 2nd part is planned but it will take a while. Some other QM videos will be published before that. I'm not sure what you are asking about the Bloch sphere. Maybe you can give some more context or a pointer to the mathematical expression you are confused by.

I can't find his drain cleaner where I live in California, I read that high concentrations of lye an have even a higher pH than he used so I'm going to try lye. I'll look for the Biscon glue, thanks.

Good luck! Consider checking the comments for tips and experiences from multiple people.

@@EdwinSteiner I certainly did!

Hello and thanks! No, other camera repairs are not planned at the moment. This was a quite unique project for me. Future planned videos are mostly about physics plus maybe some programming and electronics.