At the moment, you can buy the Phototransistors here: amzn.to/2xReiO6 Anything you buy after following that link to Amazon (a box of doughnuts, a speed boat) pays us a royalty for sending you there, thank you!
@@LyonsArcade Please don't call it u-H. It's like a nurse in an engine workshop. :-) The u isn't a u either. It's the greek letter mu: µ. It's just common to use u because it looks similar and µ isn't on the keyboard. The LED you mentioned, it could be a photodiode. Based on the schematic you showed, I guess it could work too. You can test the component with your multimeter accross. Measure resistance and vary the light. They are directional, so if one direction doesn't work work, try the other. If that doesn't work either, it's not a photo-diode, it's broken or perhaps reality is broken. In layman's terms an inductor is a resistor that depends on the frequency. Higher frequency = higher resistance. Capacitors are opposite. Higher frequency = lower resistances. The inductors you have are just copper wire in a coil. When you measure resistance with your multimeter you measure at DC. Ideally it should read zero ohms. This world is not ideal. Depending on type and whatsnot, values below 100 ohms can be expected. Above a kilo-ohm sounds wrong. Mega-ohms are obscene. It's probably the resistance of your fingers. I took a look at the schematic. I can't immediately see a failure mechanism for the inductor (L2). Perhaps they just live a hard life (shock, moist, etc.).
Joe's Classic Video Games Hi, i was wondering if we can turn a le 2 cab into anything better, or replace the roms for LE1. Even the LE 1 boards on ebay are over 300, seems a bit costly.
Joe's Classic Video Games top tip if your making a youtube video please mute your phone theirs nothing worse than hearing someone’s phone constantly pinging in the background either that or I hate the noise of people’s phones dinging 😂
The "LED" on that first board may still have been a photodiode. They make them in clear cases, and the internals are nearly indistinguishable from LEDs. Any PN junction is light-sensitive, and also generates some wavelength of light as current passes through it. That's why chips and diodes are fully encased with light-blocking materials. LEDs and detectors are just constructed somewhat differently to specialize to their intended use. Still, some ambient light detectors actually use LEDs for the detector. That said, the proper replacement also looks like it has a lens and side-blocking to ensure that the detected light is coming in from straight ahead and not from an incident angle.
OVAL TEEN, can you explain what the purpose that inductor is for? I don't know what they didn't use a resistor but they used an inductor any reasons why?
@@waynegram8907 The circuit may be above my pay grade :) But what it seems to be doing is the opposite of a capacitor: When the photodiode turns on the transistor, it seems to be there to cause an inverted pulse that goes to the op-amp. There's also diode CR1 that only allows current to flow back through the transistor. I think CR2 is only there to catch the flyback voltage. But you'll notice that if the gun sees too much light for too long, it basically acts as a short circuit through the transistor. That's probably what blows out the inductor. The transistor would probably also be straining under that load, unless the inductor gives out first.
What kind of digital signal is the Photodiode receiving? is it a digital encoded signal? When the transistor is turned on, the inductor is energized and stores the digital logic signal from the photodiode, and when the transistor is turned off the inductor releases the digital logic signals voltage and current which is an inverted signal to the IC op ampThe inductor is getting damaged from something since its a high stressed component that is failure rate is very high for some reason. Not sure why they used an inductor instead of just using a resistor make me wonder why?
Photodiodes and inductors are analog devices. The more light that lands on the diode, the more current it allows through it. The inductor acts as a delay device. It resists changes in current through it by inducing voltages in opposition. It's analogous to a flywheel, which wants to maintain its own RPM and resists forces that attempt to change it. The light that strikes the photodiode comes from the screen when the scan line passes in front of its field of view. If you want to see what a raster scan is like, there's a YT video by the Slow Mo Guys about CRTs and even covering LCD screens and showing why they don't work with the old light gun games. The transistor amplifies the signal, but that only acts as a trigger for the differential amp. The diff amp seems to be wired to give you a short full-amplitude pulse upon being triggered. So that's where the digital output is created. I have to amend a previous comment now that I see R8 though. Its purpose is to limit current through the inductor and transistor, which ought to prevent them from melting down. But apparently it still happens.
Very interesting. To quote my electronics teacher back in the 90's "Henrys are huge, you'll only ever see micro Henrys", inductors are always labelled L1, L2 etc.
My teacher told me the same about capacitors. "A 1 Farad capacitor would be the size of this room". Meanwhile in car audio. 1 farad is much smaller than that.
Inductors are one of those things you spend a lot more time learning about in an intro physics class than in actual electronics, because they're passive components with a physically simple theory of operation (they resist *changes* in the current flowing through them, as opposed to a resistor that resists current itself). What it's doing here, I don't know, but they show up in filter circuits a lot.
Now that you mention it Matt I believe I have seen them in filter boards and such before, they always measure almost a dead short it seems too.... thank you for the info!
@@LyonsArcade Right, they'd be close to a dead short if the current flowing through them is DC. Put AC through them and they push back, but with a delay, because they're responding to change.
One thing that I learned from the good old Duck Hunt is that when the trigger is pulled, the screen blanks white, goes black except for a white square, and blanks white again all so fast that the eyes and brain can't see/process the images fast enough, except on rare occasions. A lot of hidden psychological things went in with making these games too that people don't really notice or care to notice.
@@LyonsArcade The Henry is named after Joseph Henry, an "American scientist who discovered electromagnetic induction independently of and at about the same time as Michael Faraday (1791-1867) in England"
In case you didn't already know this, an Inductor is basically a wire wound coil surrounding a metallic core. (bust one open) It will read like a low ohm resistor. (it's basically a long length of wire)The UH in the parts list is actually microhenrys. the symbol for Micro is a Cursive like U. since there is no character like this in standard typeface, a U is used instead. UH is microhenry. mH is millihenry. Like mA is milliamps. UA is Micrco-amps, etc... I took Electronics in High School.
The three basic elements used in electronic circuits are the resistor, capacitor, and inductor. ... The main difference between a capacitor and inductor is that an inductor is used to store the energy in the form of magnetic field, whereas a capacitor stores the energy in the form of an electric field.
Hi Ron, Amazing, and informative as always... :-) Point of interest (and please correct me if I'm mistaken) - When dealing with light gun systems, there are two different types (although both are considered analog controls); 'Active' (more common) and 'Passive' (older) 'Passive' light gun systems (like the Nintendo Zapper), relied on the system replacing the target on screen with a white box for a single video frame when the trigger is pulled. The light sensor would then read the presence, or absence of the white light to register a hit, or miss. 'Active' light gun systems track the movement of the gun at all times while the system is active, and the gun is pointed at the screen.
Judging by the anvil in that led, it's at best a photo Diode. It'll give you a different signal from a photo transistor. If I'm remembering correctly, a lot less gain than a transistor
The colour chart will still work with inductors, but they are not measured in ohms, they are mesured in Henrys. You will find majority are micro-Henry's - uH. Inductance is different to resistance. Inductance is the tendency of an electrical conductor to oppose a change in the electric current flowing through it. In general they are made of a certain number of coils of wire with a ferrite core. The inductors will sometimes get open windings. You can measure the DC resistance, but it won't ever match the colour code as ohms :)
Ahhh, that makes sense. So it was correct and the chart was correct, I just didn't have a way of measuring the little Henrys :) Thanks Brendan for the Inductor explanation, I've seen them before but never had to mess with them. I ordered some to try to fix the rest of the boards!
Definitely! The original ones didn't have that little bracket, but they kept having the phototransistor legs break, so the redesigned the gun slightly and made room in the housing for that little bracket, it helps a lot.
I think I ordered those same ones, but another gentleman is telling me he thinks the part list was wrong because it's labeled differently on the part and the schematics! So we'll see in our next video fixing light guns I guess!
Hmm I am interested in this kind of stuff, I like to save old electronics and I like to repair my machines and keep them original. I guess this video is for people like me. Thx for the great content. Ohh and I see you shared a link for the phototransistors. You are just wonderful. Be safe and have a great day.
Thanks Toble I'm going to test it to see if it shoots light out, like you said though the previous person probably knew enough to put a different type of phototransistor in it....
Darn your "cha-ching" cash register sound effect. Watching your vid on my phone, and I'm thinking I'm making a killing selling stuff on Ebay. Same sound. Then I realized its your video!! Enjoyed it nonetheless.
Inductance is measured in " Henry's" Im not kidding you ! also they are read as resistor colour code ,so that reads 5.6 Micro Henrys , and that's how ya say it before anyone starts crying ! Just as a side note LEDs can be used as photodiodes, they are sensitive to light at about their emission frequency, so red LED sensitive to red light, but the chances of this working are remote at best, i did a study on this in my younger days and they behave like little solar cells, but yeah, it's still the wrong component so still a little dumb ! good point about in circuit testing of resistors, that's often forgotten, also strange about the inductors as they are not much more than a coil of wire around a ferrite core, maybe someone reading this could explain this as its not obvious to me from the circuit as to why they failed...Great vid !
Yeah I'd be interested in knowing why they failed too.... and without any physical signs, usually a resistor will burn but these look new still... Thanks for the info about Henrys AndyMouse we appreciate it :)
These inductors are made of a very thin copper wire. They can break open with shocks and being susceptible from thermal stress. They're also called RF chokes. I examined the schematic. The reason why they put a choke in there is not obvious. The entire circuit is a photodetector with an attached inverter acting as an over-supply-voltage pulse generator (the transistor, inductor and diode thing). When the phototransistor detect light it will made the transistor into conducting making its collector near GND. But when the light comes off the sensor the transistor opens making the inductor to produce an over supply voltage peak because of the inductive flyback phenomena (see SMPS boost converter). The diode limits the voltage on this phase to prevent it from developing RF noise and further wearing on the transistor junctions. That over-supply voltage pulse pass through a bypass capacitor to an analog comparator (The LM311 part) which detects it and then sends an amplified version of this pulse down to the main board through the GUN pin. I found them on ebay pretty cheap www.ebay.com/itm/RF-Choke-Drum-Core-5-6uh-5-510mA-B82141A1562K-made-Epcos-30pcs-Z1515-/253238951531?hash=item3af637be6b Also, like any other diode a LED is also a photodetector and a photovoltaic cell. If the transistor fails short between collector to emitter it also likely to burn the inductor/choke. For the LED as photodetectors: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-6WGKz2sUa0w.html The transistor can also be replaced by any small signal NPN one such as the BC548 or MPSA06 The 2N3904 is a classic, but kinda vintage one.
I've seen that a couple times but I'm going to have to go find out who this Daddy Dave guy is that's ripping my voice off! Thanks again for watching Herb!
They taught me about inductors back in the day, but off the top of my head I don't remember what was special about them. I think it's made out of a little coil of wire, and its resistance increases with the current, or something like that?
Hi Looking at the schematic. When there is light on the photo diode the 2N3904 transistor is turned on. This puts the inductor directly across the power supply rail via the 47 ohm resistor R8. The inductor would then have quite a high current flowing through it. I am wondering if the guns are left hanging looking at light when not in use. This may cause premature failure. Most inductors of this size will only have a continous current rating of a few tens of milliamps at the most,
Hi Pete; When I was looking into buying replacement inductors I noticed that like you said they're not rated very high, that very well could have been the issue and it's interesting that more light may burn them up, I never thought about that, it may literally be an issue where depending on their location they get more current through them! Thank you for the info, we appreciate it!
Joe's Classic Video Games You are welcome. I just love your videos. Keep them coming. As a test you might try increasing the value of R8. To perhaps 100 Ohms. This would reduce the current through the inductor, but of course may reduce sensitivity. Worth an experiment though are there any signs of R8 getting warm. Discolouration perhaps?
Also went on Amazon to see if they were letting toilet paper be sold on there. Talk about price gouging. 48 roll pack of toilet for over $200. Like really! Thank God for friends that own a motel supply business and a friend who has a motel. Going through friend to get case of tp.
Man it's so crazy, when I was younger we used to buy a case of like 100 rolls of toilet paper, bulk like you're talking about, from the flea market for I believe it was $20. I cannot understand where the hell all the toilet paper has gone, they still make just as much or more, nobody shut down, what are people doing with it? It's just craziness.
Another entertaining video as always! Old EE here. Your inductors are marked silver-green-blue-red-silver, which is 5,600 microhenrys (uH), or 5.6 millihenrys (mH), with a 10% tolerance. The parts list is wrong but the schematic is right, so make sure you order the correct part. See here for how to read inductor color codes: learnabout-electronics.org/ac_theory/inductors04.php.
Thanks engmcgill I ordered some more but I based it on the parts list so I probably ordered the wrong ones, lol.... if I did I'll reorder, thank you I didn't catch it!
@@waynegram8907 Good question, Wayne. I think it serves two purposes. First, since inductors resist rapid changes in current, it limits the current through the transistor when a pulse of light is seen from the CRT. Second, since the inductor smooths the fast edge of the pulse, it limits the noise coupled to the power supply line (the top side of the inductor in the schematic), and over the cable back to the console. Perhaps they were trying to meet some radiated noise spec. That's why the two ferrite beads are on the board-to filter noise to and from the board. What I don't like is that the only thing that limits the transistor's collector current when the gun is pointed at a bright, steady light, such as a sunny window, is the inductor's DC resistance. Maybe that's what's blowing the inductors, since some of those little ones are only rated to handle a few tens of milliamps. Also, that 2N3904 is only rated to 200 mA, so with the 5 V supply rail you need at least 25 ohms of resistance on the collector to keep from frying the transistor. If you replace that inductor with one that has the same inductance (5.6 mH) but a lower DC resistance, it could blow Q1. I would just replace the inductor with a 100 ohm, 1/4 watt resistor and it would probably work. EDIT: I just noticed the 47 ohm resistor on the 5 V supply rail, so I guess the transistor is safe even if the inductor's resistance is lower than the original's. However that will still provide ~100 mA through the inductor and may be what's frying them.
thanks for the help, What kind of digital logic signal is the photo transistor receiving? it is some kind of encoded signal. What Frequency is the photo transistor receiving this digital signal at? I think the Ferrite beans are there to cancel out noise to prevent false triggering the IC input pins. The BAD inductors DC resistance measured higher than 40ohms or more, but the GOOD inductors DC resistance measured 30ohms which is more mA current to damage the transistor. I find it unusual that the higher DC resistance inductors were BAD because higher inductors DC resistance is preventing the transistor 2N3904 to get damaged since it has less current going through the emitter to collector junction of the transistor. The Photo Transistor is set at a certain frequency because you can't use any Photo transistor because each part number will be set at a different frequency to be received which is overlooked by repair techs.
@@waynegram8907 There's no special encoding, other than the fact that the flash of light is generated by a CRT. One scan line is 63.5 microseconds, so the signal seen by the pen is only a couple of microseconds (probably a series of pulses for the many scan lines in the field of view of the gun's lens). See sebastianmihai.com/crt.html and www.atariarchives.org/creativeatari/Build_Your_Own_Light_Pen.php for more info on CRT scanning and light pens. The higher resistance inductors were bad because the wires in them were fried and went open circuit. An ideal inductor has zero resistance, but real ones, especially small ones with relatively high inductance like the inductors in the game guns, are made from many turns of extremely fine wire. That's why they have tens of ohms of resistance and can't handle much current. I think the gun design is flawed because a bright, steady light can cause 100 mA of current to flow through the inductor, destroying it. That's probably why Happ redesigned the board to eliminate the inductor.
I'd be interested to see if those things are usable with the cheaper (almost 1/10 the price) led-looking phototransistors. LTR-3208 looks like a decent candidate.
Nel I think they may be if they were similar for sure. I've been hoping someone would figure out a good substitute, even worse is the original light guns for Lethal Enforcers, we don't even know what part was originally on there and almost all of them have went bad over the years! I wish somebody with knowledge would figure out a good replacement for them as well.
looks like you found the the inductors at the same place I did. Still 8 bucks shipping kinda sucks unless you are going to get a bunch of other stuff there and lump it all together. The advertising thing is pretty common. I have had a few sites where I use different places that are relevant. Ebooks make more so you might try linking up some of those that are relevant to electronics repair. Personally I don't care for patreon and other stuff similar to that. I would rather kick someone a few bucks directly or help with other stuff, I went out to SV Seeker and helped do a little work. I am a computer geek though. I use a couple GPU's to heat my house during the winter. Basically I cell GPU cycles to the highest bidder and get paid in BTC. Electricity cost is about 35 per month to run it 24/7 and I get about 30 a month back but since my place is all electric I consider it a rebate, LOL. A couple years ago I was making enough that even running it during the summer I made a few bucks over the electricity costs. Was able to upgrade some of my network to 10Gb fiber optic. I would rather someone kick me a couple bucks in BTC than to use patreon or something like that and make other people wait for stuff or have exclusives.
We do a similar thing at our shop, in the back of the store it has these old flourescents that we turn on in the winter and the lights heat the building up. The games actually give off a lot of heat too, if you turn ten of them on or something which we kind of need to do for display, it causes a lot of heat in the winter. Those GPU's you've got must run hella hot!
@@LyonsArcade Uhh, I think they run around 140F (60C) each and I have 3 running at one time 2 GTX1080's and one RX480 unless I fire the one in my desktop up (another GTX 1080) as well. Add a box fan on and it stays pretty warm except on the coldest days. Then all I need to do is throw something in the oven for a little bit to drive the chill off.
I've tried replacing them in the past on some to fix them but never could get any to work with replacing them so I guess most of these are still doing their thing for now!
Hi guys. I’m working on a Taito Operation Wolf. The gun is missing the barrel on the end and the lens is missing. Have you worked on one of these before? Wondering if the type of gun in you video has the same type of lens
I believe it's different, they basically do the same thing but it's a different size. I think that end piece with the lens comes completely off on an Operation Wolf... the good news is so many of them have been parted out I think you can find parts for them on ebay. Also if you check www.TwistyWristArcade.com he reproduced the gun board awhile back too...
@@LyonsArcade thanks, I play this with Sinden light gun lol, I only have 1 gun. I chose this game because it has an internal bezel so the Sinden border will not overlap the part of the screen that is displaying the gameplay. I prefer Sharp shooter but my PC can't handle that one unfortunately.
Great video, thoroughly enjoyed the tinkering. At the 29:30 mark, when you talk about the green inductors it looks like they are the same (by the markings) but that one is reversed to the other orientation wise. Now, I'm below novice level when it comes to knowing how these parts work but I know that some stuff has like a +/- thing or something to the likes of that and I just needed to ask the question; Did it have the same value regardless of its orientation, did you test that? Just super curious :)
That's a good question, I did test it both ways and it tests the same.... you're correct though, some items need to be orientated a certain way for sure. Resistors do not though, and this Inductor I believe is just a type of resistor or at least similar in that it can go in either way. Thanks for watching Joakim, we appreciate it!
@@LyonsArcade An inductor is a conductor wrapped around a core. So no, they don't really care about polarity when measuring resistance. BTW, you've seen naked inductors. Chokes for filtering and torodial inductors(doughnuts wrapped with wire) in transformers/power supplies.
Joes classic, what is that L2 5.6uH used for in the lightgun circuit, I'm confused why the used an inductor instead of using a low value resistor. the uH or mH means milli henry or micro henrys?
I'm not completely sure myself Wayne unfortunately, someone down below explained how they feel it works though so they'd probably be better at explaining it than me.
Inductors are completely different to resistors. You wont see many as big as milliHenry's. Most will be microHenry's. The Greek letter mu ( looks a bit like a u ) is the symbol for micro. The lower case m represents milli. Calling them mu Henry's would be quite appropriate to keep the trolls silent. I haven't had a good look at the circuit, but I would guess the inductor is part of a tuned circuit with a capacitor or maybe even a small free running oscillator circuit. I would guess there would have to be some kind of timing reference on the board.
When you have time look at the schematic I don't think its a tuned circuit, their is a purpose for that inductor to do something with the encoded digital logic signal. What type of digital signal is being received by the photo transistor? is it an encoded digital signal?
For NES, it would blank the screen for one frame, then place a white square where a target is and see if the detector went off for that frame, then continue for the number of targets. So, similar. The arcade versions may have been more sophisticated though.
The NES arcade games worked pretty similar, we have a video on here of "Vs. Duck Hunt" and there was actually a setting in the manual to make it more or less accurate, which I assume was changing the size of the hit box around the targets!
I have two different ones, I have the Pocket Programmer II which mainly just does eproms and works better for me for the really old stuff like 2716's... and I have a Minipro TL866II programmer that's super cheap but works great. It would be a great entry level programmer... eventually you'll find any programmer you dont' like the way it does a certain thing, or it doesn't handle this particular chip properly, etc. so you'll probably end up with a few different models. I had a GQ-4x programmer and it broke a couple days after I bought it, the company wouldn't stand behind it and wouldn't even answer any contact, I signed up for their 'forum' to try to get technical help and they wouldn't even send me a confirmation code to get on the forum. Horrible company!
I was looking for something to add to my amazon purchase that would send a message.. but Mighty "Joe" Young and "Ron" White really doesn't interest me. ^^
I always felt, like Hoarding, was filthy or there was food and cockroaches involved. I can't be a hoarder, all my stuff, is kind of for sale :) Thanks for watching Herb!
30:20 be careful not to measure your internal resistance ;) darwinawards.com/darwin/darwin1999-50.html (those MRD300/NTE3032 parts are like $10/pcs, maybe they were trying to find a more cost-effective replacement)
I think you're right, I looked them up thinking I was going to buy a bunch but like you said they're NOT CHEAP! Thanks Samuli, see you on the next video!
