 Previously I have a new project, or you will be hit. I guess this is the coin holder Don't know what this even is for it. It does look like there is a fuse missing. Oh That's not good. All right, that's definitely not good Well, it's unfortunate, but I think this entire wiring loom has to be removed because they're all sort of interconnected So I'm going to label all of these plugs and jacks and make sure that I can put them back in the right place And then I will just plug in the things that I need to The wires just go all over the place Okay, now that I've removed all the plugs from the main transformer and power supply I can just unscrew this from the base and Remove it and examine it and test it and make sure everything is working. Okay, there's not a whole lot that can go wrong with this thing Considering that Provided there's nothing underneath. This is just a transformer with a big capacitor and a bunch of fuses But let's take it out and see Okay, well looking underneath the device we can see that there is a bridge rectifier here These are where the fuses are that's the capacitor of the transformer. There's an EMI filter over there and What appears to be just a bunch of connectors over here? So Again, not a whole lot that would be a DC power supply With a huge filter capacitor on the end. So let's just You know hook it up and carefully without touching any of the metal bits See if this is actually outputting what it should be and so here's the schematic for the power supply We can see that AC comes in here and goes through a Filter here and then it goes through a jack which is connected to the interlock switches Which are the buttons that go to the front and back door? To make sure that the power turns off when you open up the cabinet And then the power goes up to this voltage selector and you can see that there are a bunch of different voltages that you can Apply to this power supply but it all comes out as 120 volts over here and in fact there's a little tap over here that you can tap off and Get a hundred and twenty volts AC regardless of what you're inputting So there you've got the transformer. There's interestingly there's a little thermocouple here Which is interesting? So I guess if the thermocouple goes off and this has a hundred and ten plus or minus five degrees C Then the thing turns itself off So here we have the outputs Starting at the bottom. It looks like we've got 60 volts AC and another 60 volts AC circuit we have Here a fused circuit which gives six point one volts AC We have another fused circuit here, which gives thirty six volts AC and Then finally we have a fused circuit here, which goes through a diode bridge and a filter capacitor Which is going to supply ten point six volts DC And of course, that's probably going to have a lot of ripple because it's just a single capacitor on the outside so what we should do is hook up the interlock switches and then turn the switches on so that we can power the power supply up and Basically just measure these voltages and I don't really expect anything to go wrong with this So let's see what happens So I've hooked up the multimeter to the auxiliary AC out That doesn't output power until all the safety interlocks and the main power switch has been Closed so I can see that I am getting power So that's pretty good so now all I have to do is check all of the outputs here Okay, so here we have our 60 volts center tapped and it is indeed center tapped So from both ends we get 60 volts and from the middle to any end we get 30 volts So let's check the next circuit Again as expected we get 60 volts AC and now if we go to the center tap We see that we have 30 volts. So that's working Now on this circuit, we're supposed to be getting 6.1 volts 6.4 is probably just fine And here we're getting the 36 volts AC and it is indeed center tapped If I move one of the probes to the center, we do indeed get 18 volts So the final thing to check is the DC voltage Okay, and here we see a DC voltage of 13.8 as opposed to the 10.6 specified over there This has a number of reasons The main thing is that there is no load on the system And the other thing is that this is probably not a very clean wave. In fact, let's see how much ripple there is Not really a whole lot. So, you know, there's basically no load being drawn from the capacitor. So there's very little Ripple happening Which means that we are at 13.9. Now, of course as you add more load that would go down And presumably with the machine fully on and everything connected that would be 10.6 So I think that we can say that This power supply is working perfectly fine. I don't see any problems with the capacitor So we will just leave it in place and not replace it And of course because it's just a capacitor with no load connected to it when I do turn off the power supply The capacitor very slowly discharges basically through this multimeter So I could just leave it 13 volts is not lethal. It's only when you get to about 48 volts or so that things get lethal So there really is no danger here Except maybe a fright if I happen to short the capacitor terminals Now while I've got that capacitor discharging the next circuit that I'd like to go into is this Regulator slash audio board and we can see that we have the 10.6 volts going into the system along with 36 volts AC and Output we have a whole bunch of regulated voltages. So we've got for example a plus-five return Plus five return we've got plus five Regulated and we've got plus and minus sense So that will tap off of some system to make sure that we are actually outputting five volts and The regulator gets adjusted according to that We have two audio inputs And then it looks like we've got I think this is probably a bunch of outputs we've got negative five volts DC negative 22 volts DC and plus 12 volts DC and plus 22 volts DC and Then down here. It looks like we have speaker one speaker two and speaker one return I'm not entirely certain why there isn't a speaker to return but presumably Audio one and audio two get amplified to the speaker So this is sort of a combination thing what I'm going to be testing is the regulator portion of The board to make sure that that is working and I'm also going to look for that resistor that burned out right over there In order to see what function it has and I presume that it's not going to be part of the audio circuit I don't know why an audio circuit would burn out like that. It's probably more like the regulator So let's take this board out now and just poke around and see if all the capacitors are okay And all the semiconductors are Functioning properly and then we can try plugging it in and seeing if the magic smoke Goes out of that resistor and if it doesn't well, maybe I have to replace the resistor and Smoke it again. So let's see So I'm just visually inspecting the back of the board and I don't actually see anything bad in particular With one exception and that is Over here. It looks like there's some flux which usually means that this component has been Possibly replaced at some time because otherwise, you know, it would have come out of a factory clean I believe And if we turn the board over we can see that that is a heat-synced 2n 30 55 which is just a standard power transistor And I don't really see anything else bad on this board with the exception of that resistor which burned out when I plugged in the machine So We can test a few things for example, there's a diode right over there There is Transistor here's another transistor. So we might be able to test all those and see what happens In addition, I kind of look at some of these capacitors a little more closely to see if They're leaking just that for a glance. They don't appear to be leaking But But what what does worry me? Are the semiconductors mainly on this on this board and why did r29 Get so much current through it that it blew out I can take a look at the schematic and see what might cause r29 to blow Here we see the schematic for the regulator and audio board At the bottom of the schematic we can see the two audio inputs going through pretty much identical circuits to the two speaker outputs And we can also see that There is actually both a speaker one and speaker two return And those are actually connected. So that's not interesting at this point What is more interesting is the top of the schematic which shows Two separate power supply circuits. Let's take a closer look Here is the first power supply circuit. It's taking 36 volts ac Referenced to the center tap and it's putting it through a few Uh input filter capacitors A diode bridge to convert that to dc And then a few output capacitor Filters along with bleeder resistors so that when the power is turned off that bleeds off the Voltage here And it looks like these are specced to be 35 volts. So of course 36 volts ac is going to end up being a certain amount of voltage And if we take a look at where that goes well the positive side Goes through a small resistor and then to a 78 12 volt regulator, which is a positive 12 volt regulator We've got another filter input filter and output filter capacitor and that goes out to plus 12 volt dc Uh, and we see that we're actually tapping off this Which says it's going to be 22 volts dc. And of course that's going to be unregulated while this is regulated Same thing with negative 22 volts dc. That's the raw output from the bridge And that goes through a small resistor Through an input filter capacitor a 7905, which is a negative 5 volt regulator An output filter capacitor and out to minus 5 volts dc regulated So the resistor that burned out was r29, which is not in this section So we can go to this next section over here Where we see the 10.3 volts unregulated dc coming out here Uh along with the signal ground. So that would be the negative That would be the ground with respect to 5 volts Which is separate from I guess The rest of the noisy circuit ground, which I suppose is a good thing This right here is an LM 305. That is a general voltage regulator And uh without going through all of this stuff, you can see the datasheet online Basically these transistors are driven by q1 The voltage regulator to regulate the amount of current that's allowed to go through These transistors. So this is a small transistor. This is a power transistor This diet over here is to prevent Well, I'm not sure what it's there to prevent, but it's there to prevent something and This diode over here is also to prevent any positive voltage from being passed from the Essentially the ground to the plus 5 volts rail. In other words, it's to prevent the voltage from being reversed somehow Um, and these are the outputs. So we've got plus 5 volt regulated and the plus 5 volt return Which is the equivalent of ground. So that's the signal ground and we've got plus and minus sense Which basically, uh, you run the line from the output of your power supply All the way to where you're actually Feeding 5 volts and then you sense that voltage over here And this should be actually very low current so that there's not a lot of omic loss in the line That you're tapping off of Same thing with the negative sense. So we can see that there is our 29 right over there It's a 10 ohm resistor And it appears to be connected through a voltage divider over here The voltage divider is tapped off of Which provides feedback to the lm 305 voltage regulator to regulate its voltage So of course you would set that until you got 5 volts on the output So the problem appears to be that this 10 ohm resistor burned out The only way that I can figure that that resistor can burn out Is if the positive sense Were actually grounded If it were grounded then you would get 5 volts here and 0 volts here So you would get 5 volts across a 10 ohm resistor, which gives you half an amp And that resistor was in no way Capable of half an amp. So basically, uh, it would be Um, the voltage times current so The voltage here is 5 volts the current would be half an amp Uh, so that would be 2 and a half watts of power going through that resistor This resistor was definitely a quarter watt resistor. So yeah, it could not take 2.5 watts So my suspicion is that the positive sense terminal was grounded somewhere Now If it isn't grounded on this board, then I can simply replace that 10 ohm resistor with a new one Test all the semiconductor is basically just check their junctions for, you know, correct diode operation And that's a really simple way of just, you know, making sure that they sort of kind of work And then just test the board in isolation Uh, connecting basically the plus sense to the plus 5 volts and the minus sense to the 5 volt return line and make sure that we get 5 volts out If we do get 5 volts out, then that means that the problem is somewhere further down the line Otherwise we've got additional problems somewhere in here. So let's go ahead and do that So with the resistor replaced right over here What I've done is I've connected the negative sense to the minus terminal positive sense to the plus terminal And I've plugged in the 10.6 volts input And that should be enough to get the 5 volt regulator running. So We'll see what happens Okay, I will turn the machine on and so far I don't see any magic smoke So let's go ahead and measure the output Okay, so I'm just going to turn it on again because I forgot to Plug in the power that actually goes to the board. So Turning it on Okay, and I'm not seeing any problems yet I'm also not seeing any output now. That just may be because I'm on the wrong pins So what I'm going to do is hook into This ground test point here And this is supposed to be plus five here And we are indeed getting plus five volts. So I was just probably Proving on the wrong pins on the jack But in any case we are getting five volts Um And I don't see any signs of Uh any Anything getting hot Here's the circuitry on the vector generator board showing that definitely Minus sense is supposed to be connected to the plus five return And of course positive sense is supposed to be connected to plus five so let's uh Take the cable harness off and maybe check the printed circuit boards And here we have the boards are out along with the schematics So this is the vector generator printed circuit board and this is what they call the auxiliary printed circuit board And there is our lovely 6502 And this is a power LED. That's supposed to light up and another one over there So, uh, let's take a look at this Here are also the connectors They felt a bit loose and I think maybe they're just like really old But I'll take a look at the printed circuit board itself to make sure that at least these signals are connected to They should be And just checking the connections over here. They all seem fine. So I'm beginning to suspect that the conductivity of this harness or at least this Slot is not that great Yeah, so I really don't like how loose this is But I think even cleaning it is not going to be so so great Uh, luckily from some other ridiculous project, um, I have these replacements And they do fit very nicely Just like that. So I think what I'm going to do I think what I'm going to do Is maybe take this wiring harness out And just solder the, uh The wires on So here we are. I have replaced all of the connections and these two connectors with nice new ish card edge connectors and, uh I went ahead and looked at these wipers in here under the microscope And take a look at what I found so These don't look so good especially like, uh on this one You can see that they're cracked starting. Look at how loose that is. I mean This is practically breaking Uh, let's see They're pretty rusty. There is some other like broken ones cracking ones Here's a bunch of pitting and tarnishing rusting So This really was not in very good shape at all So I'm pretty glad that I replaced this whole thing Not good So I've hooked everything back up. So down here We've got the power supply going to the wall And then we've got the regulator With the audio amplifier We've got the two printed circuit boards on the side And all the way in back we see that there's a speaker over here Uh, this wire over here I think goes to two speakers up at the top of the cabinet I think Um, and this wire right over here is the one that goes to the screen. So that's the vector display So, uh, what I'm going to do is I think I'm going to Uh, watch the regulated voltage supply And let's make sure That it doesn't explode When I turn this on Here we go We don't have any burning We also have The leds on the PCB is lit So that's good And I guess the next thing to see is, uh, the front Okay, well we have lights over there And we have lights up there But as for the screen There is nothing All right, so the next thing I guess to check is to make sure that the screen is getting voltage For all I know the screen is dead Um The filament could be toast the screen itself could be toast but I guess, uh We'll take a look at what to see next So we're at the point where we got the leds on These printed circuit boards here to light up, which means that the power supply is probably good So that's great. Uh, we replaced all of these connectors. That's great But when I turned it on the only thing that happened was that the relays, uh, over by the coin slots Went off, which is I guess good the lights in the front went on which is good However, uh, I didn't hear any sound Uh, I should probably see if there's a video online of a battle zone machine Uh, maybe it doesn't make any sound when when you just power it on Uh, and there wasn't anything coming out of the monitor So let's look at the underneath Of the monitor section So this is a driver board which takes the vector inputs And uh converts them into signals for the crt, which is up there Uh, it also takes 60 volts ac And uh does a few things to it and then passes it on to the high voltage Power supply, which is over here Which supplies the 12 or so thousand volts For the anode of the picture tube, which you can see that little suction cup looking thing We can see there is an led over there. Uh, that led Goes off when, um, there's a circuit in there Which basically turns the beam off if there's no signal because remember there's a Uh, this is a vector system. So it doesn't scan constantly the crt It actually just draws lines on the crt kind of like an oscilloscope And if there's no signal that would just lead to, uh, the Uh, the gun giving a spot right in the middle and just burning out that that middle phosphor Um, and this led goes off when that circuit goes off to detect that condition Um, and that, uh, results in the beam being turned off Now interestingly, there's a whole bunch of fuses here. There's one over there. There's one over there There's a bunch in the corner and you can see that there's actually two fuses missing That's not great So here is a view of the placement of the components on that board And this is oriented the same way we were looking at it There's that led over there Here are the two missing fuses. So it says f 100 and f 101 Let's take a look at the schematic to see what they do So here is the schematic and here are the inputs Now the interesting thing is if we zoom in To here, we see that f 100 and f 101 are the input fuses for 60 volts ac This is the x input over here and the y input over here Uh Without that 60 volts ac this thing isn't going to do a whole lot of anything Because for one thing, uh, let's see It looks like it gets rectified by a full bridge rectifier and then there are some capacitors and They sort of go all the way over here There's another fuse over there and there goes to the external High voltage, I guess But in any case, yeah, uh without those fuses We're not going to get any voltage at all. So That's kind of I wonder why they were removed Maybe, you know, just because when they put it in storage They wanted to make sure that it wasn't powered up accidentally. I don't know Um, but I'm gonna replace them and see what happens Again, I didn't see any leaky capacitors or anything. So It'll probably be okay Maybe we'll see Okay, so I received the fuses in the mail Now these are the ones that are missing. They're just two five amp fuses They're all slow blow type And these are the five amp ones, but there are there's also a one amp fuse here and a two amp fuse here These are already in there, but I figured that I may as well Get those just in case They blow that's in addition to all the other fuses that this thing takes. This is a seven amp one Here's a 20 amp one and here's the four amp one So that goes to that power supply over there So what I'm going to do is pop in These fuses turn the machine on and hope the fuses that I just popped in Don't pop apart pause for laughter Okay, so With the fuses in place now the only difference is that we have 60 volt ac coming from the power supply Going up. Let's see This wire here Up to that jack and over to this circuit here Which in turn feeds That high voltage power supply Which goes to the anode of the crt So Let's turn it on and see if things happen All right Whoa