Fixed The Chorus Effect On This Guitar Amp.. And Snazzy New Grill Cloth!

ladies and gentlemen this is Joe's classic video games back with another cool guitar amp repair video for you this evening now we're way off in the weeds here but normally on this channel we do arcade game pinball machine or jukebox repair videos but on the weekends like today you should be viewing this on a beautiful Sunday uh I've been doing a few videos of radios and clocks and things like that that I'm interested in I call it amateur repair time and the last couple videos I've done on a guitar that wasn't working and then last time we looked at this old crate amplifier um that's the frame of it there that had a little problem so if you didn't see that video you might want to check it out basically the issue is the guitar amp Has No Chorus the chorus doesn't work on it and we looked over the schematics and and we think we've got it narrowed down well I've got my chip in so we're going to see if we can fix it finally on this video and if we if we get it working right I'm going to uh see if I can fix the speaker Grill cloth we'll see if we can do that too so I'm going to very quickly go back through the schematics to show you uh what we think the problem is but if you watch the previous video you'll see a more detailed uh view of the schematics now if you only like if you're only interested in the arcade game pinball machine or jukebox videos we'll see you back here Tuesday so uh see you then but the rest of you if you're interested in trying to see if this thing ends up working um stay tuned so here are the schematics this m this amp is a GX 30m guitar amp and it is made by crate it's a little bit older one is made in the United States probably in the late late 80s well sometimes in the 80s I would guess you might be able to tell by the serial number but I don't Tony did the sound test Tony the chorus stopped working eventually buddy um I don't know if there's anything that can tell oh you know what can tell us when it was made the schematics so the original schematics were made in ' 93 and they were revised up to 97 so this would be sometime in the 9s likely says originally issued 1992 I would have to think that's when the the first version of this came out okay so very quickly here's where the let me zoom in because it'll be better quality here's where the guitar plugs in or anything plugs in this is the clean Channel and so basically you run to here where it has separate controls for all of the uh uh mid low high and then the level which is basically volume right and it runs into this preamp here which is a TL 74 all right so that's the clean Channel now if you hit this switch it changes the channel to this channel so now the guitar plugs in here goes through the first preamp and then up to here this is the overdrive channel right so it does more processing to it has its own level control and comes down to the same place where it connects to the TL 074 so clean Channel overdrive channel one of the two is always on once it goes through that preamp or that resistor or that cap once the signal passes from here to here they then add a couple effects to it so one is Reverb the reverbs working fine so so it runs through here runs through some little audio connectors into a Reverb tank with springs in it I guess and then there is a level control here the Reverb control so if this is on zero basically you just won't hear this although it will still be being created right so it's going to make that whether you like it or not so there's always Reverb you just might have it turned down so you'll in that instance you would just hear the clean Channel or the overdriven channel you would not hear the Reverb if you turn up the Reverb knob you would then hear the Reverb and the clean channel uh and the overdriven channel okay alsoo instead of reverber in addition to reverb the signal goes this way into this chorus section this is what isn't working so we figured out last time that the way they make it work is they have a couple preamps over here I'm just calling preamps they might be a slightly different you know idea but basically they have this and some resistors everything's wired in a certain way that it creates a signal okay there is a depth control and a rate control those connect all of this is separate it's its own little thing and it connects to this chip so this is an MN 3101 it has three inputs ox1 ox2 ox3 so those three inputs create a clock signal so this chip passes two clock signals and a voltage to this chip the voltage is constant if the supply is -3 the voltage would be -12 okay RS is a little high RS is like -5 and this voltage is like14 but it's always one volt higher than the supply voltage of these two chips this is called a BBD chip a Bucket Brigade device and so what happens is the signal comes in here to this input the two clock signals control it and control basically how this delays this signal and then it passes out the signal as an output after it is delayed according to the two clock signals so our problem is there's no output here so this chip is putting out the two clock signals and the voltage which is all this needs so this chip is getting an input a clock a clock and a voltage but no output so the theory is this Chip's bad so we'll see it's an obsolete chip but it's such a cool chip that they made new ones so it's an MN 3007 we think it's bad if it were to work it would send out an output which is delayed from the original signal uh and if you turn on the switch for the chorus you would then get it so you would get let's say just your clean signal you would get your clean signal plus whatever Reverb you have turned on right which would would be at the same uh time basically as the clear signal but the chorus would be delayed slightly which gives it the chorus effect if you had the chorus turned on and this chip was working right so what we need to do is remove this chip and put it our new one in so let me show you the new chip that I was able to order all right so I ordered it from this place called cabin Tech and then they sent me a guitar pick boy that's cool I like it a lot and then here are the new Chips I ordered two of them they're the same they're both that same chip the 3007 and I just order two just in case I screw one of them up and it is made by xvive so xvive audio has made brand new Chips it's a reproduction of the original chip which was made by pan Sonic maybe so they they have actually since these are used in so many uh guitar pedals and things like that amplifiers they have actually reproduced that chip so these weren't that expensive they're like $11 or something so I bought two of them I would have bought more if they were cheaper but the only Reon I bought two was in case I screw one up but I shouldn't all right so here is the amp there are the two chips you see the 3101 there on our left and then the 37 there on our right we think that one's bad everything else seems to be all right so I'm just going to carefully desolder that and then I'm not going to put a socket in usually I do but um it's only eight pins for one and then two you know you're going to have a lot of Bas and stuff on this this is actually going to be vibr vibrating from time to time and it's portable it's meant to be moved so I don't really want to have to go back in there in case it starts working its way out of the socket so I'm going to solder it in very carefully and hopefully do a good enough job that it can be removed um in the future if somebody needs to work on it again so let me unbolt this and then I'll see if I can get it out of there okay I got it swapped out and I think we've got [Music] it so this is the [Music] rate [Music] that's the [Music] depth all right so I think that fixed it so that chip was bad it happens so if you need one XV audio works great all right so I'm going to put it back together and then we're going to look at the speaker baffle so here is the uh baffle as I found it so I bought this online and had them ship it to me used of course and um you could see in the pictures that it was pretty damaged which doesn't really matter but I'm going to see if we can replace this make it look a little better now one thing I wanted to point out if you look at how they did it it was never straight so see this like you can follow this black line here I guess that's it up there so it was crooked the entire time that it's been installed the side is pretty straight but it's not perfectly straight either yeah so this part is off maybe a quarter inch this part is off almost a half an inch I mean it's not even close to straight so if we get it pretty straight it it'll look a lot better than this so I'm going to uh take the speaker off and set it to the side so I don't poke a hole in that precious paper uh uh cone and then I'm going to start taking all these staples out and I'm going to do it with the my little chip lifter you know this is great stuff here this is a weha from Germany look at it doesn't that look like the perfect thing to remove Staples with I bet it's going to go quick so we going to take all the old off all right so I was able to get it off this is actually where the little crate logo goes on the front right and so you can actually get tons of speaker cloth they make and this is pretty good stuff it's pretty stiff so they make reproduction speaker cloth all kinds of it it's almost it it kind of feels like a scrubbing pad or something right um this was a little cheaper this was like this is almost like that stuff that like um uh picnic chairs are made out like the chairs you put out in your yard or whatever are made out of this stuff's a little thicker this pattern is a copy of of one of Fender's patterns so everybody wants their guitar to look like that so they make this stuff by the boatload I ordered this from Parts Express and it's cheap this whole thing was like $10 or something right so um I and you just get it in this size we're only going to use a little bit of it and then I'll have a bunch left over I might end up having to put it on some radios or something I've got a bunch of radios with the grill cloth all screwed up so on some of those it probably look good but um and on the Fender amp at least the yellow line goes left to right um so I'm going to instead of up and down so I'm G to unroll it a little bit we'll lay the baffle on it and figure out how we want to cut it okay so I have cut it out little uh Dave cooler reference for you there um and I kind of centered it and I got the lines to kind of line up so it's the same on this side as it is this side and it hits the line the same and on this side it's halfway through one of them and on this side it's halfway through one of them and got it all kind of straightened out and I pulled over a little part just to make sure it's going to be fine so what I'm going to do now is I'm going to get a heat gun and I'm going to heat it up just a little bit cuz this stuff is like thick but I'm not going to go crazy with it we're just going to get it a little warm so it's you know it's agreeable you see what I'm saying all right so I heated it up just a little bit and then I took I've got a staple gun here and I'm using quarter inch staples because I don't know know that an electric staple of that caliber could drive anything much deeper in this OSB right but quarter inch should be plenty um you can see I did this one first cuz I didn't push it all the way down right so I did two or three of them to tack it in the middle when I had the ends lined up how I liked it and then I went across to the other side and stretched it as hard as I could and tacked it there and did a couple more and then a couple more over here and then a couple more over there and a couple more over here and as I I was stretching it towards the end right and so I've ended up where the line along the end is still straight uh or reasonably straight and so now I'm going to start in the middle on the side and do the exact same thing and try to make sure that I keep these I try not to distort these lines too much you know you want it to roll over exactly along a line if you can help it so that it's not all wavy looking all right so I got the Staples in all the way around the edge Edge and on the corner you just cut it straight this way and straight that way and then cut a little 45 and then try to hold with the Staples I got it a little too far away there but you can put a little Staple in each end too remember all this is hid inside of the thing so you would cut like right there and right there and then trim down what you've got left all right so I was very carefully able to find the original hole that the little logo was on and poked a little hole in it lined it up screwed that one in and it made that one line up so uh what do you think pretty good huh okay so now we got to put this on it starting to get some of the trim going huh I think it looks a heck of a lot better I got it pretty straight it's not perfect but it's pretty good it's not bad for what it is starting to look like a finished product I put the speaker back in it you can actually see it if you look carefully I cleaned it off a little bit very carefully with a whisk brush um and I'm going to throw that in the trash you've seen it enough you you don't need to see it anymore in this video so I'm going to go ahead and throw it away you saw it happen you know that that was how it looked uh and I'm going to take this home and uh install it back in the amplifier then we'll have the best looking crate amplifier in the world maybe all right folks so that's how it looks with the new cloth in and everything back together I think it came out pretty good but yeah that's a you can tell that's like a fender look but I think it you know it's not so obviously Fender that I think it kind of works with it you know what I mean so I am not a great guitarist but I'll play a little bit just so you can hear the difference and then hear the chorus work so this is it clean [Music] um and you can change all of the um you know we can turn it way up piss off the neighbors [Music] [Music] um that [Music] that's so it sounds pretty good I think okay so that we'll switch from clean to Overdrive got it turned down whoa whoa I've got it on Two And that's pretty damn loud I don't know if I should play that I mean let's try with the let's change the shape a little [Music] [Music] bit all right so now uh we'll put it back on clean and we'll turn the Reverb up [Music] okay and I will put it on overd Dr with the Reverb [Music] up so the Reverb alone just sounds awesome okay so we'll go back to clean and we'll turn the Reverb back down and we'll turn up just the [Music] chorus if you turn the raid up it makes it sound kind of weird cuz it's just going too fast it would help if I remember what key that's [Music] in I don't think the rate that high is really all that useful if you slow the rate down a little bit it sounds [Music] better [Music] okay so then with the oh [Music] so you can hear the chorus doing its thing and if you get the depth down lower the effect kind of goes [Music] away [Music] you're supposed to bend that farther it should go up like a whole [Music] note and it's higher too it's supposed to be [Music] like where the hell is it [Music] you get the point so the chorus is working pretty good so I think if you put like overdrive on and your Reverb and the [Music] chorus [Music] and you've messed with your tone a little bit on your [Music] guitar so it's a nice little amp I like it I think it worked out pretty good I can't remember how to play some of these old songs [Music] though so there you go I think we got it fixed it's a pretty noisy amp though to be honest which I don't really care stuff like that doesn't bother me on the pinball machines a lot of people a lot of times people complain that the lights make noise and stuff I couldn't care less so it's got a little hum in it right now if I turn this overdrive way up you'll probably hear more of it yeah I guess that's normal but even with it clean I mean it's pretty [Music] noisy so if that drives you crazy you'd probably need to replace all the caps and then it would still be there a little bit and it drive you a little more crazy so but I'm real happy with it I think it turned out pretty nice so there you go I hope you enjoyed it I'm glad we were able to save the thing I think I'll be able to use it now as a little practice amp you know for whenever I start my rock and roll career you never know people it's never too late you know I'm still a very very young person so uh who knows you may see me on the cover of uh country music today or something so leave your comments down below did you used to have one of these beautiful crate gx30m huh huh uh uh that little chip that we replaced ended up doing the trick and uh besides that everything was good so if you've got one of these it probably still works just fine I like it and I got like I said I got the speaker cloth from Parts Express and I think it's pretty quality stuff it's pretty tight I didn't get it like super tight I heard people online saying that if you really get it super super tight which takes a lot of effort anyway anyway that it sometimes it'll rattle whenever you play but you know again I wouldn't really mind too much so all right there you go we will see you on the next video hey don't forget to check out my brother Donnie my brother Donnie has his own channel here on YouTube and I'm over there with him on his channel usually helping out and uh but we'll see you back Tuesday with another pinball machine repair video we are doing the Playfield on our gol airport pinball machine and it's been going swimmingly well so we'll see you Tuesday with that and this has been amateur repair time