FULL HOUR of Marshall Amp Repair Goodness - 1981 JMP Mk2 Master Model 100W Lead Head (2203)

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You asked for another amp repair or restoration video, well here you go... In this EPIC, hour-long amp video, we'll look at a 1981 Marshall JMP 2203 Super Lead 100W Master Volume Head. This is the last of the JMP line, which ended in 1981 when the JCM800 line began. This amp has a LOT of issues which we'll go over in this hour-long fixing, repair, electronics restoration extravaganza! A couple of the things we'll touch on include how to clean a square marshall lighted rocker switch, how to rebias the amp from EL34 or 6CA7 to 6550 tubes, and how to troubleshoot for shorts in the power supply. At the end, we'll demonstrate the tone of this beast with my Fender Telecaster.
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[@scottconner5401]

As the person who owned this amp at one time, and the person who had it modded the first time, this amp has changed so much since I had it. First off P.A.T. stands for Precision Audio Tailoring. The JB stands for Jeff Bober. Yes, THAT Jeff Bober. The amp originally was modded using KT88 tubes. When I talked to Jeff to have it modded I wanted basically the same mod he did on Brian Forsythe's (KIX) Mesa amp. The amp sounded amazing when I had it.

[@TheGuitologist]

It would be interesting to figure out the original mods he did versus any that came later.

[@scottconner5401]

Funny thing is I sold it to finance another one of his amps, a Budda Twin Master head and 4X10 cabinet. It was the first run with the purple faceplate but was wired like the original black faceplate ones.

[@adksherm]

Man this is a cool story! This is why I watch this channel. I am obsessed with different personal mods artists do to their equipment, I would (almost) kill to see some clips of this amp with the P.A.T. Mods working properly!

[@1980bwc]

@@TheGuitologistHere is Jeff's webpage and it has all his contact info. www.jeffbober.com/#2707

[@stepvanjoe3469]

Awesome to get a back story on things like this and hear about some of its travels thru its life

[@brentstewart59]

Oh how I've missed these amp repairs... Tele looks killer too Brad good job

[@TheGuitologist]

Tech vids coming back in 2020.

[@malcolmhardwick4258]

The Guitologist yeah it seemed you are very busy opening cool stuff people send you. Must be like your birthday every time the postman brings you something. But good to see some more tech stuff like in your earlier posts. I don't know know half the stuff you explain but before watching your videos I understood nothing. So I'm learning something!

[@scottdunn2178]

@@TheGuitologist I'm in no hurry, but still have a JCM 2000 DSL100 that blew a mains fuse about 12 years ago, and I just put it in storage rather than have it fixed. From your vid from last year, I suspect it needs the motherboard replaced, a cap job, and I'd like to put a (Classic Tone) choke in it. Can I get on a waiting list to have it fixed sometime in the future? You are familiar with this issue on these amps, and I'd certainly trust you to fix it. It's been down a long time and deserves to get working again. Regards, Brad.

[@Hulkhoagie1]

My favorite part about your amp videos is always at the end when you are testing them out. You have some serious chops my friend. Always look forward to hearing your playing.

[@TheGuitologist]

Thanks man. I appreciate you watching.

[@nezmustard]

It’s fascinating to me to hear the playing of someone who really understands the vibration.. ⚡️

[@yqwgjsg]

I’ve worked in electronics for 42 years. I watch you because the shit you do is way out of my experience. I understand the editing and other stuff but I could watch you solder all day long. I also love your commentary while you work. I’m an expert but not in tube amps so I have no criticism. You keep doing your thing because that’s why I subscribed. Just don’t think that anything you do is boring to us.

[@TheGuitologist]

Thanks for watching, Bruce!

[@davidhelmuth5707]

This kind of stuff is how and why I started watching your channel. Always great info. Suggestion: (if I may) would have been nice to see what it sounded like beforehand. Great video. Thank your for your time and effort. 🤘

[@TheGuitologist]

Understandable. In cases where I’m unsure what the problem is, I don’t like firing one up without looking inside. You just never know how hacked up something is going to be.

[@xthexadvantagex]

David Helmuth agreed

[@ringostarr4520]

I like to test the power transformer on really old amps before I begin the overhaul. At least bring up amp with variac & light bulb limiter in tandem. Just make sure light bulb not shining bright. If it lights up bright I float HV secondaries and check bulb limiter again. If I can find out the health of the transformer first it makes my repair run smoothly. If the client says he was running the amp prior to sending it to me then it also makes me feel more at ease about jumping right in to replacing caps. Bravo Brad on another great repair.

[@RockDrillSuite]

I agree, sort of skipped over “Step #1”, verifying the customer’s initial complaint of sound quality...

[@LitesLAB]

YES!!! Thank you Brad, I love the commentary vids, they are really quite good. For me though, nothing beats a sweet repair vid! Thank you!

[@denisohbrien]

came to say the same :)

[@slaphand5311]

I echo liteabong!!!

[@MrPnew1]

Me too, the repair videos are the gold IMO

[@bbmade]

Really psyched to see another amp video. Keep ‘em coming!

[@1dkappe]

Yes. Your best content.

[@umop3plsdn]

I agree with bbmade Brad CRANK em out

[@mickdebergerac1143]

You have one of the best down to earth channels on here! So watchable, love your commentary, "Fuck off man" ha ha ha… Don't ever change

[@SuperBossman9]

Brad, I like what you do and the way you do it. That’s why I watch these videos. I know enough to be dangerous but certainly aren’t a tech. I like the systematic/scientific way you diagnose and trace out these amps. I hope that when you stop making these videos that you’re still going to work as a tech, the world needs more good amp techs! I always enjoy your playing too!

[@spasmband]

I'm from ex-Yugoslavia. Like that tube :) and fun fact...just 60km from the factory that tube was made in :) BTW, excellent YT channel! Cheers ;)

[@PapaWheelie1]

I’m looking for a new set of tubes - you can grab the best!!

[@jutukka]

Unfortunately EI did run in financial problems a few years ago, didn't it. Sorry about that. So tubes are manufactured in Europe only by JJ in Slovakia.

[@mrbwa1]

That rant... I'm laughing so hard over here. I'm a photographer and that community has a good sized element of "elitist" attitude as well. Be you and do your thing.

[@vxidastronaut]

photog elitists are the worst of them all, if you don't have bokah you're a point n shoot noob, if you have bokah you're a noob that used too much bokah, if you have soft bokah you're too poor for a lens with crisp bokah, if you have crisp bokah you're a noob thats drawing to much attention to your bokah.

[@diemturner5755]

I don't think there exists a community devoid of know it all blowhards absolutely CONVINCED that they're the only demi-god on earth doing it the right way and everyone else is just retarded.

[@michaelholt3138]

That rant owns the Internet. 😂

[@Jupiter2ignite]

Oh god, the photography community is literally violatile.

[@shanejb2121]

A bit late to this comment, but you ain't kidding! This is an example I can relate to as I'm a photographer also, and I've bailed on more photography related forums because of that very reason. I've never gotten into it hard and heavy with anyone, because you just aren't going to change minds generally, but just the hypocrisy of some of the "snobs", as with any gear driven hobby, or profession gets really irritating. On one hand, you'll get these guys going on about shelling out big bucks, and having the absolute latest feature rich camera body with fantastic high ISO performance, and mega multipoint focus capability, incredibly fast burst rates, touch screen advances, processor speeds...the list goes on, but these same "Elites" will look at EXIF data posted along side, and are the first to come down hard on people "under them" that dare go outside the confines of near native ISO (usually because of lens/cost constraints), and full manual mode, and relied on these amazing features to their maximum potential in the posted photos areas on the forum. It's such a contradiction, and does nothing to embrace people coming into their own in the realm of their chosen hobby/field. At the end of the day...to many hobbyists, and pros alike, a good photo is a good photo no matter how you got there, just like here..a good repair, is a good repair. It gets real old and silly. Just like anything, there's always detractors, know it alls, and "Elites" who generally shit on anything, and anyone simply because it makes them feel better about themselves for whatever the reason. Brad's had more than his share of the same shit, and again...at the end of the day...who cares how he got there? It may not be "by the book" in some tech's eyes, but there's also a lot to be said for hands-on experience, and a hard knocks approach to dealing with certain repair challenges. I for one really value his approach. It's saved me some serious time and bucks.

[@jimbocarrino763]

Brad I could listen to you for hours man. You seem like such a genuine dude. Cheers From this happy Okie. 😁

[@jcm78]

“I’m a hack and an asshole now fuck off” 😂😂😂 couldn’t have said it better myself! I love both of your channels. Subscribed to both and binge watching during quarantine.

[@isoguy.]

Many years ago my old lab boss gave me some very useful advice that has served me well when dealing with so called experts, that advice was:- 1) Ex means "somebody who used to do a job" & a spert from a tap is "a drip" 2) "Everyone has an opinion but I'd doesn't make it right" 3) "The right way is the way that works for you and achieves the desired result" Brad Rocks 👍👍👍👍👍

[@69ssdroptop]

Brad, video's like this is what sucked me in a year ago and got me working on amps and to become a member of this channel. In the past year I've built a few amps, modded a few more, even done a few repairs. I've learned a lot between your backlog of video's and some of the other KZbinr's, most notably Uncle Doug (which you recommended). Keep up the great work, and I'll keep watching, and supporting the channel! Thanks again Brad!

[@TheGuitologist]

You're amazing, David. If it wasn't for dudes like you and the encouragement and support you provide, I'd probably have found another vocation long ago.

[@jo0cox]

I learned this from an old audio electronics tech from Switzerland named Rudy who worked for my father's TV and Stereo repair. The tech who preceded him Bud now an electronics engineer uses this too. For protection from a hi current draw from the power supply to prevent burning up stuff more for solid state but also tubes. You get a light bulb socket with 100 watt light bulb in series with the hot line with the AC Power plug also can help along with the Variac. If you get excessive current draw the light bulb will light up and it will current limit the AC Power and save unnecessarily burning up of new parts. I love your Channel I'm learning a lot. Thank You

[@jcmfer1]

i watched this at 1.5 speed just to get throw it a little faster. Then when you started doing the sound demo I was like "damn Brad can shred" then i realized you weren't rely playing that fast.. Love the leather pick guard .

[@LanceJean02]

Hey brad, I'm a truck driver and that guy you talked about bitching, in my industry we call a Super Trucker. A guy that thinks they know everything but in reality is a half-ass driver. Love your channel Brad

[@TheGuitologist]

Do you still use CB at all in trucking?

[@jonlennon3348]

I just want to thank you for introducing your head phones to us. I recently bought the same set you have the EX29's. The bass response of these are outstanding. Thanks again as I haven't been able to try a lot out but I took your word for it and I am super happy.

[@MrLeavemikealone]

When I built my jtm-45 clone; I omitted 3 of the input jacks and wired both channels together. The high/low input resistors are on a toggle switch. I also did independant bias adjustments so I can mix output tubes and dial in the bias on each tube. I put the measurement and adjustment hardware on the back of the chassis so the amp doesn't need disassembled. You brought back memories with using that decade resistance box to dial in which potentiometer was best . I ended up using 3 pots (one for each tube and one in series to tweak both in tandem).

[@marcseclecticstuff9497]

The best way to clean electrical contacts is to use an eraser. I use pencil erasers for typical oxidation, and ink style erasers for lightly arced / pitted contacts as they are a little more abrasive. For heavier damage, diamond contact files would be preferred (McMaster-Carr carries them). Many contacts are plated with ??? to lower contact resistance and resist arcing. Using any sort of abrasives will reduce/remove the plating causing premature failure so you always want to use the least abrasive methods first. Also, the smoother you can keep the surface of the contact the better. Arcs tend to initiate on pointy things and edges therefore you always want to minimize any scratches. Usually by the time you get to the point of needing contact files, the switch/relay is screwed and should be replaced anyway but it will buy a bit of time. Everything else you did was absolutely spot-on. You're one of the few techs I've seen that use the cheap wire strippers that fit any size of wire rather than the ones with half a dozen fixed sized holes - right on! Of course, I'm not a triple platinum certified super duper golden screwdriver award winning tech, just a guy that's been repairing electronic crap in my basement for over 40 years now, and an industrial tech working on CNC machines when I crawl out of my hole.

[@audiotechlabs4650]

You always show cleaning and or pin alignment on tube sockets!! Your service videos are NEVER boring! Let's just get that straight! We are so lucky to have you post this kind of projects! I am excite about this amp, can you Tell? Huh? Huh? I have a 50 watt version of this amp combo and I need to do what you have done on this one, so now I have a roadmap on how to do mine! Do the voodo you do so well! This one really hit home for me! It sounds the way it was supposed to! I was debating on which 6550s to put in mine, so now I know. Thanxz, brother!

[@sting1111]

I had that pcb in my 1980 I finally couldn’t take it any more and put in a turret board like the earlier models. It is now a dream to work on. I feel your pain working underneath.

[@Curtislow2]

My Dad was an ETN in the Navy, and he taught me to clean contacts like on an old auto ignition with a dollar bill.

[@goodun2974]

Curtis Lee, I haven't heard that one before; the old military techs and ham radio guys I learned from cleaned electrical contacts using a pencil eraser or ink eraser.

[@Rocknrollthor_norway]

You fixed the switch!! Most repair-shops would just replace it, but you did not even if it is very time consuming and by that a economical disaster.. at least for the growth of capitalism.hehe That is just awesome!!!! Demonstrating that it is easy to do for all diy folks is worth a lot more than the value of the time used to do it. You are a honest man that keep your mistakes in the videos, just so the audience can learn even more..that is something to applaud !!! Also, you are a brilliant guitarist, seriously!! Thanx!!

[@TheGuitologist]

I appreciate that.

[@chrissouthon7662]

Mate i have been watching for a long time , been playing for over 30yrs , you are a champion i wish you where in Australia to service my 30 + 100 watt heads , mate you are a great person and i truly love your content great job mate !!!!!!!!!!!!!!

[@ken952gtr]

The best place to draw the dc voltage for the effects loop is the cathode follower stage in my opinion. The 2nd gain stage is so hot for a 2203 style circuit, I can see why the bright caps before it were removed and 2nd pre gain pot added. The stock cold 10k cathode resistor on that stage is necessary between the 1st and 3rd hot stages. Great video by the way! You're a very good troubleshooter.

[@TheGuitologist]

Good point about the stock 10k and pot.

[@MegaTubescreamer]

always entertaining ,and amusing, but the priceless ability to fathom out and repair a jigsaw puzzle from a maze of lost connections like that, ,,and then play whats coursing through your veins, ,,those who can,,DO!

[@johnspina318]

Hi Brad....Having owned a JCM 800 2204 which I basically learned on and modded,and now owning a JMP 50 watter for many years,love watching the Marshall videos...Enjoying all your videos..Great stuff! Always enjoy your playing at the end of the repair videos!

[@justrightinmaine]

Just started watching this channel. LOVE IT. Brad is hilarious!! No idea what he’s doing but I’m addicted.

[@marcellinden7305]

For some silly reason while you were doing this restoration back to "stock" I had the thought in my techo brain that someone had made a bastard 100W Marshall bass amp out of it before it got to your bench. Way back in the late '80's I heard of many stories where this bass modification was done on numerous brands of amps but this for me is the first time I have seen the sorts of things that might/could be done to turn a guitar amp into a bass amp ... Good job on getting it back to its stock goodness...

[@MrDoctorsmith]

Hi Brad. The tone and playing is exemplary. Please keep the repair vids coming. Cheers from Western Australia.

[@raysmetaltracks6782]

"Lets flip this around and get a better look at the rear". Now we're talking... :)

[@azraelblick4117]

Yay, an amp restore video! This is what brought me here. "Well fucking congratulations!" -These are the comments that keep me coming back.

[@davidbrown4784]

Brad, I enjoy your videos. I am a EE, guitar player( not as profficient as you), and have worked on tube amps for years. It appears that Jeff Bober was attempting to transform this Marshall into more of a Mesa type amp. Anyway, from my observations, you have some very sound methodology, and technique for servicing and modding amps. I may do some things differently, but remember, electronics is not only a science, but an artform. Be assured, the naysayer, know it all experts have a lot to learn yet.

[@IplayMusic2]

Typically the losers that trash my videos have no videos on their own channel and I have to remind that THEY are watching MY videos and their videos, if they have any, aren't anything I would watch. I might not have the knowledge you have, but I enjoy watching your stuff. Thank you for putting in the effort.

[@mad7stringer]

"I'm a hack and an a**hole. F-Off" I want that on a t-shirt! Definitely entertaining and made me laugh.... thanks Brad :-)

[@bobmckenna5511]

One of the things I find interesting about your channel, I haven’t been a musician for many years and around the electronics industry, I’ll be at not in amplification directly is the danger of getting a used amp. So many people have made adjustments or mods, that adds a great deal of buyer beware to the field. Great work, I’ll visit you on Patreon soon.

[@TheGuitologist]

I don't have a Patreon, but thanks for the thought. If you want to donate to the channel, I have a Paypal link in the description.

[@kevan6781]

Nice work... Keep the repair videos coming. I don't think they will ever get boring!!!!!

[@SimonGotlieb]

Great to see another amp repair video Brad. I'm still pretty new to the amp building and repair scene and find these inspirational. Thanks a bunch.

[@leonardpeters3266]

I have also noticed every Hamsterhead that knows better. I've been doing tech work for 40 years and I consider myself plenty above average. But everyone is an expert. LOL. Keep on doing what you do I enjoy the videos. They are a fun romp and you have a great selection of all these different amps which makes it much less boring. I have never worked on Mesa amps, and after watching your vids, I never will. Thanks for that.

[@ChuckChrome]

The commentary on techs was priceless. Too funny.

[@ricktoney1551]

i think you are great man,thank u so much learn so much everytime,,and i like the way you present things interesting,,your humor is great..its like a spoon full of sugar with the medicine

[@peterdavies5358]

PAT test, can't imagine I'm the first to suggest this but I don't want to leave your wonderful content to read the comments yet. I realise you're resculpting you're algorithm but it's nice to see you're tech work again, much as SPF is a solid part of my week.

[@TheGuitologist]

Several others did suggest that, but that's not what it is. See pinned comment.

[@jjcollins]

Fantastic job restoring back to nearly original condition (original tone). Sounded great at the end.

[@kenjimac2211]

Awe man, was so excited to watch a new amp repair and get hit by an emergency. Great upload Brad! Thank you very much!!!

[@jcwear89]

Definitely missed the amp repair videos and loved this one 🙂 excellent work!

[@99gwest]

Damn that is a great Nirvana cover! And its really good see another amp video, seems like years since the last one!!!! Thanks Brad!

[@randolphcordell6380]

Hey Brad. Thanks for the Amp Repair video after a short drought of such! I know you put a huge amount of production time into your videos outside of the actual subject matter, so understand this is not a gripe. Love your channel. I always learn something.

[@davidwelch2438]

Arm chair quarter backs. I love it. Hi brad just wanted to say i love watching your videos they are always entertaining & I learned about cleaning pots & tube sockets from watching your videos uno plus a bunch of other useful information. So thanks for that.

[@guitfidle]

Man, I have that exact model amp from '79! Great to see this on here. I had mine professionally set up and rebiased for EL34s when I got it in '96- I got the good original factory Svetlanas with the test-tube logo. Sounds amazing still!! Thanks for a great video Brad

[@stevenwilliamdewitt]

I really respect your willingness to show your mishaps while repairing amps. These things happen in real life.

[@BrianKaplanUCNBG]

Nice Job Brad, it is great to see you get back to repair...great clean sound on a Marshall, Versile...

[@MarkEagleton]

The silent majority loves your technical stuff. You have guitar chops and tech chops. That puts you in the 100th percentile. Don’t let the haters bring you down.

[@94Shredder]

Honestly I have no interest in learning how amps work but I made it all the way through the vid. Very entertaining. Beast playing at the end 💪🏼.

[@Zeinzu2]

To my ears, this is the best sounding amp you've played on this channel (that I've heard). Also reading the comments, to my mind, this is the most interesting amp with the back story thats been given up to this point.

[@NitroModelsAndComics]

Clearly you do things very well Brad. Your attitude is perfect. Flex and move on.

[@TheGuitologist]

Thanks Robert. That's about all you can do. I don't even hold a grudge against the dude. We all say shit online we probably would say differently in person.

[@Twobarpsi]

Oh I need this amp!

[@45calypso]

Thank Christ, an amp repair video. I might even resubscribe if this keeps up.

[@craigalexander1489]

Watch all your repairs here in New Zealand. I,m 74 and worked on amps for years. You are very patient with the problems that occur. Only thing that concerns me is the ring on your finger around the high voltage. I got a nasty (240 vac) with my wedding ring. Have not worn it since. Also concered re wire wound resistor feeding the screens on output. I once had a difficult fault to find. HF oscillation, Outputs were KT88,s and they do not like WW on screens .

[@ArtGuitarLTX]

I don’t know anything you say when you talk about voltages and bust out your calculations....BUT....they are satisfying to watch. 🇺🇸🇺🇸🇺🇸👍👍👍😁😁😁 AND that Marshall sounds sweet also. Classic sound.

[@208414]

That amp has some nice tone at the end. Great work Brad!

[@cigarettesmokingman9471]

I use the low sensitivity input alot actually. I know billy corgan famously used it paired with his big muff. I really like the low input; sounds closer to a plexi.

[@MercurialToys]

These repair videos are my favorite that you do. I don't know anything about electronics, so it looks like magic to me what you do. How did you learn?

[@TheGuitologist]

Reading, KZbin, a stepdad who is an EE, and lots of trial and error.

[@markdalton293]

Hey Brad that ring on your right hand is the same exact ring my father has had for like 60 years , and he used to wear it as his wedding ring . my parents have been married for 60 years . I'm very lucky to still have both of my parents my dad is 82 and my mom is 77 .

[@madaxe79]

Hell yeah, love the amp vids, keep ‘em coming Brad. And i love the sound of the Tele. Awesome stuff

[@donrutter6765]

NOS Telefunken or Mullard preamps, Svetlana Winged C power tubes. The best choice for today. I see Brads playing style has improved dramatically.

[@TheGuitologist]

It has?

[@jens8014]

Wow this 2203 sounds very good! Just watched this for the second time😁

[@dennispennell]

Great video! I have been learning amp repair and building on my own and I get so much info watching you do these videos! Thanks!

[@kevin2960]

If you look at a couple different schematics, some of them did have a small capacitor on the first preamp tube to prevent oscillation. It was done after 78 when they had the high-gain front end like you have in this amp

[@jaycheek254]

Great freaking song during cap installation! I'd like to hear more of that song!

[@TheGuitologist]

The track is Lounge Act. Here's the whole project: kzbin.info/www/bejne/pmW3qIJ9idJ5e7M

[@downedaviator]

@@TheGuitologist Amazing. Man of many talents!

[@imagemaker5150]

Wow. I really enjoyed this video !! I am a guitar player but I would love to know more about how my amps work so I've been watching a number of "repair" videos on KZbin. The more videos I watch, the more I realize how much I don't know. Not sure if I ever will. I absolutely respect the amount of voltage inside the tube amps and frankly it scares me to think that one mistake could be your last. Great to see your process of troubleshooting and willingness to show that on your video. I look forward to watching more of your videos. Thanks so much for sharing !!

[@frankcoutts390]

Thanks for keeping it real,.I have Hi Watt 50 watt head's but my cabs have fane speakers.. never mind.. still sounds good. (1975)

[@garywordsworth9302]

Fane speakers are what you want with a Hiwatt head Sounds much more Hiwatt than through Celestion. Marshalls sound pretty good through 50 watt Fanes as well as Celestions But not the other way round, only exception to the rule is old pulsonic cone greenbacks.

[@frankcoutts390]

@@garywordsworth9302 Thanks for that..had them for 40+ years so not planning on changing them soon.. Maybe get a cab with something else in it.

[@SteveHacker]

YYYAYYY!!! Another fantastic amp tech video! This made my night! Keep these coming PLEASE! 😊😊😊 ... And just for my 2 cents worth, I LLLOVE the long videos. Show EVERYTHING as far as I’m concerned, even cleaning pots. I like seeing it all, and even if it’s not always “entertaining”, the things you have to SAY, ARE entertaining, so yeah, keep ‘em coming like this, man! Awesome! 😊😊😊

[@TheGuitologist]

Thanks for watching, Steve.

[@floatncoffee]

Guessing most people who critique your work are only half way through reading amp repair for dummies” they just throwing quotes for the book at ya to boost their own delusional self importance.. keep up the good work brad 🤘🏽

[@EdgarsLS]

3 certified fender amp techs disliked this video.

[@waynejohnson6594]

GOLD certified! LOL

[@ExStaticBass]

One of the things I've found works pretty well for keeping switches working is dielectric grease. It squelches any arcing from the switch opening or closing. That helps reduce oxidization from things like that and a lot of the carbonization that comes with it.

[@Dan79istheman]

Great to see an amp video Brad. Hope you’re well mate.

[@TheGuitologist]

Hey Dan! How are things? I hope you're escaping the fires! You ok? Family all ok?

[@joemorrow8411]

The Ampologist,,,great video Brad👍👍🎸 I loved the tech beat down 😭😭😭😭😭😭😭😭😭 😂🤣😂🤣😂🤣😂🤣😂

[@scotthewitt6047]

Back to the good old times thanks for the video

[@LitesLAB]

“Deoxit Johnny Appleseed” .... I’m still cracking up!

[@57Banjoman]

Don't fret about the d--- measuring -we love your channel-keep up the good work-cheers!

[@Mcqlfc]

Dude, anyone who bitches about you not showing cleaning pots should think that anyone capable of repairing an amp like you would be able to do that anyway. Anyone who doesn't know the workings of an amp would not be doing that shit themselves anyway. Great videos!

[@TheGuitologist]

Thanks Paul.

[@livewire6925]

As an electrician I naturally find this quite interesting. I was trained at board level repair, and learned tube circuits in high school. Yea! I'm that old, But What I find fascinating is the amount of regular folks who seem to enjoy this type of video. Great Job. You have some serious picking going on there. It would be great to see a performance video. I don't think I have ever seen a more efficient style of finger picking. You've got it going on Brad PS. Tolerance is Manly! People have the right to remain silent, but seldom DO!

[@discoshart]

Awesome video dude. You’re even adding suspense music for when shit starts getting real. Love it.

[@brandonc2859]

Funny thats my first priority too, flip em' around and look at the rear!

[@TheGuitologist]

I'm a back door man too.

[@Jupiter2ignite]

@@TheGuitologist I felt this comment

[@joshuataft5541]

@@TheGuitologist brad.bringing reality and humility to the world scince....well ..when he was born.lol. I love ya budy.your content makes me exude the passion I had as a kid and almost lost. Now im35 and am getting souch better due to awsome content like this

[@tankthelord1178]

Nice one Brad. Good Job even though you didn't record putting the 2 or 3 screws back when you were putting the board back in.... lmao.

[@chaseth]

Thanks Brad. Watch all your videos. More amp repair videos!

[@guitarpodcast]

Lounge Act is one of my all time favorite cobain songs.

[@TheGuitologist]

That ending of that song when he's just wailing on those vocals. Gives me chills every time.

[@jochemjonker3362]

A nice and eye opening video,especially the cleaning of the "Rocker Switches",so now it's "Brad the Rockerswitchcleaner". I was a little surprised about the 2 black capacitors, bridged to the group of 4 main capacitors. I never saw them before on that place(own a 1978 2203 that has to be rebuild and thinking about servo pots installing and making a 2 stage MV,pre and post phase invertor stage),but you found out,that they had to removed again. About the controlable different preamp gain stages,reminds me to Burman Amps,like the 502 model:3 controlable pre amp stages witn a MV control. And you are right,on lots of people critizising on technical aspects of repairing.A lot of electronic technicens are likely autistic in the way they look about how to work.

[@amitavasen4165]

I am also in a servicing job like you from India. Your repairing techinic enlightent me. I want to see some solid state amp, because tube amps not selling here.

[@SkyscraperGuitars]

I enjoyed the play through at the end just as much as I enjoyed the amp repair. Thanks for bringing us along Brad!

[@cassvirgillo3395]

Hey Brad, The Guitologist, very good video, nice fix. For a newb like me, going in to more detail, like you do, really helps to learn what is going on in the circuit. You, Uncle Doug, El Paso Tube Amps, All American Five Radio, Paul at Mr. Carlson's Lab, my top go to channels, your in good company my friend. I hear ya man. All the best to you and your family, C. P.S. I have a 1965 Gregory Mark 1, I know you have a video on KZbin, would you consider going over the circuit in a bit more detail, it would be much appreciated, your call.

[@TheGuitologist]

Eventually I’m sure I will. It’s a series filament amp.

[@paulkielt9301]

Those Ei 6CA7 sound really good. Unfortunately, it's rather impossible to find some nowadays. On the other hand, if I were you I'd also replace those cheap 1N4007 rectifier diodes with some FREDs. To me that kind of an amp deserves that!

[@SeanKerns]

I can honestly say I've not had one of those Marshall rocker switches go bad before, nor have I seen the inside. But now that I have seen it, it looks flimsier than I expected. Most of the rocker switches I've run into were just a plastic rocker than worked a slide switch. So, I learned at least a couple of things today.

[@DeadKoby]

That amp was your weekly challenge. Most of my fixes lately are very straightforward, so it's not much of an adventure.

[@burnbacktime]

Careful what you wish for. The next thing you work on could be a complete clusterfuck. 😁

[@TheGuitologist]

Yeah man, here lately that seems to have been ALL I get are weirdos. They come in bunches. I had to take a break after a couple that got out of hand. Steals a bit of your sanity.

[@DeadKoby]

@@TheGuitologist By comparison, my latest was a Vox AC30C2x that wouldn't come off of standby, and produce ANY sound at all. Turns out the gent had played the stock tubes until they totally died, and the fuse for the HV gave up the ghost.... Fortunately Vox/Korg used a 500ma fuse on the HV, and nothing else bad happened. That's what I mean by "straightforward fixes."

[@augustisaacson7903]

The JB might be Jeff Bober at Precision Audio Tapering. Jeff was the guy behind Buddha and later East amplifiers. I have a 74 JMP that he added a half power switch to, similar signature✌️

[@targaray]

Brad, Have you ever considered showing us how to step by step clean the controls? Just wondering...

[@targaray]

lol

[@jamesmaxwell5415]

YOU DID NOT PROPERLY SHOW SCREWING DOWN THE BOARD!!! (I really love your channel...especially SPF😊)

[@tankthelord1178]

I noticed that too. Shame on Brad! That's what I say! lol

[@kevmet84]

Interesting the rocker switch cleaning was.