YAMAHA's Professional Amp

Рет қаралды 181,099

Ай бұрын

UPDATE:
So I’m running a 3-part LIVE workshop that takes us on…
A Time Travel Through Vintage Electronics.
We’ll rewind the clock, dive into the tech of the times…
(and study the very history of how things were broken and repaired has evolved)
The workshop is coming soon, but if you're reading this then you're in luck (or not)...
And there's still time for you to sign up using the link below:
www.menditmark.com/mend-mark-...
The workshop dates are mentioned in the link above too.
---
Mark rebuilds a battered 1976 vintage Yamaha P2201 Amplifier. "There's a fault with one channel", they said.. But who took all of the parts out?
Special Mention to Lighthouse UK Ltd, who provide Mark with some much required support for the Label Printer (see last 5 minutes of this video for the full story). Should you contact them, make sure you mention the channel!
www.lighthouse.uk.com
For the super-fans, you are welcome to support Mark, and get behind the scenes peeks on the Patreon page:
www.patreon.com/MendItMark

Пікірлер: 865

@MendItMark 29 күн бұрын

@MVVblog 28 күн бұрын

I signed up immediately! I didn't understand a word because I don't speak English but I'm sure it will be great!

@haroldbekaroe4556 28 күн бұрын

? M)) p)ft

@davidurk3229 27 күн бұрын

I signed up, can't wait. Greetings from Milan, Italy.

@briangoldberg4439 27 күн бұрын

Is it going to be on youtube, or is this going to be somewhere else like Twitch or something?

@FUNKLABOR_DL1LEP 27 күн бұрын

of course, for me in German 'VE99' and 'curious marc' is nr 1, than 'mr carlsons lab'..

@Mcqlfc Ай бұрын

Is there anything that you don't look forward to more than a new Mark video? Keep them coming please!! Also, it would be great to hear how you gained your knowledge. Electronics, chemical, mechanical, you know it all!

@georgedyson9754 Ай бұрын

Absolutely - go straight there when there is a new one!

@davidroberts3429 Ай бұрын

Totally agree!

@TheAmazingprd Ай бұрын

I'm so happy when a new video is uploaded!

@matthewm3927 Ай бұрын

I agree!

@wirdy1 Ай бұрын

I don't know if anyone else notices the superb editing & audio on Mark's videos? Just the little touches like changing the sine audio level as it's varied on the amp, sublime.

@malcolmclenton1663 Ай бұрын

I recognise that amp as one from Birmingham Repotory theatre. It came into where I was working at hte time for service. The initials JD belonged to John Deakin one of the service technicians. A long time ago in the seventies. He has since passed away sadly.

@PaulaXism 29 күн бұрын

I knew John quite well. He did most of the large heavy audio equipment repairs in the midlands. Nice guy, always helpful. Sorry to hear of his passing.

@bsimpson6204 28 күн бұрын

"A long time ago in the seventies. He has since passed away sadly." But his amp lives on, we should call it 'John's amp' serviced by Mark

@Mnelissen1968 Ай бұрын

Let's get this man some more subscribers. There are a lot of channels that are really crap that have more subscribers than he does. Mark is the real deal when it comes to repairing electronics! This man takes so much time and effort in putting these videos together. In such great detail, next to nothing skills and when something is not available, he makes it himself. Mark is such a nice guy, great knowledge and very entertaining to watch. Every time he puts out a new video like this, you can take your popcorn and drinks and watch this from start to end like you watch a new episode from your favorite series. Keep up the good work Mark, great to hear you move to a new workshop.

@che1602 Ай бұрын

Totally agree. I’m sure he’s a guy you could have a drink and share a laugh with too.

@andymouse Ай бұрын

Yep, I can think of one with double the subs and I don't get it !

@RegiPavan 29 күн бұрын

Spot on! Let's get him more subscribers

@user-mv5bu2kk8b 29 күн бұрын

Like watching a whodone it on telly

@SlartiMarvinbartfast 29 күн бұрын

I couldn't agree more - unfortunately due to the stupidity of the vast majority of the human race most are drawn to the loud, flashy dumb stuff. This of course applies to all walks of life, not only KZfaq videos.

@wirdy1 Ай бұрын

Fabricating those transistor covers is just next-level refurb; not only painting, but matching the text. Awesome.

@ZiggyAndTheSpiderFromMars 29 күн бұрын

Mark has the skills and tools for every problem. He even has a labeling machine for this very purpose that cuts out the warning labels per spec.

@OC35 15 күн бұрын

I would have used TO-3 plastic covers!

@exiledscouser919 Ай бұрын

Mark exudes confidence and competence. You know he’ll sort this disaster

@prs24328 29 күн бұрын

Dare I say that Mark's videos are on the edge of being therapeutic to watch! Thanks so much, Mark!

@sobolanul96 28 күн бұрын

He is such a positive guy!

@rokkenbole 26 күн бұрын

Absolutely! I 100% agree!

@bobgrob4 26 күн бұрын

He's in my top 3 list here on YT for sure. He should have a million subs and his channel will grow and grow if he stays with it.

@bobgrob4 14 күн бұрын

it's approaching an addiction for me. I love this guy. Every aspect of his uploads are excellent.

@davids2448 Ай бұрын

No surface mount items, no chips...ah the joy of components that can be examined, tested and replaced without magnification!

@alfsmith4936 27 күн бұрын

Built when amps were designed to be fixed before tomorrows gig.

@mpmyprojects6687 29 күн бұрын

Mark shows us a level of craftsmanship that many ‘repair shops’ don't even know exists.

@CasperHP1977 Ай бұрын

The sticky residue on the cables is from the smoke, not dry ice 😁 . The smoke fluid is water and glycol, and the glycol is the thing making the smoke white. If the smoke is used in a nightclub without any ventilation, the glycol will condense on stuff. A typical fault on movingheads is the condensed glycol on the cables inside, making the dust stick on them, and making them brittle.

@BTW... 29 күн бұрын

Imagine what it does to ya lungs.

@app0the 27 күн бұрын

@@BTW... and yet some people are now carrying around pocket sized smoke machines to suck on them at any free moment they have

@jpdemer5 27 күн бұрын

Glycol is in "vape" smoke. Doubt there was much of that in the '70s and '80s. I think the sticky goo is phthalate plasticizer in the clear PVC tubing, which gradually sweats out to the surface (making the tubing itself gradually become more stiff.) That's why it's only the tubing that has sticky crud on it. It's an easy-to-replace item.

@alfsmith4936 27 күн бұрын

If it was gigged, it's probably real smoke.. I replaced the pickups in a Strat I used to use before smoking bans last month and it still stunk of cigarette smoke.

@haakonness 22 күн бұрын

@@BTW... it's also used in inhalers

@ronmelanz2820 Ай бұрын

Mark is one of my favorite net personalities. Straightforward with no mucking about. Can't wait to see the new digs.

@bobgrob4 26 күн бұрын

@OldFatBubba many of these techie type people are kinda grouchy. Mark has got the best, most refreshing personality that Ive experienced. His channel should be in the millions of subs. Its money in the bank when he uploads a video. Hes the best by far. One of the main reasons I do KZfaq.

@jooch_exe 29 күн бұрын

This is more than just mending. To see someone taking care to recreate missing parts from raw steel is truly a labor of love.

@hubbsllc 27 күн бұрын

And a power amp is ready to re-enter service! Power amps are among the most useful pieces of vintage tech there is. Even a really good one from the '70s or '80s, once properly sorted, is really good even today.

@RickMahoney2013 Ай бұрын

You won’t find anyone as professional as Mark he’s the best !

@richards7909 Ай бұрын

Can we all admire what appears to be masking tape with “nope!” written on it :D

@marcse7en 29 күн бұрын

"Nope!" ... We can't!

@user-mv5bu2kk8b 29 күн бұрын

I do that at the Cooker before the wife begins

@michaelfuller34 29 күн бұрын

I bet if you sent Mark a shoebox and told him it was a McIntosh amp, you’d get a McIntosh amp back in 10 business days 😂

@rayofcreation3996 28 күн бұрын

😂😂😂

@alfsmith4936 27 күн бұрын

I'll be sending him my Dumble next week then.. I don't know why it's not working. It's very light too..

@bobgrob4 26 күн бұрын

LOL!!!!

@bobgrob4 14 күн бұрын

I can just hear him say, " some parts were missing so I had to improvise with a bit of wood and metal work here in the workshop." LOL!

@weevie833 29 күн бұрын

The abject anxiety I get watching Mark completely dismantle these old buggers is offset by the dopamine blast I get when it comes back together and actually works.

@Barbarapape Ай бұрын

A great end to a hot and sunny weekend. I like the way Mark goes the extra mile to ensure that all repairs leave in a safe condition. Best of luck moving to your new workshop.

@Jacob.Zonneveld Ай бұрын

Genuine shock when Mark said he'll be moving shops, I thought he loved the clutter! Extremely organized, however the lack of space is only somewhat evident(;

@ps-ib6ct Ай бұрын

A sunday with Mark! Splendid

@IqbalKhan-hc1hv Ай бұрын

It's better to watch you working than to watch a Hollywood action movie. Lots of love and regards from Pakistan. Stay blessed.

@TheAsrgrant Ай бұрын

Good afternoon Mark! I can relax, cuppa tea, and watch your great video!

@markfx12 Ай бұрын

Mark, you make these repairs look so easy! The missing parts is simply amateur workmanship and unforgivable.

@drummerhammar 29 күн бұрын

I think when the former repairman found out that the blown transistors were out of production, he didn't bother to look for replacement, like Mark did.

@PaulaXism 29 күн бұрын

@@drummerhammar It was very different 25 years ago. We don't appreciate how easy it is to source parts these days. I had to basically give up on quite a few things back then because parts simply were not available.

@edmaster3147 28 күн бұрын

Mark's a gentleman leaving out displaying his underlaying knowledge and the judgement, though he sometimes subtle hints of what he thinks about other techs' solutions. In this case one cannot know the reason behind not finishing the repair by the previous tech, I know just to well that sometimes projects of gear you don't really use gets pushed behind.

@jpdemer5 27 күн бұрын

Also possible that the amp was cannibalized for parts (those rare transistors in particular).

@alfsmith4936 27 күн бұрын

Back in the day, If it works for tonight's gig, it works until it needs fixing again.

@arieschouten1326 Ай бұрын

Mark, You've even made it to the Netherlands. I find your videos so informative and well-explained. It's just a positive therapy to watch you while doing the work you perform.

@michaelalberson126 29 күн бұрын

Not only are you extremely talented in electronics but you also understand how to make things from sheet metal and how to measure correctly. Absolutely awesome and I appreciate your KZfaq channel one of the best around.

@markboon341 Ай бұрын

Mark, your attention to detail and general knowledge and professionalism never ceases to amaze. Good luck in your new workplace

@jeremiahchamberlin4499 28 күн бұрын

Your cheerful confidence seems born of experience and a good attitude. Most of us would be scared to tackle the projects you take on in stride.

@rccc5806 29 күн бұрын

Meaning to say this for a while. Whoever designed the sound for your videos is a genious. The precision, but also calm inducing.

@TronicGames 29 күн бұрын

Cover fabrication at the end was just amazing. Really rooting for this channel to grow big.

@neph3129 Ай бұрын

Excited to see the new workshop!🙂

@ciogon 21 күн бұрын

i watch his videos only for pleasure..this guy seems very humble and nice...

@KP-nd3bx Ай бұрын

Looking forward to seeing the new workshop.👍🇩🇰

@pantelisEVs Ай бұрын

Absolutely amazing repair! You can't admire more that these amps never get old! Thanks Mark

@crumplezone1 Ай бұрын

I am a hard man to impress but you impress me very much Mark

@user-mv5bu2kk8b 29 күн бұрын

I'm sure that Mark is not that wayl inclined

@toolsarecool Ай бұрын

He’s Mend it Mark AND Bend it Mark…!!! those covers are awesome! 👏 🔥

@andrewslade7867 Ай бұрын

Mend it, Bend it and Print it Mark!

@alphabeets 28 күн бұрын

He’s so clever. It seems like there is always something new to learn in each video.

@liquidco2 5 күн бұрын

This channel is criminally under appreciated, when you reworked that motor a few videos ago that hooked me in.

@MrTylerStricker 19 күн бұрын

I really like how absolutely every single thing that was done in this repair is left in the final edit. Really gives you a good idea of what's happening that a lot of other channels don't provide

@NFLineast 29 күн бұрын

I'll miss the old workshop for sure, Mark. Quaint. Calm. Homey.

@nomadben 29 күн бұрын

This is my first time coming across your channel, and what a pleasure! Your repairs are so thorough, and your positive attitude is a joy. It's always satisfying to see old equipment being repaired instead of just thrown out. Excellent work.

@Plons0Nard Ай бұрын

New workshop coming !!! Interesting Mark. I prefer to keep things as they are. It is difficult enough to keep track of where I put stuff 😄

@batmandestroys1978 Ай бұрын

It feels like Christmas! Mark has turned up!

@PeterHughes-ne9wz 29 күн бұрын

I know sod all about electronics but I'll happily sit watching Mark carry out his repairs, a true craftsman at work! Love the intro music too! Look forward to seeing the new workshop. Thanks Mark!

@bobbicaroldavies494 Ай бұрын

Thanks Mark. Real entertainment on a sunny Sunday afternoon in North west Germany

@fiddleywest3778 Ай бұрын

This is some serious workmanship. Mark you are amazing.

@shaky3142 25 күн бұрын

I mostly have no idea what you are talking about but your style is very engaging so I keep watching

@UNCLEBGA 29 күн бұрын

Those transistor covers were such a clever idea. The printer trick was clever as well.

@IanScottJohnston Ай бұрын

New workshop?.......looking forward to it!

@jpdemer5 27 күн бұрын

How many of us would take one look inside that thing, and say, "Sorry, no way this can be fixed"? Congratulations on the new shop . . . hope the cat likes it!

@JonDoe-zi3mh 29 күн бұрын

That looked like a right basket case, but you sorted it all out very confidently and professionally. Love these videos and the "professional" gag at the start of this one. Would love for you to feature the cat more often!

@privateuser-xp4nz 29 күн бұрын

I'm kind of sad that you're moving to another shop yours has such honest character

@brendanbarbour8568 Ай бұрын

Thorough job Mark as always, you didn't cut any corners...fake parts are a real problem...came across it when trying to source some 2SC2922 and 2SC1905 Sanken devices....The real problem is not finding modern equivalent devices that can deliver the power, but can match the Early Voltage characteristics as well.

@graemeyetts3465 2 күн бұрын

The making of the heat sink rail covers was great alone. Excellent video and skills in a fun presentation.

@generaldisarray Ай бұрын

Outstanding work Mark, just outstanding. A master of many, many talents. I think I'll miss the current/old workshop, it has such a one man in a shed vibe, a bit of a cosy warm feel to it. However, I can't wait to see the new workshop, you might even have enough space to swing a cat and have a bit of elbow room.

@2sc458 Ай бұрын

That is the sibling of the P-2200. That was a gorgeous amp with Awesome meters. Its downfall was, Yamaha made custom meter drive amp IC, an IG0.... something or other, that tended to fail and render the meters useless. It had a big Toroid transformer for mains. I never have seen a P-2201, but I can guarantee you that Yamaha would never leave their output transistors open on external heat sinks. This is a case where some lame servicer lost that stuff.

@tazmaniachill Ай бұрын

Sunday is complete… cold beer sitting in the garden with Mark… 🎉😂

@brucebuckeye Ай бұрын

Mark, you go after these complete basket cases! Once I saw all those transistors missing, I was yelling TRASH IT! You are amazing!

@darkstatehk Ай бұрын

This is a work of art. Been watching for a while and this channel is the best! When MendItMark meets MakeItMark, I feel a sense of serenity. Mark, get that second channel registered.

@jacktheripper6716 29 күн бұрын

mark im always amazed the amount of skill you have this shows your a true craftsman :)

@geekbot5000 29 күн бұрын

I'm American and I love your accent. You are my current favorite KZfaqr. Awesome job, I was mesmerized.

@grenvillephillips6998 29 күн бұрын

Superb video - it certainly brought back memories of casting envious eyes over Yamaha amps back in the 1970s, which seemed very classy at the time.

@billvakras8272 29 күн бұрын

I really admire the methodical way you work, your patience and your perfectionism. Your love of bringing back to life packages that no one else would repair. I don't think there are many like you. Even the videos are well taken. Thanks for what you do.

@nomada7029 Күн бұрын

This amp brings back memories of lugging that big heavy thing around with no rack case, banana adapter on the speaker terminals dangling around and all those injury-causing heat sink extrusions clipping me in the shins. Good times.

@rsc4peace971 Ай бұрын

One of the best content for any electronics, electromechanical devices troubleshooting, repairs, upgrades and RESTORATION to better than OEM, period

@LZDEN Ай бұрын

always a pleasure to watch this electronics wizard at work...very nicely done Mark..well done.

@jaycee1980 29 күн бұрын

For others watching - you have to be careful when substituting transistors in a power amplifier. It isn't always enough to make sure the replacements have the same or better specs on things like voltage and current - two important criteria Mark did not show here is Ft and Cob. You can have oscillation issues in some amplifier circuits if the outputs arent of similar speed or there is more/less Cob capacitance.

@BTW... 29 күн бұрын

Yes, seemed all too simple a sub. Was there a step missing from the work - to match the amps output gain? After all, the driver and output transistors were substituted.

@markrages 29 күн бұрын

@@BTW... Negative feedback makes the transistor gain characteristic less important -- as it is somewhat close. Gain varies more than that difference from part-to-part.

@jaycee1980 28 күн бұрын

@@BTW... No issue with gain as negative feedback deals with that, but stability can be an issue. I might have considered replacing the transistors in both sides just to make them a matched pair, though i doubt it is really neccesary.

@jaycee1980 28 күн бұрын

what Mark might have done off camera, is tested with a square wave into a load, and looked at the scope. You'd see potential instability as severe over/undershoot on the waveform, with ringing. You'll always get some peaking but as long as it's not excessive and there is little to no ringing, you are OK. The original 2SC1586 transistors had an Ft of 10MHz and Cob of 110pF, where as the MJ15023 has an Ft of 4MHz and Cob of 600pF. Unfortunately there's no fast/low capacitance power transistors made in the TO-3 package any more. I also noted that the working channel had a failed Zobel network resistor. That's usually a sign that the amplifier has been oscillating. Maybe that's what took out the channel that had no parts in it.

@hnatyshyn 14 күн бұрын

This is the most impressive one I've seen from you so far. It is really inspiring to see all the steps, including the making of custom parts. Makes me also dream of having a bigger shop and some more testing equipment and specialized tools. Looking forward for your Time Travel live workshop

@GreyRockOne 15 күн бұрын

Very intriguing! Not only impressed with your electronic skills, your design and fabrication skills also! Thank You Mark!

@normansuchorzewski1026 17 күн бұрын

Just loved watching thisv-Takes me back to my Royal Navy Days doing component repairs to communication and Radar Systems. What a beautiful trip down memory lane.

@RobertMattison-pp6uf 16 күн бұрын

This show is the best, he got every tool needed under the sun.

@FVEBlog Ай бұрын

Yesss... Mend It Mark is back. Is my favorite youtuber. 😀

@shawnhayden6674 Ай бұрын

I aquired a P2201 in 1986. Legendary. Indestructable. Great sound at home in the HiFi and kicked ass in school gymnasiums, weddings and hockey arenas. That and the P2200 are some of Yamaha's best work.

@diegorhoenisch62 Ай бұрын

Having worked with that model in the early 1980s, I can't agree with your assessment at all. Yamaha makes some excellent drums, great brass instruments, very good motorcycles, and they make amps. Not great, not good, but adequate. Yamaha's amps have rather a lot of negative feedback which gives them decent harmonic distortion specifications, but they are an unpleasant source of phase distortion. Cheers, Alan Tomlinson

@PileOfEmptyTapes 29 күн бұрын

@@diegorhoenisch62 _Phase distortion?_ What? I mean, with the undegenerated BJT input stage it's not going to be a slew rate king, though relatively high gain ought to help with that, pulling off an amplifier this powerful with an EF2 seems like a bit of a stretch, and the output stage is a tad underbiased as they usually are... but it is a PA amp after all, they're not expected to be the last word in fidelity, and this one still easily qualifies as hi-fi. If you want a model that's beyond reproach by any standard, the ones to look for would be from their mid-80s lineup, like the P2250. Later ones went back to being a bit more on the rustic side, and by the mid-'90s even the noise level had begun to suffer.

@johnburns5783 Ай бұрын

Excellent work Mark. Love your attention to detail 👍👍

@jimmy_jamesjams_a_lot4171 26 күн бұрын

Good Lord!?! What a toroidal transformer! Unlike any other transformer that I’ve ever discovered in any other piece of appliance. Nice. Balanced inputs. Your workshop is always pristine. You figure any engineer with an antique transformer curve tracer has had for himself a pretty long history of experiences in electronics. Mark, I don’t know where you got it from, but your English is the real treat of your channel! Wherever you’ve been, you really have a pleasant voice!

@D.Hozzie 29 күн бұрын

Thanks for taking the time for this Mark. Hope great things in your new shop!

@samb2936 14 күн бұрын

Very impressive work you do not everyone can do...fantastic building of the Transistor shields...cool.. nice Equipment you have either...and a great knowledge in Electronics...

@marktubeie07 Ай бұрын

2am in Australia, Mark is back, so I'll have to stay up to watch this! Must have taken ages to edit this mate, well done as usual 👍

@bigthamal 22 күн бұрын

I am really happy for you. Well equipped, well knowledged. And I am gone miss your work bench. Work safe my friend.

@MikeDS49 Ай бұрын

Is there anything you can't do? You even have a mini metal brake. Beautiful work Mark.

@redsnappa7837 Ай бұрын

Fantastic work as always, hope your cat got over the trauma of the desoldering

@wheelyman81 29 күн бұрын

Talk about going above and beyond!! I must admit to having very little clue about the technical stuff - but I look forward to every video! Thanks Mark.

@christianboddum8783 23 күн бұрын

High quality soldering - Kudos!

@iantyler4045 29 күн бұрын

Once again you have gone over and above on this rebuild. That amp will last for many more hours now. Very nicely done.

@AreTwo2 28 күн бұрын

Love your work Mark. Best wishes in your new workshop.

@VK5IR 25 күн бұрын

Amazing work Mark. Love watching you in action.

@kenp9073 Ай бұрын

Woot woot!!! New repair video. Can't wait to see what you have in store for us at your new location!! Congratulations, Mark. Thank you for sharing your knowledge with us.

@Thailandescapades 27 күн бұрын

I have absolutely no clue about electronics but why do I watch every video?? Love the channel 👌👍

@Reflectiveness 29 күн бұрын

Your videos are not only educational but also a delight to watch.

@renaldonormani6646 23 күн бұрын

I am always blown away by your attention to detail Mark. And this Vid even more. Not only the electronics! Transistor covers gave an “Out of the Park” look of professionalism. Wow)

@jcwear89 12 күн бұрын

Congratulations on the new workshop! Your channel is awesome, you are a true craftsman 😊

@DarrenBoss1984 Ай бұрын

Love watching your videos. Even though i know nothing about electronics or amps, it's still a joy to watch you fix old equipment. Goo luck moving to your new workshop.

@imnjs 15 күн бұрын

Hey Mark really enjoying your videos. Always cool to see the contrast of modern and vintage tech and how they work. Thanks for the great content!

@electronash 29 күн бұрын

I have to commend Mark again, not just for the diag and repair work, but for the camera work and editing. He doesn't just record one camera angle, but usually gets a close-up of every single step. Like adjusting the pots, he often shows a shot of the pot itself, then a shot of the multimeter. In this video, he showed BOTH pots, the inrush current, a close-up of turning the power switch on and off, plugging in the jacks, adjusting the volume, showing the o'scope, showing the distortion meter, and even making new cover plates for the transistors. I can't imagine how long it takes to make one of these vids. lol Great channel.

@robinsutcliffe-video_art 29 күн бұрын

indeed. The viewer almost has a better view than the engineer!

@vkuolema79 29 күн бұрын

So nice to see vintage lab equipment. I used to fix amplifiers and build tube amps and this gives me memories. Replacing power and driver transistors can be problematic sometimes with old amps but you made it look easy!

@vwsculler 25 күн бұрын

Love watching you work champ!

@DavidGilden 19 күн бұрын

Amazing attention to detail, well done ❤

@sarkarbroadband 23 күн бұрын

Congratulations on your new workshop. 🎉

@Ribbitmefoot 28 күн бұрын

Congrats on the new workshop.. looking forward to seeing it .

@robjw66111 29 күн бұрын

oooh new workshop!! Can't wait to see it Mark! Great job on the amp, great video as usual

@rankenfile 28 күн бұрын

Well done!! Love the details, and showing us how you got there.

@WayniKlaru14344 27 күн бұрын

Wow, I enjoyed watching every video you have, Mark. I am glad to find your channel. I wish I had those instruments you have there. I am eager to see the true sound of that amp next time for a sound test, Mark. This is a complete repair. Many thanks! Keep doing what you do.