Відео

Thanks for the comment. You are one of the few people who have not chastised me for ripping off the customer. Unfortunately, I chose a lone time ago to not be in the kit business. I am busy just doing my job. Thanks again for watching.

This one has the JMP50B power amp board making it a 1990. The 2100 series began in 1990 and discontinued in1993.

@ Are everyone who has this plate from 1990?

If the board is labeled JMP50C yes. Actually, like most things British it is not that simple, and can be very confusing. So let me expand on this. CD0192 Issue 1 JMP50A PCB 1989* CD0192 Issue 7 JMP50B PCB 1990 CD0109 Issue 4 JMP51A PCB 1990 CD0109 Issue 9 JMP51B PCB 1990 CD0192 Issue10JMP 50C PCB 1992 *schematic drawn in 1989 amp went into production 1990. So there you go.

I have been lobbying for adoption...... :)

Thanks for checking out the video. It is old, boring, and a horrible video but the information is 100% correct. Everyone wants to change the cathode resistor but that drops the circuit out of Class A and still does not solve the screen problem. I have seen over a dozen "experienced tech videos" that ignore the basic design rules. Thanks again for watching.

There are two sayings I live by in my shop. 1... Never question Chuck's law, and 2.... Amps ALWAYS sound the best just before they blow up. I know this one because I am constantly told by the owner that "it sounded great just before it blew up!" :)

Yep, I am sure. Same amp, same circuit board, but different power supply circuit. The Hot rods and Devilles have a different filter cap arrangement.

​@@guitarc.p.r.9675 thanks. the filter cap arrangement looks the same as my hot rod is why i asked ...

They look the same because they are. Same universal board used in all of them. So, here is the scoop. Fender was all over the place with these amps. There were multiple revisions. I have A through G plus the Service manual in my files. Basically, supposedly, according to schematics, the Blues series had the basic single filter caps, while the DeVille series had the Series cap stacks. But, there are variations of Blues Deluxes with the series caps. I also would not be surprised that wrong boards went into amps on the assembly line. Go figure. It is hard to keep straight. That is why I go by the labeling on each amp individually while referring to it. I learned in the 70's Fender was the king of manufacturing. They were the only company I ever knew to be able to get up to about 6 different models out of one complete chassis, either in head form or various speaker configured combos. Thanks again for checking out the channel. You had a legit question.

@@guitarc.p.r.9675 that explains it , thanks ..

It is a switch between drive selects for the drive channel. You can see the LED change from yellow to red when I switched it. Same board as all the other Deville/ Hot rod amps. Thanks for watching.

I hear ya. These are popular because of the bang for the buck. But, since most people really do not know what a good amp sounds like these days they like them. I have a few things that help bring them to life a little, but you can only do so much. I always enjoy the look on a customers face when I tell them the drive channel and reverb are solid state.

Creamy tone to die for. I know people who have spent a lot of money on a Z pedal to make their amp sound like that.

Read the comments here. You Epi is Metric, so you may need a different size clip.

@@guitarc.p.r.9675 Thanks. I'll buy a few sizes, I think.

The reverb tank is correct. I am betting the IC went first, and the tank was changed trying to fix it. You know, like all the forum guys say when asked about a reverb problem "Its the tank" Or they took out the IC messing with the tank.

Before I answer, I must ask... are you asking about the reverb drive, or the phase inverter?

@@guitarc.p.r.9675 Sorry, Phase Inverter.

Ok, First the question of why the 6V6 was not damaged. The high AC voltage (roughly 340v -0-340v) comes into pins 6 and 4 of the rectifier. 6V6 pins 6 has no internal connection, and pin 4 is the screen. The 5-0-5 volt rectifier heater voltages enter pins 2 and 8. On the 6V6 pin 2 is a 6.3 volt heater, and pin 8 is the cathode. The 6V6 really has no ground reference so none of the voltages can really go anywhere. I have seen these tubes swapped many times by owners by accident. Luckily, it never damages anything. Now, on to the Phase inverter question. Beginning with the Blackface amps Fender leaned more to clean, sparkly headroom. The 12AT7 replaced the earlier 12AX7 because it had less gain, and a higher current amplification resulting in more clean push for the 6V6s. Especially since it takes less signal to drive a 6V6 into clipping this was a great choice. This Phase inverter circuit is cleaner, and more balanced. A 12AX7 will work fine, but only if you are looking for a more gritty tweed type of sound. Just for fun I will add that the reverb drive circuit is designed for a 12AT7 for the same reason. Clean push is needed to drive the reverb drive transformer. So the lower gain, higher current tube is paralleled to even double the current drive but not the gain. Sorry you asked yet? :) Thanks for watching, hope this answers your question.

@@guitarc.p.r.9675 HAH! No, I'm not sorry I asked; Thanks for the explanation. Looking forward to the next video.

Next video will be up shortly. If you email me I will share an amusing similar tube swap story with you that is not suitable for public consumption. :)

Glad you found it helpful!

Sweat, pick guard gasing, and flooded basement submersion, along with years of bad storage. You should have seen the remains of the case. Thanks for checking in.

You're welcome.

Hello Homeboy! Contact me by email, the address is at the top of the page click on more. We will see if I can help you.

@ will do 👍 I’ll get in touch with you here soon and run through the problems it’s having. Glad you’re keeping the art live around here, always wanted to get into amp repair myself

I have done this many times. I have not had a single one come back with a failure. Thanks for watching.

:)

Glad you are enjoying the videos!

Thanks for watching.

Thank you. If you have followed this channel you have heard me mention I am a Mahogany wrap-around Jr. kinda guy. Came up with this solution decades ago. Have used it ever since. Thanks again for watching.

@@guitarc.p.r.9675 I just ordered a cheap knock-off Les Paul Jr. DC and have a feeling it will have the dreaded Tail piece tilt. I'll now be ready with some C snap washers.

Actually for a metric import tailpiece you may need a different size or thickness. I have actually snipped std washers to snap in and sanded to necessary thickness. Good luck it can be done.

The sheriff is near.

@@guitarc.p.r.9675 Do you think adding a music city bridge helps or just adding the E-clip to my LP Junior's OEM bridge is all I need? I hear good reviews but I want the classic LP jr. sound.

Thanks for watching. I must point out though that I truly believe the saddle was botched by the retailer's "tech", not the factory.

Congrats!

Doesn't matter, I gave the owner his choice. The Fender was the one he picked.

The washer's teeth bite into the jack surface. Same on pots, and anything else it contacts. There is absolutely no reason to solder the washer on.

Glad you enjoy them. This one was to answer a LOT of comments and questions from the first one which I mistakenly thought was self explanatory. Thanks for watching.

Glad I could be of help to you. BTW I buy Naptha by the gallon.... I use it for cleaning, wet sanding (lacquer, poly, not varnish) Raising grain on wood for sanding, and a lot of other stuff.

@@guitarc.p.r.9675 Thanks for the tips!

In case you did not catch it, check out the Gibson Barn find video. I used naptha to scrub the whole guitar down first thing! Blue Dawn, 409, and Naptha are my main cleaning agents! :)

@@guitarc.p.r.9675 Actually I did miss that video, but I'm glad you pointed out the naptha bath. Thank you!

Lock washers 101.5 for the Hardware challenged!

Glad you enjoyed it.

Most of them used to, some (Fender) still do in the US models. Ran into two more today in the shop with either stacked or no washers at all.

Even though it is not a perfect product, there are thousands of functioning ones out there. Unfortunately, all it takes is a careless supposed tech, or DIY attempt to trash one. If treated with care and respect there is not a problem. Thankfully, I have seen many more working than not. But like I said, a worn wrench, or a little man handling can create a big problem.

Unfortunately, in the repair business there is no typical cost. Every case is different and can vary widely. In this particular case though, given the time mentioned and the parts used I would say this one was probably Less than $200.

I do not care whether you believe me or not. You are free to believe what you want. This lockwasher thing is common sense. Of course that is something that is not all that common any more.

I run across a few things like that occasionally.

Not a fan of the furniture oil. I highly recommend refraining from that practice. Furniture oils can penetrate into checking and cause lifting. You do not want oil under lacquer. I always use Turtle Wax Liquid Polishing Compound to clean finishes. The same thing I used years ago to buff out re-fins and new build finishes. I follow up with Trick Guitar Polish, this is the best product I have found. You may also find this video amusing....Thanks for checking out the video. ua-cam.com/video/JTXSykia8pI/v-deo.html

The original Fender diagram from an old manual.

De-tuners.... :)

Actually, what I was telling you was, yes, the guitar was shipped that way, returned, supposedly resolved, then return shipped to the customer. Issue was still not resolved and conversation took place informing that if the guitar was sent back a second time the buyer would be responsible for shipping both ways. Then the suggestion of taking it to an Authorized Service Center was made, removing the retailer from responsibility The owner did just that and was told there were no Warranty related issues after several hours drive both ways. Then I was brought into the mix, and the problems were rectified. As to your question of why? Good question, and I hear it a lot. Facts are I expect to do a little setup work on any new guitar. Martin for example builds their guitars in Pennsylvania. You cannot perfectly set up a guitar at the factory not knowing what part of this country or other country and climate it may end up in. Another factor is not knowing what string gauge, playing style, technique, or lack there of, tuning variations, and action requirements the individual owner may have. That being said.... minor setup issues aside, much of what this owner had to deal with is unacceptable. Especially the customer service of both the retailer's service department and the authorized service center. These days I feel customer service is a rumor in many cases. As a longtime customer and friend pointed out to me in my shop recently, "Frankly, people just aren't very good at their jobs anymore." I found that to be an interesting statement. Thanks for checking out the channel.

Thanks for checking out the video. If I have a favorite 900 this would be it. This is probably what I consider to be the last "real" Marshall. The big differences here are the two gain stages in your amp are actually tubes and not ICs. From the tone stack driver on, sans reverb and a tube stage in the loop return circuit the rest of the amp is the same including the dual master volumes. I do have to mention though that there is a bridge rectifier (BR-1) and 1n4007 circuit between the preamp volume and tone stack driver tube for clipping purposes, as in the Dual reverb models. It just is not as prominent as in the 25xx-45xx models that have the Led clips in the gain channel as well. Thanks again for watching.

Thanks for checking out the channel. I don't have a definitive answer for this one, but I will try to offer my view. Many companies have a defined saddle height they shoot for to provide adequate down pressure to drive the top without excessive break angle that causes a high rate of string breakage. In Martin's case approximately 30 degrees. This height is usually somewhere around an minimum of an 1/8th of an inch. The problem here is as the instrument ages and compressions, and top deflection occurs due to string pressure, the relation between the neck angle and bridge change. This is why neck resets are sometimes necessary. As a side note I have seen many Gibson bridges that are physically too thin requiring a taller saddle than usual. Now, that being said, I believe many guitars come out of the factory with underset neck angles, resulting in the low saddle you mentioned. Some even use slotted string ramps in the bridges. I have heard a very disturbing quality control issue recently involving a particular company's neck sets and their poor solution for it during manufacturing. But I prefer not to get into that here. In the case of your Martin, lay a straight edge down the center of your fingerboard (preferably in playing position) to the bridge. It should lay on the top of the bridge, not hit below the top of the bridge between the guitar top. This is especially important if your action is high with a low saddle. Also of note, check neck relief. The older guitars did not have truss rods and the necks bow. There should only be about .005 relief in the neck. There are several Martin videos on this channel dealing with such issues. Thanks again, hope this helps a bit.

@@guitarc.p.r.9675 thanks for the great, detailed reply. My D35 is just about 30 years old, and has only been worked on by an authorized Martin luthier. He hasn’t needed to shave the saddle much yet, but that day will come, as will a neck reset at some point. I’ve done the straight edge thing a few times, it doesn’t quite clear the bra, but it’s close. Still a great playing and sounding guitar, I’d just sleep a little better knowing the saddle was a little taller. Thanks again!!

You are welcome. Sometimes there is just not a short answer. :)

It should look familiar to you. Another product of my mis-guided youth. What, you expected point to point? :)

Opinions vary on that one! :) Usually the customers that get it feel the way you do. Others not so much. Thanks for the nice comment.

@@guitarc.p.r.9675 weed out the ones that won’t listen to you

What I use are self cut nylon blanks. They are hand cut to fit what ever is needed. If you have the ability to fabricate a nut I can supply you with a blank. Email me, the contact info is in the channel description. Click on more.

A guy has to do what he has to do. Thanks for checking out the vid.

Hippie. :)

@@guitarc.p.r.9675 Pussie!

Now play nice..... For those who may see this, Ken and I go way back. This is some friendly ribbing. He also knows if I thought he was serious I would take a saws-all to his amp.

Hello Bugtustle! If I did that one it is most likely poplar. Also if it is a 2 post trem (strat std) the blocks must be used to make it solid. Thanks for checking in.

Not for this problem. However, I always move the output transformer leads as far away from the ribbon cables (input grid leads) as possible. In fact when I change transformers I actually solder the leads to the bottom of the boards and tuck them away from everything else. Just proper practice. Thanks for checking out the video.