How to Troubleshoot MojoTone Kit Fender Deluxe Reverb Tube Guitar amp + New D-lab Dummy Load Intro

Yes, a cool repair. plus a new D-lab electronics gadget offering. I have been asked many times over the last few years to produce a new versatile test dummy load system. So, here it is, The DummyHead! Works great, compact, great addition to your test bench. I have limited supplies to build, so get with me soon if you want one. TD

[@hddbugg]

You have a talent for troubleshooting and teaching

[@zbaby82]

I love it when you repair things Terry.

[@f.k.burnham8491]

Terry- Per datasheets on the resistors when I built my dummy load: The 50 W rating is only valid if the resistor is properly heatsinked. Mine are in 1 gallon cans full of oil, similar to the old Heath "Cantenna"

[@rillloudmother]

that's good, in case you leave it on during the rapture.

[@kbkman7742]

At least they had a sense of humour with the red inspection marks

[@HorsetoothMtn]

I think that was the builder putting on loctite after the fasteners were tightened (fail)

[@krauz111]

I am about to build one of those, good to know all these tips

[@guydouglas6094]

I enjoyed this video always thorough and a keen eye. Look forward to part 2 video and the outcome.

[@Strumbum01]

Thank you for a great video as always!

[@danielsaturnino5715]

Thanks Terry

[@edwardhannigan6324]

Nice walk thru Terry. Shows you, the builder has to take special care and check and double check not only the circuit but also their connections..Look forward to part 2..ED..uk..😀

[@electrolytics]

Real good camera work. Another great video. That Dummy Load Box looks smart.

Happy Labor Day Weekend! Blessings from the left coast. Hollywood California!

[@DiegoCastro-kn9tl]

Yesterday i wire a jack wrong, just because im following the switchcraft scheme but, this jacks tip and switch is inverted. lol

[@nizzamp]

This is one of the coolest vids I have ever seen

[@dreamsofeden]

Working in a Silvertone 1300 right now…. A beautifully simple widow making piece of history

[@RaptorRotorHead]

Look how awesome and clean that chassis is

[@dennisflock3958]

Great troubleshooting!

[@russellesimonetta3835]

Very good as usual! Many bigbthings andvlittle things can go wtong eith kit builds. #1 missed under board jumpers, #2 sloppy wiring #3 BAD GROUNDS!! Tag strips are o.k., but solder tabs and puddles are best. The copper plate works great and looks authentic but like the fibre boards can cause problems ten or twenty years down the line. But you are the man Terry.

[@bdagle]

Hi Terry, I had one of those amp kits come across the bench a while ago. Basically, the owner did a nice job building the kit, but he did have several wiring errors. Your right, that when you are troubleshooting one of these kits it's just like you were building it yourself. LOL! Brendan

[@kbkman7742]

From what I have seen, people rush into them and play connect the dots without learning how the circuits work first

[@hestheMaster]

Love your dummy load box. Three position switch is a great inclusion. What kind of heatsinks are in that small box? Hmm. Kit built amps are troublesome when something goes awry. Too many newbies think it is easy. It is not. Takes both knowledge AND a little self discipline. Practice soldering and building smaller projects first was my key to success here. Good thing Terry is expert in hunting down someone else's mistakes. That's why I watch.

[@dreamsofeden]

Hey Terry! Always a treat to see new a video from you… how can I get a dummy head boxy thingy? LOVE it! (Just got to fix my oscilloscope…)

[@pd9458]

Hi Terry, I'm interested in a Dummy Head. Can you send to the UK?

[@sparks3019]

Love this kind of video. Would be very interested to see the dummy load construction video. I would even purchase instructions and a parts list. Any chance of that? Thanks.

[@d-labelectronics]

Yes, A full construction video is in the works

[@kimmassey6596]

I want one.

[@acoustic61]

I always use a 6 ohm resistor for a dummy load. I don't believe impedance is critical for brief testing as long as there is some load.

[@anks888]

The brass plate is a common reason for problems itself

[@audiotechlabs4650]

Glad to see another tube amp video Terry! I’m a little surprised you don’t use a shielded cable to the input to the channels. Also would say 20-22 ga. solid wire be sufficient for the heater wiring? The rectifier tube would need the larger 18 ga. for the higher current. Does Mojo Tone offer a faceplate with the Deluxe Reverb Amp logo? The ones I saw on their website has no such logo? Where would one find a said faceplate with the logo. Still love the channel and look forward to another one of your expert amp repair/build!s! Love from the great Rocky Mountains. Thanxz

[@d-labelectronics]

Yes Sir, I have added RG174 to the input jacks and properly wired them. This ones a work in progress. Reverb & Tremolo are inop. Part 2 will go deeper. Yes Filament wiring will also be covered.

[@kookoogearkook]

Where’s part 2 ? Would love to see

[@y_x2]

I guess that if you found one wrong resistor you must have another one with the value reverse somewhere else...

[@brich2929]

Right!

[@waynethompson8416]

That black and white twisted wire looks a lot like 12AWG house wiring...aka solid wire. I just hope that the owner of the rig has enough common sense to approve you doing what is needed to be done on this rig. Especially to add the RG174 coax to it. Concerning the non-working input jacks, how about a before and after schematic of the wiring of it?

[@hddbugg]

That dummy (not you) looks great

[@Skman22]

Interested in the dummy load unit! Ship to Australia?

[@ronjinks8932]

Fan or not ;Terry, 18gauge solid wire was (is) the de facto standard from the 50's through the 60's for high current heater loads.

[@Blindfacetweed]

Yeah, but the guy used stranded wire. Look closely at the yellow wire going to the input jacks resistor.

[@MrSteveCasper]

Where did the owner get the fender faceplate? I'm about to order this same kit but it has a blank/no name faceplate. How much for the dummy load box I may be interested.

[@mojo6706]

Hey Terry, at about 2:50 it looks like the red wire from the power transformer going to the rectifier tube is just hooked on.

[@d-labelectronics]

Will take a look, Thanks for the info

[@jasnic2131]

I saw that too

[@hestheMaster]

Looks that way to me too. Very little solder on the pin contact only on the wire. Good catch!

[@stevelark9840]

Good eye, I saw that too

[@guydouglas6094]

I was gunna say that ............. no I wasn't

[@danielcarrete2972]

I built a similar kit as this one (Tweed 5E3) and use it as my main amp. All of a sudden, I have an oscillating kind of tremolo sound… it will even cut off and will not be able to get a sound out of it. I used to hit it like an old tv and it would take care of it (I know, not the best troubleshooting) but not anymore. Do have any idea what it could be? Any help is appreciated. Thanks!

[@matthewf1979]

That circuit is a tough one for newer builders. The wiring is confusing and lead dress has to immaculate for the reverb circuit. If this was a Mojotone kit, it definitely didn’t come with any of that wire. All of the wire included in their kits is solid core cloth covered 22ga and 18ga for the heaters. After seeing the Hammond transformers, and the Fender labeled faceplate, I don’t think it is a Mojotone kit. Even their small parts kits include the vintage style wire. I would gut it and rewire the entire amp. I’d bet that the reverb is noisy as all get out too.

[@gpdllcfun1]

Hey D-Lad do u have a schematic for a crate vc6212 60 watts

[@garyslivewire1358]

Hey Terry. Sign me up for a dummy head

[@neccron9956]

Where did the original 470 ohm resister go. If the kit had a 470 & a 47k, then is there a 470 in where the 47k should be?

[@steveh1273]

For the RG174 shielded cable, do you ground the shield and if so, at what end? So, how do I get me a D-Lab dummy load?

[@fiddlix]

You do ground it only on one end..generally at the controls and or input jacks.

[@fiddlix]

If you want one of his dummy loads go to his website.

[@rickymize8673]

Hey how much for the dummy box

[@JasonTHutchinson]

I had plans to build one of these switchable dummy loads, but couldn't quite figure out the switching. Those resistors will not work to spec without the proper heatsink.

[@d-labelectronics]

This device is for testing, not baking. Yes, I realize they need a heatsink for full power. That is not the intension of this device.

[@JasonTHutchinson]

@@d-labelectronics The box you made is basically the exact thing I was trying to build. The amp I'm working on has a 16 ohm speaker. I believe it is possible to get 4, 8, and 16 ohm configurations using only 2 resistors, although I'm not sure how to switch between them. I was able to figure out how switch between 4 ohms and 8 ohms on my dummy load, but 16 ohms eludes me. I'm currently using 2 8 ohm, 100 watt resistors. I should actually replace the ones I have because they are the wrong type. Looking forward to hearing what this amp sounds like.

[@d-labelectronics]

Hi Jason, Thanks for the reply. Yes, the switching is a bit tricky. As the project grows, I will put out another video showing the construction details.

[@basstracker2100]

do you sell a parts kit or just put together dummy head? and how do I get send you the money?? Thank you

[@timmooney7528]

It could be worse, and the owner could've had a buddy cobble it trying to make it run.

[@dochort21]

I’m confused. The schematic shown shows the tubes as 6L6GC. Would that make this a Pro Reverb?

[@d-labelectronics]

Inverter stage is the same on the AB763

[@cliffyoung5712]

I screwed mine to an old PC CPU heatsink.