Luxman LV 105U Repair Project
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- Опубліковано 6 вер 2024
- Preliminary evaluation and repair plan.
This is an interesting design containing BJT transistors, vacuum tubes and MOSFET's. It had been worked on, and parts are missing. Let the games begin!
#amplifierrepair #electronic #audio #electronicrepair #vintageaudio
Nothing like a good old-fashioned basket case to keep a person honest. I've had my share on the automotive side, and even more on the aviation side. Your skills are more than good enough to kick this one in the tail; looking forward to the next installment! Thank you for your time.
Thanks Craig! This one's gonna be a challenge for sure. I've got a lot of respect for those who can work on cars and planes. I'm not good with anything that has moving parts. Like cars. Or women. 😝
Quote by Homer Simpson: “Trying is the first step towards failure” 🤣🤣Good luck Ray, I know you will prevail! You've bailed me out before.
This is a labor of love for what would ultimately be a $250-300 amplifier when fixed! You are a patient man. Good luck with the repair, I will be following along
You're too right! Thank God love is blind so it doesn't see my credit card bill for the purchase of this amp and all the parts I'm going to have to put in it.
Thanks for the good luck wishes.
Should have gotten into knitting or building birdhouses.
I remember sticking those traces to copper boards and etching them. Mine always came out ragged looking. I have had boards made using ExpressPCB. They were double-sided. They came out amazingly professional and they were fairly inexpensive. I was shocked and proud of the end result. You have quite the project ahead of you! Good luck Ray!
Thanks Steve. You'll have to come by and see it when it's done... providing that I can get this thing working!
What did you have boards made for?
@@raygianelli3612 The standard double-sided board size was 2" x 4" with component/text silkscreen and they came in a three pack for $51. If you needed larger boards the pricing changed by the board's area.
very interesting video ray,lloking forward for the next episode 😊
Thanks Wilfredo! I'm currently in the phase where I wonder why I do this to myself. But it's really rewarding when you get something in this kind of shape working.
Ray, I've repaired several of those LV105U's. (None were that toasty). All had different issues but the IC's in the tone control were an included common fault among them. Causes static and distortion.
Also, you are Awesome! Taking the time to learn the building and design software. Something I always wanted to do but were too busy repairing and restoring other's equipment.
A whole day of frustration? I see it's worth it. I'm following with great interest. Great installment!!!
Thanks you sir! I may be reaching out to you on this as it progresses. But at this point it's going to take a lot of work to get signal from point A to Z. Static and distortion would be a step up. 😁
Copy that. Those op-amps rear their issues after you get it up and running. Thanks again Ray for the inspiration to push my skills. (In case you need them LM4562 are a good choice, no decoupling needed). @@raygianelli3612
Great stuff Ray, the possibilities are endless
Thanks Skip! I'll shoot you a text later today.
Great project Ray, its going to be a ride but good luck and enjoy it!
Thanks Peter! I expect the ride to be bumpy. 😁
A few years ago, I picked up an auction Hafler DH-220, listed as "For Parts", it had pictures listed, and most major parts seemed to be there, so, I git it at a reasonable price. After receiving it, I came to find out that the TO-3 packaged outputs, which are supposed to be N and P Channel MOSFET's, were all burned out 2N3055's. It was either purchased and harvested before I got it, or, some inexperienced repair tech thought that all amps took 2N3055's, gathered up some, and in they went. When I get to it, I will prob refit it with TO-247 or 264 packaged devices. As far as EasyEDA, I have played with it for awhile, I found, for me anyways, its best to just skip the schematic, and go straight to the PCB layout view, pick component footprints out of the library that I might need, or, make my own when needed. There's a learning curve to all of those software's, but I've found I can make a board layout and gerber fairly quickly, then, double, triple, quadruple check everything ( try to pick parts with a 3D model, and then also do a 3D view after saving, it's great for discovering interference between components before finalizing the layout) before sending it off for order, and not to be disappointed if my first attempt ends up in the trash ( recycle, of course)
Awful story about the Hafler. I don't think the seller in my case was trying to deceive anyone, but there were lies of omission.
I'm brand new to the EDA game, but I see the wisdom of your approach. The board is, after all, the end result.
@@raygianelli3612 A good practice with the EasyEDA software is to enable the "Ratlines" view ( click the "Ratlines" eyeball), which is disabled by default, so, if you are working with a schematic to board creation process, it will give you tiny blue lines to let you know what you may have missed for needed connections. The naming of, and conflicts with "NET" designations is another story, on occasion I find myself hiding errant pads under a footprint and having to go hunt to find out what I goofed up, but running a "Check DRC" will point them out until you correct them.
I have never used EasyEDA, but I have used ExpressPCB and the schematic is the critical part of the board design because you link the schematic to the board. When you place the components on the board and click on the component pads, it highlights all of the other component pads for that trace and if you are missing a component or have a trace to the wrong component leg, it tells you.
Wow, I'll have to check these things out. This sounds like really useful advice, and I thank you for posting it!
@@StevesStrayStuff I need that kind of error checking in my daily life! Thanks Steve!
This is the kind of content I love, Thanks Ray. You have a good challenge there but I'm sure you're capable to sort it out. One thing I'd like to mention and maybe you already are aware, those cooked boards can go conductive and leak current between the traces. Something to be aware of with high voltages or high impedance circuits.
Keep the great content coming Ray
Trevor! Good to hear from you!
The boards here are brown from heat, but not burned up, like you'd see if a resistor smoked. It's the carbon that causes the issues, as far as I know. Does that sound right to you?
Oh my goodness, braver man than I am ! This is gonna be a great project. This must be a decent amp when new or just a personal favourite or both ? I have a problem with these kind of amps though as in the past I've opened these 'Hybrids' only to find the Valves are there as buffers or in some instances the heaters were only wired up so they became just 'eye candy' giving that 'glow' and warmth but you don't even get that boost in the 2nd harmonic ! for goodness sake. I hate to say but most examples are cheap Chinese. I can't wait to see the circuit diagram of this old gal. I cut my PCB teeth with EasyEDA and CAD and loved it, before that it was ferric chloride all the way ! and I still use LCSC. However I found that using a browser based Cad not to my taste and of course "Real Men Don't Use Autorouters" Lol ! so I moved to Kicad (Key-cad) and never looked back as there is so much stuff that you can use to realy 'amp up' (pun intended !) your design to a Pro level coupled with the fact I loved making PCB's even in the bad old days. Great project and I will, as I'm sure many will be with you all the way Ray lol !....cheers.
Good to see you again, Andy! I'd read about Kicad, but the person who I asked about making PCB's used EasyEDA and I wanted to have someone to reach out to, so that's the reasoning behind me using it.
In this amp Luxman uses the tubes as a second differential amp.. I honestly don't know if it's beneficial or not. I just saw a challenge and a learning opportunity. Even if the only thing I learn is not to believe everything I read on eBay. 😁
Yeah it will be quite an experience. Yep EasyEda is a good place to start😁🐭 @@raygianelli3612
Grab it by the horns Ray!
It's the horns that worry me! But I'll give it my best shot.
Glad you can see it.... Because I can't.
What is it I can see that you can't?
I second KiCad and jlbpcb. I have an LV105 in storage that I need to fix the pots on so If you need any info from a working unit let me know.
Appreciate the offer. There seemed to be significant differences between the 105 and 105U, from looking at the schematics for both. I'm sure that there are similarities in areas, though, so I may take you up on it!
Pretty sure my unit is a U as well.
Is that the one Lenny had for sale? Too bad he did not have pics of the insides.
I don't know who Lenny is.
Just audio utuber @@raygianelli3612
I have a Luxman amplifier lv105u
Power transistors ( 2sk405 _ 2sj115 ) are not available in the market
There is available equivalent For installation , thanks
I'm not sure if this is a question or a statement.
@@raygianelli3612 I am asking if there is an equivalent parts for the ones I mentioned,
Thanks.
Ah, OK. No, there isn't as far as I know. I was lucky enough to find some NOS ones from a reputable seller, and they weren't cheap. But I got the last 4 he had.
can I use the mosfet ( irfp240 & irfp9240 ) < thanks @@raygianelli3612
Hope you purchased real MOSFETs, had the same amp and only got fakes
Always a risk, but I've used this vendor before and believe he's totally trustworthy. He has tons of NOS parts.
@@raygianelli3612 any chance I can get the name of the vendor? I have a LV105 here with blown output MOSFETS that I would like to get singing again.