Luxman LV 105U Phase 2 Driver Board

[@DavidOMart]

Thank you for walking through the transistor testing step by step. I know you have done some of this before and it's obvious to the more experienced. The fact that you continue to reinforce the basics is incredibly helpful for us newbs. This project is a bear, almost more bad/missing parts than good it seems. Also nice touch with the GNLE stamp on your custom made circuit boards :) Looking forward to the next installment!

[@raygianelli3612]

Thanks David! Truth be told, I'm not sure how much I'm looking forward to the next installment. Damn thing's got me like a dog that's been kicked too much. 😁

[@mymessylab]

That is a real challenge!! It’s really satisfying watching stepping trough and fix all that issues. Great job with the board.. I’m following along, thanks for the sharing.

[@raygianelli3612]

Ugh. That board is so heat damaged that I worry about long term reliability after the repair. That's why I'm trying to mitigate further heat damage as I go through it. I appreciate the encouragement. Frankly, I need it with this beast!

[@roroseppel2077]

hey Ray, it's a real challenge to get rid of all these issues ! Keep on going !

[@raygianelli3612]

I appreciate the encouragement, especially since I'm currently in the phase where I wonder why I do this to myself! 😝

[@bussypaul7326]

Hi! Really nice to see you fighting with the new challenges! Keep Going!

[@raygianelli3612]

Thanks Paul! It's proving to be more of a challenge than I initially thought. But I'll chip away at them one at a time, and hopefully new ones don't crop up during the process!

[@frankgeeraerts6243]

Hi Ray ................what a project ! There's a pe-heat function switch for the tubes... I have a 107u in stock for several years ...........I fear to look it up for restoring ......hahaha. Would like to have your spirit guiding me when I will start working on it , I am a tube man and not transistor skilled ............we'll see, maybe you will be my inspiration to get the courage to this kind of challenge. Thank you so much for being you and sharing with us. Kind regards Frank

[@raygianelli3612]

Thanks Frank. This thing is close to breaking me, but I'm not giving in yet! The preheat function is not what I thought it was; I thought it just kept the tube filaments on. It looks like it energizes the whole thing, but doesn't close the protection relay. The schematic looks like it taps the primary of the power transformer. With the power switch off and the preheat on, I get voltage at the driver board and the tubes. Explains the scorching of the PCB's!

[@poormanselectronicsbench2021]

Lots of pesky semiconductor failures on those boards, but it looks like you are sorting them out well. I feel your pain about parts orders. One vendor who's name ends with a "ey" , is really bad to deal with now too. they keep splitting my orders , about 15 to 20 different parts, into 2 separate invoices and 2 packages for shipping, even if i request in the notes field to ship "all or nothing in one package". I am going with Mouser for awhile to see how they behave, just placed a $160 order of parts mostly for a antique shortwave radio, if they do better I think I will go with them for awhile.

[@raygianelli3612]

This thing is going to push me to the edge yet. At least it forced me to learn how to have PCB's fabricated. I haven't had bad luck with either vendor. I'm just used to Mouser's interface.

[@mkach2521]

Nice work, looking forward to phase 3

[@raygianelli3612]

Thanks. Not sure I'm looking forward to it, though. Thing's been giving me fits!

[@jmqwert]

These boards looks like the Amp have been on since it was bought back in the 80thies...

[@raygianelli3612]

They might even have been preheated. 😝

[@paulb4661]

Oh Dear, I caught myself wondering for a moment, how come they used those fancy, black tinted ones in a vintage amp 🤦‍♂️

[@ec1675]

Mine left channel DC offset is about at 190mv, any suggestion on cause of this? I am guessing the 1st differential Q7103(7103-1 7103-2)? And this is one of those dual 5pins transistors, no longer available. I know this has been a while, any help would be appreciated.

[@t1d100]

👍

[@steven6692]

Hi Ray! I would love to have you recondition my old sansui receiver. It's about a1987 model sx1200. Would you be interested? Tx. Tony.

[@raygianelli3612]

Hi Tony. Unfortunately, due to personal issues I'm unable to take in any work at this time.. Thanks for your interest.

[@steven6692]

@raygianelli3612 what about in 5 or 6 months from now Ray...any hopes..or can you recommend anyone here in miami...bc I've tried but ...I just don't see it in the few I've talked to.

[@raygianelli3612]

@@steven6692 Touch base with me an a month or two. Being (somewhat) local is a plus.

[@steven6692]

@@raygianelli3612 ok Ray tx!