Repairing A Vintage Luxman L-530

[CanadianPeng]

Hey all!

I recently picked up a (from what I've been seeing) legendary Luxman L-530 Integrated amp locally for an absolute steal ($100cad)

It is in pretty rough shape but realistically could be worse, some knobs are missing/the shafts seem to be broken right off

Upon initial testing before digging too deep, I realized that the left channel didn't work whatsoever, the right sounded solid but left was DOA

Opening er up from the bottom, I immediately noticed the problem, it seems like either someone was feeling spiteful and cut the left channel transistor leads or (more likely) they were cut by a tech to troubleshoot!

All in all, not horrible for the price I paid as I was able to find replacement transistors (exact same ones) on ebay for about $30 a pair (fingers crossed they're legit). Or an even cheaper option (which I'd rather not go unless others say they're fine)

I'm just curious if anyone has any insight on replacing transistors? It looks simple enough, but from what I've read online it seems like biasing these is a massive pain.

I'm tempted to just try and re-solder these up and see what happens, but hopefully don't want to damage anything. I can't see any burst caps/damage anywhere in the unit so I'm guessing it's just these that are toast.

Any help is appreciated!

 

[Blue Shadow]

Did you test em to see if they are good? do you have a dbt to keep from damaging the unit if it has issues?

 

[CanadianPeng]

@Blue Shadow Sadly I don't have the tools on-hand to test the components individually, what would be needed?

I've built DIY boards but this is the first repair job I'm attempting, so I'm pretty new when it comes to testing

That said I'm not 100% sure what DBT stands for I do have membership at a makerspace though and it would be likely they have one as they have a bunch of miscellaneous electronics testing equipment that I just haven't experimented with

 

[Denten]

Don't even think about using those FAKE ebay outputs, not only are they fake but they are realy bad fakes!
Fujisu stoped making them many years ago.
Sanken used to make MT-200 case but recently stopped. I used Sanken 2sc3858 and 2sa1494 in my L-530, I got them from B+D Enterprises (a reputable sorurce) , I don't know if they are still available.
IMHO this is not the amp to be learning on.

 

[Blue Shadow]

Recommend learning before doing.

Dim Bulb Tester puts incandescent bulb in line with unit under test to a) limit voltage and more importantly b) limit current so if there is a short circuit in the unit it lights the bulb using up current so the unit does not suffer further damage.

I would put the amp aside and build a DBT, searching will find more info and easy to build instructions.

Then look at the DIY forum and see the sticky about "So you wanna fix stuff" by Echo Wars. It has tools list.

Another EW thread stuck in DIY is how to test Bipolar Junction Transistors and with your new diagnostic tools you will be able to test the transistors in the unit.

Expect they are shorted but just replacing them isn't usually the fix needed as other items may be damaged and cause newly installed outputs to fry just like the ones in the unit.

There is plenty of help here at ak, I know I've gotten some but most that help look to the one doing the repairs to have a few tools for testing. That voltmeter is really important.

Hope that helps getting you moving forward fixing the 530.

 

[CanadianPeng]

Don't even think about using those FAKE ebay outputs, not only are thay fake but thay are realy bad fakes!
Fujisu stoped making them many years ago.
Sanken used to make MT-200 case but recently stopped. I used Sanken 2sc3858 and 2sa1494 in my L-530, I got them from B+D Enterprises (a reputable sorurce) , I don't know if they are still available.
IMHO this is not the amp to be learning on.

View attachment 2670444

I totally agree this may not be the prime amp to be learning on, especially with how overcrowded the components are, but since I got it for super cheap I’m not overly concerned. It was from an electronics recycling place so not exactly a prime unit to begin with. Worst case scenario I either sell it to someone else willing to fix it/take it to a shop or piece off the non-broken internals to get my money back (very worst case scenario haha would rather not have to go that route)

Thanks for the recommendations on the alternate transistors though, that’s super helpful! I’ll for sure take a look and see if I can find them from a reputable source as well

 

[CanadianPeng]

Recommend learning before doing.

Dim Bulb Tester puts incandescent bulb in line with unit under test to a) limit voltage and more importantly b) limit current so if there is a short circuit in the unit it lights the bulb using up current so the unit does not suffer further damage.

I would put the amp aside and build a DBT, searching will find more info and easy to build instructions.

Then look at the DIY forum and see the sticky about "So you wanna fix stuff" by Echo Wars. It has tools list.

Another EW thread stuck in DIY is how to test Bipolar Junction Transistors and with your new diagnostic tools you will be able to test the transistors in the unit.

Expect they are shorted but just replacing them isn't usually the fix needed as other items may be damaged and cause newly installed outputs to fry just like the ones in the unit.

There is plenty of help here at ak, I know I've gotten some but most that help look to the one doing the repairs to have a few tools for testing. That voltmeter is really important.

Hope that helps getting you moving forward fixing the 530.

Thanks a ton @Blue Shadow! That’s extremely helpful!

Ill definitely be checking those out! Very much agree it’s important to learn before doing haha