Luxman R-600 restoration

Hi Fredrik, big thanks for your post!!

I am just about to start refurbishing my "new" 600 and it is my very first such project. Luckily the unit was not used frequently, overall condition is really good and all seems to be 100% original. The board was "cooked" on same place as yours, some nearby components and that resistors have burn marks but all is not so bad, all functions are 100%, even the sound is surprisingly good. Thanks to your description, all components are fairly straight to replace.

One question - I am good with basic soldering and electronics but could not really pick up how you have adjusted that biases omn R618a,b. Where should I connect my Volt-meter to set that 35mV??

Can you pleas help?

Thanks!!
 
also, which scale lamps did you use? I measure 7V, so 8V lamps are fine and available - but no idea about mA. Would they be 100 or 200mA lamps?
 
hello! nice to hear you found one in good condition.
if i remember correct i used 8V lamps rated at 300ma (not rally shure. it´s been a while.... what does your old lamps say?

the "bias" was adjusted to 35mv across what i remember was the emitter resistors farthest from the center of the board, i remember it being a "mirror immage" board. might have been R618 a and b

the unit in this thread still rocks! only a little hot from that sink, but at least i doesnt damage the board and solderings. much much better than the original design!

if i were to do this again i would probably mount a separate psu for the tuner.
 
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Thanks Fredrik! It says nothing on the bulb itself. Most of bulbs were gone when I got the unit, so I replaced them with blue-ish LEDs I had around - but the scale does not look so nice as with classic bulbs.

I'm still not sure where to place my multi-meter clips to measure the voltage.:idea:

My unit rocks too - beautiful sound and appearance, I love just to watch it running, same as I love my Marantz combo (1122DC / 2110L / 5010B) :)
 
hook DMM (set do voltage DC) to each side of the resistors at the red dots. for ex first the the one on the left, adjust the left trimmer until you get 35mv


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Huge thanks again Fredrik, that is what I was thinking of but was afraid to connect my meter to it :)

So, another question arose while sourcing some components and hoping other can benefit:
The replacement for that (single) large capacitor in power supply - you picked much larger capacity but same voltage, which is exactly opposite as other caps (capacity count and voltage can be highrer), right? If yes, why?

I am now seriously chasing one 800 or 1500

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Ah, I just got one super-rare receiver on my desk, mint and already recapped - Pioneer IN All-Wave Stereo Receiver KX-550, a black-face Pioneer from 1970.
So rare that there's near-to-zero information to be found on the web - but tracking SW 3-18Mhz (three scales) tells that it was for some unusual radio listening (GIs abroad?).
 

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that was because of the clamp.. i took one that fitted physically. and had the same or higher voltage rating...no problem to go as high as double capacity rating on that cap.

caps on the pcbs you better stick to the same capacity as stock, but go up one step i voltage. that way you make shure they will last a long long time.
 
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Bavaria :)

Pics & more history of that unit coming once I'm done, if you agree (it is your topic, not mine).
It is my very first doing this, w/o any experience in electronics, and your thread was extremely valuable.

Last missing cap just arrived (10.000uF, 80V for power supply and just built in. Tantalus are next.. are they really urgent to replace?

BTW - All resistors I replaced were still perfectly within the range, despite looking deteriorated or cooked, so it seems like unnecessary replacement.
 
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tantalums should be replaced with either film caps like MKT (polyester) or nichicon UKL low leak.
if i remember correct i used Wima MKS2
specially those tantalums in the signalpath in the tone/pre-amp section should be replaced.

post as many pics as you want.
 
So, replaced some tantalus, few caps in tuner part (hoping it did not sc** it, will see soon), fitted new fresh lamps and finally got time for some pics (I did nor forget you :) ).
 

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So, for R-600 the lamps are these; 8V 200mV maybe even 300mV.
I could not source them so places 170mV and they are almost fine, a bit too dark but still well visible, keeping original dimmed look.
I have some great white white LED that are great on Marantz but, in order to fit them into 600, I should have to remove the (tin) reflector... so i did not bother.
I just got an very fair offer for a R-800 in oerfect original condition and will probably take it :)
 
Chernobyl is under observation but it really cooking like a hell, so no way around but to fix it.
I could find 1k TO resistor but I really struggle to find that 560-570 resistors, even as combination of two.

That is super-rare KX-550 All Wave Stereo Receiver, with large scale and bunch of bands and additional lamps per-band :).
 
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so, chernobil fixed. zeners and transistors in signal path were finally replaced and that last action finally brought real improvement in sound... very, very nice now! No hiss, no hum, no noise.. wow!
I did not bypass loudspeakers caps, however, after last action the unit became good with loudspeakers, no brumm anymore when turned on :naughty:

Next project is R-800 I'll pick up soon and one Sony TA-8650 is on horizon..
 

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