Luxman SQ77T - II

[Sam08861]

If you know your way around, I Would definitely replace the electrolytic capacitors on this one.

Have no idea why it was suggested not to.

Edit.. See you did that.

 

[kelvin16]

Yeah the big round ones are 2SB421 germanium, was hoping to do a silicon replacement and did find a diagram somewhere on the web - below- that showed BC640 replacing this and BC639 replacing the NPN (2SC826) then one resistor changed value from 10 to 22ohms to sort the bias out (?)This substitution did not work out however and I decided to go back to the original transistors at least until the recap was done. The other ones in the preamp and main amp were 2SC369 which I have switched out for low noise 2SC2240.

I did find some ST Micro 2N3773 and may try those out and see if things improve at all with the noise.

cannot found SQ-77T full schmantic , unfortunately

 

[AvSat44]

Hey kelvin16,
If you want to tell me your email address, I'll send you the whole user manual which includes the schematic.
Cheers.

 

[Dswankey]

^ Generous offer @AvSat44 however maybe private message him with your offer. Posting an email address on an open forum is not a good idea

 

[afroaudio]

Reporting back, my SQ77T/II has new germanium ACY17 installed replacing 2SB421 and is singing as it should and sounding great! This little amp does have a certain magic to it.

20200421_110227 by Jonathan Chiles, on Flickr

 

[Henry2610]

Reporting back, my SQ77T/II has new germanium ACY17 installed replacing 2SB421 and is singing as it should and sounding great! This little amp does have a certain magic to it.

20200421_110227 by Jonathan Chiles, on Flickr

Hi Jonathan,
I’m a new owner Luxman SQ77T/II, which having hum, so I wanna upgrade the transistor.
Just wondering the ACY17 perfectly worked on this Luxman or not?
Thank in advance
Henry

 

[artess97]

Currently undergoing a germanium to silicon conversion on this amp using a low gain BD140 in place of the 2SB421.

If anyone has the schematic, could you please get it touch with me. It would help a great deal, especially when it comes to biasing the BD140.

Thanks, Rob

 

[afroaudio]

Hi Jonathan,
I’m a new owner Luxman SQ77T/II, which having hum, so I wanna upgrade the transistor.
Just wondering the ACY17 perfectly worked on this Luxman or not?
Thank in advance
Henry

If you problem is hum you are more likely having issues with ageing electrolytic capacitors. I would recapat least the power supply and then test again. The boards come out quite easily so probably worth recapping entirely. Vishay 021ASM axial caps are suitable replacements for the original blue Nichicons.

 

[captainjim]

I have one of these! It belonged to my Dad, and I'm looking to sell it as I'm about to move house. I'm in Melbourne if anyone's interested

There's also a B&O record player. Both in need of some T&C.

 

[ABeer]

Hey kelvin16,
If you want to tell me your email address, I'll send you the whole user manual which includes the schematic.
Cheers.

Hi AvSat44 I have sent you a direct message because I need a manual and schematic…my recently acquired 77Tii has decided to “flip out” and check itself into the repair spa for some love.
Cheers AB

 

[ABeer]

Hi Jonathan,
I’m a new owner Luxman SQ77T/II, which having hum, so I wanna upgrade the transistor.
Just wondering the ACY17 perfectly worked on this Luxman or not?
Thank in advance
Henry

Hi all, same possible situation. Did the ACY17 do the trick. Given order and delivery lead times on those are 20-25 business days, if I’m going to do that I want to get the process started. Noob needs to know how many too!
Thanks AB