Technics SU-V98 Repair

[SpecialK]

I'm just in the middle of repairing a Technics Su-V98 integrated amp.  Low output on the right channel.

https://www.manualslib.com/manual/387815/Technics-Su-V98.html

I've traced the issue to Q202 (see page 9).  Removing this TO-92 N-channel Mosfet restores normal operation.  I assume that if I had a working remote, then pressing the mute button would cause only the left channel to mute with Q202 missing.

Can anyone recommend a substitution for a 2SK301? 

[coromonadalix]

for an example if you do a cross check like this

https://www.digikey.com/catalog/en/partgroup/n-channel-mosfet-metal-oxide/16095

youll have some compatible parts,    it should be okay to use them as a mute function,  you have at least 3 or 4 models in to 92 casing


one popular transistors was dtc114

theses mosfets  too
J108/ 109/ 110


The  "RDS" spec would be the first thing to be considered, any low power n chanel mosfet

2sk715v or 2sk715u, 2sk223  seems to fit the bill

[SpecialK]

Thanks a bunch.  I might add something to my next Digikey order.  I think it's actually a JFET and not a MOSFET.

More perplexing is the remote.  The seller sent one, but said it wan't working.  Seems to emit IR just fine.  It doesn't match the picture in the manual.

However, I'm at a loss to see the IR sensor.  Do they ever imbed them in the Vacuum Florescent Display? 

[coromonadalix]

nope never, its kinda a metallic smal can with 3 legs  or somekind of a dark led, they are always on the front panel side, sometimes on the main pcb or its an separated pcb with the metalized can or a infrared diode

[coromonadalix]

Buuuuut    i'm not sure if this tuner / amp need to be connected with other sound system components

You have some remote plugs on the rear,   see page 3 and 4

Some of theses systems where not working if they where not complete,   tunner, amp, preamp  ...

[SpecialK]

nope never, its kinda a metallic smal can with 3 legs  or somekind of a dark led, they are always on the front panel side, sometimes on the pcb or its an separated pcb with the metalized can

My latest theory is that there isn't an IR sensor on the integrated amp.  Apparently, the integrated amp was usually (or always?) sold as an ensemble with a tuner tape deck, CD player, and turntable.  The tuner clearly has a sensor and then there's a cable between units.

The good news, is that I can just leave the FET out as it will never be muted.

I see you already posess such knowledge.

[coromonadalix]

Had my fair share or audio video equipment repairs   in the past   loll  but im getting old loll