Tuesday, March 10, 2015

Sansui TU-717 Tuner

Sansui TU-717 AM/FM Stereo Tuner

Heres a Tu-717 Tuner that came in for a recap and cleaning. The TU-717 is considered to be one of the finest looking tuners Sasui offered, matching with its partner the AU-717 Integrated Amplifier. It also packs a 4/2 gang circuit for optimal pickup and reception. 

F-2681 Power Supply
The regulated power supply is fairly compact with only 12V rails.  All the lyrics here were replaced with Panasonic FR/FC high temp long life selections. The rectifier diodes were replaced with a  more robust fast acting 1n400#

F-2679 & F-2730 Cal & Discriminator
F-2679 & F-2730 the calibration and FM discriminator assemblies were recapped using nice Nichicon PWs which is a low impedance high reliability long life capacitor, I think these are excellent for just about any stage not in the audio path or power supply. All the bi-polars here were replaced with a Nichicon VP bi-polar lytic. F-2730 is housed on top of the inside chassis vertically through a molex pin connector and shielded from the main FM/AM assembly PCB. All the pin connected boards use a very nice, sturdy gold connectors, impressive, same as F-2679.

F-2680 Selector/Control  Assembly
The best way to work on this PCB is to remove it from the front chassis panel and remove the attached LED PCB assembly from the chassis as well, this allows you to pull the F-2680 assembly down and under the dial screen and out under the chassis. This really is safest, keep that iron away from any cords and give you full access to clean the switches as well. All the lyrics here were replaced with Silmic II's and Nichicon PW's. I do want to note that the SM states C25 is a 3.3uf lytic when its really a 6.8uf 50VDC. Also note C24 is a bi-polar lytic as well.

F-2678 Tuner Assembly
F-2678 is the main PCB assembly on the chassis. Whats nice is the open chassis and wide PCB make work on this board fairly straight forward. Lower value lyrics were replaced WIMA MKS2 film capacitor for a more reliable package, and as standard with tuner assemblies I use the Nichicon PW's again and silmic II's. All the diodes/zeners were replaced as well with ultra fast 4005 and a standard 4148's. The tuning capacitor was carefully cleaned and unit brought up to spec.

I haft say this is certainly one of the best sounding and looking tuners I've worked on short of say…the Marantz 150. 

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