Thursday, March 19, 2015

Harman Kardon Three-Thirty Nocturne

Harman Kardon Three-Thirty "Nocturne

This is something special, the early first variant of the 330(A/B/C) family. It has a beautiful full black glass like faceplate on it with accented orange lettering. The green reminded me of a early McIntosh green.

Power Supply
The original rectification used an older to-220 SB/3 common cathode diode, I prefer to use the more reliable TO-220 MUR1620 common cathode diodes, their very robust and hold up well. They used additional .01 electrolytic axial that were replaced with a more suitable 450V+ Polyester ECQ film capacitor. Those old electrolytic axial I've noticed tend not to last like their radial counterparts.  The Mains filter capacitors were replaced with a nice low profile Nichicon KG.

The power supply uses several large Elna axial capacitors, which as I noted above tended to get dodgy over this amount of time. I chose Vishay 118 AHT as a high temp very long life supply capacitor. Their very well built and work excellent in filter/smoothing applications involved with a power supply.

The amp section uses a host of 4x filter 1000uf axial capacitors mounted top/bottom chassis, where I used a Nichicon TVX, another viable option maybe some Vishay atoms. All of the low value lyrics were replaced with a nice small uniform WIMA film capacitors, the original red mylar, as cool as it looked, was replaced with a Polypropylene ECW film capacitor and Elna Silmic II's. 

Pre-Amp (hi/low level) Stage
The pre-amplifier stage used in the Nocturne is very similar to the 330A/B pre-amp stage. All the 644 BJ-Transistors were upgrade to a little more reliable modern KSC1845 package.  Elna Silmic II's were exclusively used in this application.

Tuner PCB's
Again very similar layout to the A/B 330. Lately I've switched to a low impedance, long life,  high reliability Nichicon PW for the AM/FM circuits. 90% of the lyrics here were 1uf50V in the FM/AM. The tuning cap had acquired quite a bit of dust and derby that was cleaned as well.

All in all what a cool unit to work on, the only qualm is the quality of PCB they used. Another layer of seal on the foil side would help, along with PCB printing would have been nice. It cases like this its very important to make diagrams, photos and lots of notes! After using isopropyl alcohol to clean the foil side, heat transference seem to be a little better. Most of the old soldering I just removed and relaid to make sure its solid in something this old.

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. 

Sunday, March 1, 2015

Marantz 2226 Receiver

Marantz 2226 Receiver 

This came in for a basic restoration from an AKer, was pretty damn dirty inside and the antenna was broken en route to me sadly so that harness was replaced as well.

Power Supply P800
This is a fairly typical regulated power supply found in the lower 22XX series. All the lyrics here were replaced with high temp, low impedance long life Panasonic FR/FC's. Q804 a common diode SIB0102 was replaced with an ultra fast 4005 variant. The rectifier diodes consisting of Q802 Common Cathode and Q801 Common Anode were replaced with a MUR1620 TO-220 I had on hand and a fabricated common cath.  The Main filter caps used to smooth the rectification stage were replaced with my favorite Panasonic THA's up'ed to 10Kuf which tends to increase the lower dynamic response range.  

PE01 Pre AMP
All the lower capatinence lyrics in the pass stages  were replaced with WIMA MKS2 films and FG and Silmic II's used throughout. This particular PCB uses quite a few of those orange fat originals films. Im a big proponent, like many that these are hard to beat and can make a significant perceived difference in the end product. I tend to keep them.  I like these easy access board, just remove from the front panel and your all set to go. I invert the assembly to properly clean the potentiometers. 

Phono/Control P400
This is another Phono/Combo board with the selector mechanism on board. All the lower value lytics were replaced with a low impedance high reliability Nichicon PW. Silmic's were also used. If you note any noise potentials here I would recommend replacing the 2SC1318's with a NPN 1845 BJT. Don't forget CJ01 which was replaced with a 100uf 16V Panasonic FR. 

AMP P700
This is another symmetric single PCB assembly. I replaced all the lyrics here with nice Nichicon KZ Muse polars, Silmic II's and lower value lyrics with WIMA MKS2 films. I really like these huge robust pots, so if they adjust accurately and after a light cleaning I like to keep them in this case, the shallow circle design tend to get oxidized and drift, Bourns work well in that case.  Differential pairs consisting of a pair of 2SA722 transistors at the input stage. These were replaced with 992Fbu transistor pairs. It is absolutely critical to match Hfe gain in these pairs. 

The AM/FM and tuning cap section all share a same PCB assembly on this particular unit, which makes work fast. A simple recap of this section was all that was needed using primarily Nichicon PW for the standards and Silmics/FGs for the rest of signal path capacitors. Nows a great time to gently...ever so gently and carefully clean and lubricate the spindle/shaft of the tuning capacitor assembly. 

All in all, a nice easy open unit to work on. I really like the crisp clean sound from this lil' unit, the overhaul of the amplifier section really made a difference on this 2226, it is that much cleaner and pronounced. It also has that neat extra brushed aluminum bezel on the front plate you only see on a handful of models.