This set cannot powder on and due to supply issues. Get it cheap for SGD$30 SGD and come with remove control.
Changed 3 fuses EV+5V, +12V and -12V, one mosfet on primary, and two fusible resistors on SMPS boards, then it can power up and working fine!
All metal edges painted again to prevent rusty and grease a bit inside. As usual, clean up all the dust inside the set.
Owner claim power on unstable and need to wait some time before it can power on. DAC use for this is PCM1716 and sound quite good.
The case metal edges is rusty and thus paint it with silver ink pen. Top DVD board and bottom main board is clean by ultra sonic and some magic clean solutions. After assembly, still cannot work or power on. Later found switched 5V voltage low, touching the regulator output pin is unstable voltage. Then found the cold solder joint. Thus resolder the whole power supply boards again. Stable voltage can immediately power on the set. The alps power switch also shorted and replaced by a new one. Color also missing after repair power board and later trace to a switch transistor NG. Replaced it with MMBT3904 and 1.5k resistors as no stock switch part and working well. Side B track 0 and 1 a bit jam and cause the track jump back and repeated short period. remove and grease it a bit better, may be need alignment again!
DVD is not working and will eject disc. Anyway no point to repair it as DVD player can be as cheap as $10 sgd today!
There is issue on the preamp claim by owner and cannot be used. Later find out that output has about 20-40V DC level drifting. Root cause is due to Jensen output leaking, changes to other film cap resolve the issue.
This is a faulty subwoofer and need repair, after check the pcb, it has been repair trial and see regulator transistor poorly soldered and loose joint. PCB trace on the pcb is weak and need careful repair and touch up all joints. First attempt is power amp board working but oscillation after plug in the pre and crossover boards. Later identified that the capacitors of +/-15V supply weak or not function properly. Thus replace all the E-cap on this subwooder and all working fine. Lesson learn is that Harman use cheap China capacitors and cause the problem not able to last.
Completed to re-design my old D1V3.3 or D1 clone pcb as below: Name it D1V2 + Zen I/V. Please write to me if you are interested in the PCB. No kit offer! Full assembly Boards with limited supply only.
Totally I have made 3 versions of boards for testing – V17, V28 and V30. The photos of each version is as below in sequence.
The board can use DAC – PCM63, PCM1702 and PCM1704. Note PCM170x need to use a converter board as in second picture. For digital filter, it can use SM5842, SM5843, SM5813, DF1700, PMD100, DF1704, DF1706 etc… Digital receiver is WM8804 with excellent jitter performance. More details in the reference manual below.
Compare to D1V33, it is much better in sound stage, imaging, resolution and details. It still remain the analogy sound of smoothness and best vocal DAC when PCM63 is used. When DF1704 and PCM1704 is used, the input is set to 16-24 bit digital input mode and output of DF is set to 24 bit mode. The resolution is found better than PCM63 a bit but remain the smoothness of R-2R DAC sound.
Two versions if Zen IV are tested – J/K and K/K. Here is the summary of measured results : IV resistors & capacitors and Rail comparison table_v30
Conclusion is to use the KK IV + KK Buffer – 2SK369 or 2SK363 is the optimum design choice using 20V rails. Nelson Pass original Zen IV using JK IV is having too weak output level at 30V rails. Also J74 is not available easily with reasonable cost.
Reference Manuals:
Digital filter setting table (apply to all Version boards): DIGITAL FILTER PIN CROSS REFERENCE SM5842_V30.4
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