FET Audio | Hi-End Audio & Electronics DIY Electronics & Repair

January 29, 2025

Sony TA-333ESG repair

Filed under: Uncategorized — Spencer @ 4:40 pm

Got this for $100 SGD with bad conditions and repair before by some unprofessional people. Power board use mix of power and driving transistors!  Missing big filter caps cover and metal support x 3 pcs!  PCB crack under the big cap due to movement.  This is really a old set and heavy beast. 

Repair done:

Remove all grease on pcb.

Clean and polish all the switches, then put contact oil to protect it.

Change all power and driver transistors to match pairs.

Clean and polish relay contact.

Repair crack pcb with wires, solder and solder mask.

Repair the wood board with wood wax.

Change the bias VR to 10 turn type for accurate adjustment.

Make metal support frame and cut big capacitor holder to secure it to prevent movement.

Finally all cleaning and painting of the cover to prevent rust.

Total repair many manhours!

Enjoy some pictures.

 

 

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SONOS SUB v1 Repair

Filed under: Speaker — Spencer @ 4:06 pm

Please watch the youtube for repair: https://www.youtube.com/watch?v=xdTP5gev3Ew

The failure mode is cannot power up.  Root cause is due to supply to digital board supply NG.  Changes D15, Q10, R77, R37 and Q16 (no need change as it still working). and set back to normal.

Note the cover is rusty and remove it and polish it to remove rust, then paint it with silver pen.

 

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Pioneer CLD-2750K repair

Filed under: LD Player — Spencer @ 3:47 pm

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.

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Pioneer DVL-919 repair

Filed under: LD Player — Spencer @ 3:25 pm

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!

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Audio Innovation L2 preamp repair

Filed under: Other Amplifiers,Tube — Spencer @ 3:07 pm

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.

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