Philips DVD 963 on the fritz

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#41
Thomas,

change also bridge 6110 for diodes eg. byv26 or murxxx, voltage >400V. Change caps: 2116 for BG, 350V min., 2230 and 2235 for BG STD (220uf and 100uf will be ok). Caps on 5V rail 2250 (470uf is min. here), 2255 have lower influence on sound (very strange🙂). Caps on -12V and +12V can stay also if you build separated PS for output stage opamps, what gives better results. The AV board also needs many changes.
 
#43
Re: Philips 963 power supply problems

marconi said:
As it turns out, 90% of the problems come from a dead electrolytic cap.

Replace the 1000uF/16 V caps 2250 and 2210 with decent Lo-impedance 105ºC caps and mostly all is well.

If not there is little beyond the Mosfet, TY-chip and LM431 regulator that can go wrong.

Mosfets are easily replaced with more current devices from ST, like I did with STP10NK80ZFP;

the LM431 is readily available from regular sources, only the TY72011P2 is a difficult animal but here in Holland still some 20 are available throug a service-parts distributor.

If somebody needs help with this one, I can provide some assistance; but realize there are only a handful in stock there, and gone is gone.

I also have some handy tips for those who are trying to repair the psu themselves,

Just let me know,

Marcel
Click to expand...

Hi Marconi,

Suddenly my PSU stopped working. You can hear the "clicking" noise. There are no secundairy voltages present.

Any ideas?
 
#44
Hi,

Suddenly my PSU stopped working. You can hear the "clicking" noise. There are no secundairy voltages present. Any ideas?
Click to expand...

The controller is starting up, detecting a fault and shutting down again and repeating in a cycle.

Unless you want to start fault finding then, as suggested, replace the caps on the secondary side and go from there. Faulty caps won't necessarily measure badly on a DVM. I have also experienced the controller ICs on these board failing (the protection for them could be better). Do you have / want the schematic ?

Cheers,

Jon
 
#45
Also check the diodes. I have seen one short circuited more than once. Be sure to replace with appropriate very fast diodes otherwise the switching losses will burn them up.
But like JonHarrison sez, start with the electrolytics. Use low impedance types with 105 degree C rating.
If that brings no success, replace the Mosfet.
Keep us posted, good luck.
 
#46
Don't think it will 'tick' if the mosfet has already failed. Good point about the diodes, there are two axial diodes mounted off the board. Is the pcb scorched under them ? If you're replacing the diodes consider fast/soft recovery types or schottky. Caps - Panasonic FM or Rubycon ZL(H) work well.
 
#47
JonHarrison said:
Hi,



The controller is starting up, detecting a fault and shutting down again and repeating in a cycle.

Unless you want to start fault finding then, as suggested, replace the caps on the secondary side and go from there. Faulty caps won't necessarily measure badly on a DVM. I have also experienced the controller ICs on these board failing (the protection for them could be better). Do you have / want the schematic ?

Cheers,

Jon
Click to expand...


marconi said:
Also check the diodes. I have seen one short circuited more than once. Be sure to replace with appropriate very fast diodes otherwise the switching losses will burn them up.
But like JonHarrison sez, start with the electrolytics. Use low impedance types with 105 degree C rating.
If that brings no success, replace the Mosfet.
Keep us posted, good luck.
Click to expand...

Hi Jon and others,

I used a blowheater to warm up the caps and the unit started.

I replaced 2210, 2230 and 2250 and it did the trick.

Thanks for the posts guys,
Roel
 
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