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Switching power supply repair

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You are loosing me now. Something very basic is still wrong..

Does this unit belong to a Customer or is it yours...I specifically ask this because you are spending way too much time on this in order to make any money if it belongs to a Customer. Unless of course it was kind of working from the Customer and then all went for a pile of poo in your hands...

Tell me please :nailbiting:

Regards,
tvtech
 
You are loosing me now. Something very basic is still wrong..

Does this unit belong to a Customer or is it yours...I specifically ask this because you are spending way too much time on this in order to make any money if it belongs to a Customer. Unless of course it was kind of working from the Customer and then all went for a pile of poo in your hands...

Tell me please :nailbiting:

Regards,
tvtech

hahah... it's mine!! :D and i will be very glad if i can fix it... :) i don't know what i did wrong in the first place but after i revived it...i had that issue with the hot lm317t and then i've opened this thread here.
 
If plugging the connector in increases the LM317 input voltage perhaps a short in the connector or its wiring is causing a higher voltage to over-drive the LM317?
 
If plugging the connector in increases the LM317 input voltage perhaps a short in the connector or its wiring is causing a higher voltage to over-drive the LM317?

a capacitor short on the processing board maybe? tried to check for shorts between the processing board pins..but i couldn't understand
if something was wrong...some voltage pins had high resistance relative to GND some other had low resistance.
 
Ahhh. That explains all.

Lucky you :). I had this image in my head that you were in crap because a Customer wants his/her player...and you cannot give it back because it is worse off than when they brought it in :arghh:

At this stage then lynx, you have the time to check all that has been posted here thoroughly.

All the guys here who have contributed will keep scratching their heads and thinking...it's something basic we have missed.

All the best,
tvtech
 
Ahhh. That explains all.

Lucky you :). I had this image in my head that you were in crap because a Customer wants his/her player...and you cannot give it back because it is worse off than when they brought it in :arghh:

At this stage then lynx, you have the time to check all that has been posted here thoroughly.

All the guys here who have contributed will keep scratching their heads and thinking...it's something basic we have missed.

All the best,
tvtech

haha...

no matter how much i think of it..i can't resolve that issue...because i understand nothing!
i can't explain how the input voltage of the regulator can raise just because of the connector.

i don't see how these two can be relative... only thing i can think is if there is a short
on the processing board so the PSU raises the voltage to compensate...but the rest of
the voltages seems normal, so it can't be that.
 
haha...

no matter how much i think of it..i can't resolve that issue...because i understand nothing!

Wrong. You are another Fez in the making. You are intelligent, you listen and you try and learn. You are the kind of person I have unlimited time for.
No smartness or arguing or stupid questions..huge time for Folks like you.

We may not ultimately solve your issue with the player....gonna keep trying though.

Check out Fez here:https://www.electro-tech-online.com/blog-entries/teardown-3-1-5kw-motor-speed-controller.742/

What a nice person he is :)

Stay well, stay strong...and let ETO guide you along that crazy path that leads to Technical knowledge without all the unnecessary complications along the way.

Regards,
tvtech
 
thank you so much for your good words... :joyful: i value the help you guys offer
me on this thread because i really really want to fix this player and not dump it...

also if any other member has a word to say about the issue with the regulator it's fine!
 
If any supply is loaded past what it's specs are, then then the unregulated voltages would rise. Most switching power supplies are tested with "minimum loads" on each output.
 
Try replacing D108 and C107.
 
12vl and 32v are nest to each other in the connector. Could a pin be bent shorting them together. Measure the output of the 12 volt regulator. It should still be 12 volts.
 
Try replacing D108 and C107.

they look ok, also all the capacitors have been changed with better quality other than C129 which is behind
the heatsink of the lm317.

12vl and 32v are nest to each other in the connector. Could a pin be bent shorting them together. Measure the output of the 12 volt regulator. It should still be 12 volts.

it's always around 12v (11.45v) no matter if there's a load or not
 
Hi,

If the voltage is too high then that means something in the feedback circuit probably isnt working right.

Since they use an opto coupler for feedback, it could be that the gain has changed too much. Then again it could be anything else in the feedback circuit too.

Alternately, the load on the +15v section or the +12v section isnt what it should be. If it is too low it may not load the transformer enough.
 
Even if D108 "looks ok" it may be failing under load. I'd still try replacing it.
Did you check for a bent pin as Ronv suggested?
 
  1. The D108 must be "UPM F540" i dont know what diode that is..is it fast? also there are no bended pins anywhere..do you suggest i also change optocoupler?
is it possible to be a grounding problem? i was checking the PSU outside the dvd-r unit
so it's not grounded anywhere.
 
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OH MY GOD... it started!! while i wrote if it could possibly be a grounding issue... i thought to myself why i ask and i don't try and see
and it worked!!! but was the problem really that?....
 
I as thinking that although a bit late. I did notice that the grounds were isolated as they should be and connected at the load.
 
OH MY GOD... it started!! while i wrote if it could possibly be a grounding issue... i thought to myself why i ask and i don't try and see
and it worked!!! but was the problem really that?....

OK. Now you have to make sure it was.

Connect everything up as if it is in the "box" ALL the various wires and plugs. But the PSU must be outside.
Try and monitor the Chopper IC and the 12V rail to make sure they are not hot or unhappy.

You do not need to do this for long....just make sure all is working. Carefully now.
 
OK. Now you have to make sure it was.

Connect everything up as if it is in the "box" ALL the various wires and plugs. But the PSU must be outside.
Try and monitor the Chopper IC and the 12V rail to make sure they are not hot or unhappy.

You do not need to do this for long....just make sure all is working. Carefully now.

what if it stops working and we return to the previous state? can we find a way to revive it again?
 
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