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Re: replacing schottky diodes on a AV power supply
maybe the 340's are badComment
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Re: replacing schottky diodes on a AV power supply
Agreed.
Either the SB340's were bad ad STJ suggested or connected backwards.
-OR MAYBE-
PSU had a hickup by coincidence when the SB340's were installed and somehow voltages were off only then.
Best way to know is to repeat the experiment. Better yet, test the SB340 diodes outside first - not just with a multimeter, but rather pass 12V DC through one and feed a dummy load. Then reverse the diode and try again. In the reverse direction, the diode should be blocking any current from flowing. If it's partially shorted (i.e. shorted with high resistance), it will pass current in both directions.Comment
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Re: replacing schottky diodes on a AV power supply
Bad or faked SR340?Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: replacing schottky diodes on a AV power supply
Fake? That i could suspect. The supplier said its a chinese company made. Sighs. Looks like i need to reorder a good quality ones againComment
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Re: replacing schottky diodes on a AV power supply
Do you have any broken boards that you can find some similar diodes that you can try?Never stop learning
Basic LCD TV and Monitor troubleshooting guides.
http://www.badcaps.net/forum/showthr...956#post305956
Voltage Regulator (LDO) testing:
http://www.badcaps.net/forum/showthr...999#post300999
Inverter testing using old CFL:
http://www.badcaps.net/forum/showthr...er+testing+cfl
Tear down pictures : Hit the ">" Show Albums and stories" on the left side
http://s807.photobucket.com/user/budm/library/
TV Factory reset codes listing:
http://www.badcaps.net/forum/showthread.php?t=24809Comment
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Re: replacing schottky diodes on a AV power supply
just check any scrap psu's you have for a TO220 package schottky.Comment
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Re: replacing schottky diodes on a AV power supply
Why not test those SB340 diodes with power? IMO, no need to waste time and money looking for new diodes if you can't confirm the old one(s) is bad.
Take a 20V laptop adapter and something with a heating element that has about 10 Ohms resistance and connect it as a load on the laptop adapter through the diode. Then measure to see if the diode has proper voltage drop in the forward direction. After that, reverse the diode and test again. It should block current from going to the heating element. If you can confirm this, then your SB340 diode(s) are not bad and maybe there was another anomaly that happened at the time when you tested the PSU.Last edited by momaka; 09-01-2020, 11:41 AM.Comment
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Re: replacing schottky diodes on a AV power supply
Thanks guys for the inputs. Ive been away for quite a while now. And the parts arrived as well. Fitted in 2 pieces of sr320. Works perfectly. Wonder why the rest didnt work? HmmmmComment
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Re: replacing schottky diodes on a AV power supply
Well, if you want to get an answer for that, or at least get a clue, do the test I suggested above with the old rectifiers and the power adapter. If they test bad, then we know. And if they don't, then they weren't the issue and probably something else happened that you didn't realize was happening.Comment
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Re: replacing schottky diodes on a AV power supply
Tested the unit, everything works perfectly fine with the new original diodes.Comment
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I have wanting to do this project for quite sometime now and I finally found a switching power supply that will work on this desoldering gun station ZD-915 that the original switching power supply took a shit and just was not worth trying to fix it because this switching power is not quite big enough to handle the heater element and the vacuum pump
One note when I tested the switching power supply and the voltage control board I noticed that this desoldering gun heat up much faster than the original switching power supply which I was really surprised by to the point that I might buy... -
Dear members,
I have a linear variable power supply with unknown brand name that I used for voltage injection.
Then it failed. I discovered that its transistors (Q1 and Q2) are shorted.
In addition, I discovered that its zener diodes are defective.
I can replace the burned transistors.
But I do not know the model of the zener diodes. the model number is not marked on the zener diodes.
Therefore, I cannot replace the zener diodes.
I do not want to test the zener diodes in a test circuit to discover their model or value.
no schematics are available... -
I have been working on this concept for quite some time now with limited success but recently I found a switching power supply that is setup for the voltage that this soldering station needs to operate at however it also needs part of the secondary circuit from the original switching power because you need several voltage rails
I once tried to get a ZD-915 desoldering station to work on a 18 volt battery power supply but unfortunately things did not go well but I did find a work around but I might try this idea again but going at a little differently more about this another time... -
Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.
Upon bringing it home and plugging it up, it showed a standby light.
I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.
The screen seems to blackout and stay black, but with a flashlight I can see the display.
With my Playstation 4 connected via HDMI, and running a game I can hear sound.
Assuming... -
Hi all, I just need to know that, can i use SMPS type power supply to test and short circuit detection on a laptop motherboard?
I saw 95% of repair guys are using only Linear bench power supply. linear bench power supply is pricy, thats why i planned to get one SMPS supply.
i know that in linear power supply the noise will be very low comparing to SMPS supply....
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