When Turns on Its shows approx 4volt and goes to zero. No Current and No voltage at output. Uses TNY277GN My question if any one knows the voltage between drain and source pins, Currently it is like going into loop from 0 to 330Volts. Thanks
-
-
Re: KPS305D Bench Power Supply
Look for a diode across the output terminals or on a board that might be shorted
This would be the first thing that I would look at
The second thing I would do is replace the TNY277GN these type of devices have a history of going bad for apparent reason
Or the capacitors around the TNY277GN might be the first thing that I would try before replacing the TNY277GN ic chipLast edited by sam_sam_sam; 10-28-2022, 01:02 PM. -
Re: KPS305D Bench Power Supply
Thanks SAM
I checked diodes and all seems ok. I also have doubt on TNY277 but before replacing want to be 100% sure.Comment
-
Re: KPS305D Bench Power Supply
If the source pin connects directly to hot ground (- of main bridge rectifier) then there is no way that the TNY277GN is dropping the 300v to 0, it's top would have blown off the top. Check the voltage across the man filter capacitors, is it also dropping? if it is staying at 300v, check the components between the main filter and the drain of ic501Last edited by R_J; 10-28-2022, 03:21 PM.Comment
-
Re: KPS305D Bench Power Supply
R_J I will check and will post results tomorrow. I did the checking last time and AC circuit was ok (at least seems ok)Comment
-
Re: KPS305D Bench Power Supply
i presume this unit doesnt have a stupid PFC circuit?Comment
-
Re: KPS305D Bench Power Supply
Hi Guys, trouble shooting is going on in slow motion. I found shortage on smd capacitor c44 and pin 4 and 5 of LM358, Remove the capacitor and checked it but it was not short. Removed LM358 and it seems ok outside the board but still there is short between pad 4 and 5. Is it normal ? please adviceAttached FilesComment
-
-
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... -
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... -
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.... -
Hie I have a Lenovo laptop
Lenovo Ideapad 100-14IBY AIVP1-AIVP2 LA-C771P rev 1.0
it's working only on the bench power supply when I put the battery it doesn't power on. when I also use the original charger it doesn't power. the batter Is fully charged, I used another laptop to charge the battery. but when I use a bench power supply it works perfectly
below are my readings
with the original charger only
JBATT1
PIN1 0.22V
PIN2 0.22V
PIN3 0.45V
PIN4 0.45V
PIN5 O.43V
PIN6 0V
PIN7 GND
PIN8... -
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...
Comment