My Wanptek KPS305D bench power supply died after about 6 months. As luck would have it, replacing one surface mount chip brought it back to life. TNY277GN from Mouser - www.mouser.com/...
I know this is a couple of years old now but it was probably the Battery which fried the chip! Cheaper supplies (especially chinese ones!) do not have diodes on the output so the battery can backfeed into the system and damage it. Add a diode to the output + line and you will be fine in the future. Note: when adding diodes in series, there will be a voltage drop (about 0.6v) so your actual voltage at the battery will be lower - measure actual voltage at the battery with a multimeter and adjust the output of the power supply to compensate . I add these comments only to help others who have had this problem and so they know what can actually cause and prevent it. Thank you for your video!
Maybe but I'm not sure I buy that explanation. It seems to me that connecting a 4v battery to the power supply would be much less stressful then setting the supply voltage high (15v) and then setting it back down low. It either case the internal capacitor temporarily stores a voltage higher than the commanded voltage while the internal resistors work to dump the capacitor. I assume the power supply is designed to handle that scenario, but as you said, it is a cheap Chinese unit.
Thanks for posting this. I bought one of these, and after initial testing to be sure it was OK, it has been sitting on the shelf for the last 10 months and I finally pulled it down for a project only to have it die about five minutes into the project. Totally black display. Fuse OK. I ordered a few of the parts and hopefully it will get it back up and running. I didn't think I expected much out of this for the price, but I surprisingly got less than even my meager expectations. LoL
Good work. I just received the same unit KPS305D. I found the internal mains earth was connected to the bottom case indirectly through the earth aluminium internal heat sink. The paint on the base stops it earthing the case. I scraped the paint off one of the screw holes and found that that gave a good earth.
TNY chips are off-line chips used in flyback supplies under 20W (mobile chargers mainly). most probably it's used for the internal stand-by supply for the main switching chip (probably a TL494)
This worked out great for me. Thanks a lot for your video. The new IC moved out of place by the slightest touch, so I used some putty to keep it from moving.
That chip is rated for use in up to 18W power supplies in open frame designs and there are 2 discrete primary switching transistors on the left of the board, so I think if that chip is just running the aux power supply for the front panel and control logic. That would make sense as the front panel has to work when the main output is off, but I don't know what has to happen for such a component to blow, you wouldn't think it would be under much stress. I normally don't mind Power Integrations chips for simple use cases such as aux supplies. The TOP221-227 family chips are quite common. I've seen them used for aux supplies in ATX PSUs before. The common theme for these Wanktek KPS series power supplies seems to be that they're pieces of shit anyway, dead within 6 months if not dead on arrival.
Wow. I just buy 10 of those at AliExpress for 4€ (long) delivery included. I have concluded the same thing and then I was courios if someone has had the same issue with this PS. and i found this OLD video form the "time tunnel". I will look arround to sea what part of the PS has a bad design for this part. Thank you for posting this.😂
I'm in the same boat, can't get voltage past the TNY277GN. However replacing it didn't solve my issue. Just to be sure, I replaced it with another one and still nothing.
Same power supply. Output power and screen display go off after few minutes working... Then I need waiting tny277gn cool from 130°C (case) to less than 75°C to restart and get the screen display and output power back. Cooling requires unplugging. If not, tny277gn stays at 130°C despite no output power and screen display off. Dont know if Tny is the faulty component or if its overheating is due to something else...
I had the 4 digit model (KPS3010DF where F denote 4 digit display for voltage / amperage). This is good bench variable PSU for its price (I am not expecting precision lab psu for the amount I paid). I noticed your voltage limiting (CV) LED on the display is not lighting up? The LED on mine burn out after a few mths and I end up replacing it. The coarse voltage potentiometer also went bad a few days ago and I had to re-place it as well. Now everythings works perfect.
I have an EventeK made by Wanptek, I can't tell if it's a new revision, but the main board is marked Wanptek, and a V1/M-1709. It is a different design, but uses this same Tinyswitch for what I believe is a boot strap supply. Mine died on initial powerup. I'm looking at your rear 115/230 VAC input switch. At the end of your video, this looks like it is slid away from the camera, and I assume this is the 115 position. Mine is in the closed position, and shorting the red and black wire together, and indicating 115. I'm thinking they assembled this wrong in the factory. I'm trying to draw out the schematic, and it looks like part of the bridge rectifier is shorted out when this is closed, so that I would think would be the 230 switch position. If you look at the rear of your supply, is the 115 position to the left as this is how the switch looks on your video? And it looks like the red and black wire are not shorted. Thanks
Anyone have a P/N for Q1, Q2 which are shown to the left under the fan? Mine are shorted but have no stampings on them. Can't find a schematic for this board anywhere.
@SPY ANIME I looked in my notes and found P/N 2SK3569 for the two unmarked transistors if you have an issue with them. Never did find a schematic but replacing these fixed my power supply.
I am looking for recommendations for a decent PS to run a four lane HO slot car track and a two lane 1/32-1/24 track that won't prematurely go "poof". Both analog tracks with stock to lightly modded cars only. 20V/10A or a 30V/15 PS would be nice. Many I see on Amazon or eBay have "iffy" reviews.
Hi. That noise that comes from the PSU is normal? I mean, it was present even when the PSU was new, no repair at all? I got mine repaired and i hear that noise but cant remember if it was present before broke down. Thanks for the video.
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I know this is a couple of years old now but it was probably the Battery which fried the chip!
Cheaper supplies (especially chinese ones!) do not have diodes on the output so the battery can backfeed into the system and damage it.
Add a diode to the output + line and you will be fine in the future.
Note: when adding diodes in series, there will be a voltage drop (about 0.6v) so your actual voltage at the battery will be lower - measure actual voltage at the battery with a multimeter and adjust the output of the power supply to compensate .
I add these comments only to help others who have had this problem and so they know what can actually cause and prevent it.
Thank you for your video!
Maybe but I'm not sure I buy that explanation. It seems to me that connecting a 4v battery to the power supply would be much less stressful then setting the supply voltage high (15v) and then setting it back down low. It either case the internal capacitor temporarily stores a voltage higher than the commanded voltage while the internal resistors work to dump the capacitor. I assume the power supply is designed to handle that scenario, but as you said, it is a cheap Chinese unit.
Thanks for posting this. I bought one of these, and after initial testing to be sure it was OK, it has been sitting on the shelf for the last 10 months and I finally pulled it down for a project only to have it die about five minutes into the project. Totally black display. Fuse OK. I ordered a few of the parts and hopefully it will get it back up and running. I didn't think I expected much out of this for the price, but I surprisingly got less than even my meager expectations. LoL
Good work.
I just received the same unit KPS305D.
I found the internal mains earth was connected to the bottom case indirectly through the earth aluminium internal heat sink.
The paint on the base stops it earthing the case.
I scraped the paint off one of the screw holes and found that that gave a good earth.
The "triac" you are referring to, is not a triac, but a full wave bridge rectifier. It converts the AC to DC.
TNY chips are off-line chips used in flyback supplies under 20W (mobile chargers mainly).
most probably it's used for the internal stand-by supply for the main switching chip (probably a TL494)
This worked out great for me. Thanks a lot for your video. The new IC moved out of place by the slightest touch, so I used some putty to keep it from moving.
i wish you could make a video on how to diagnose with multimeter
Good diagnosis and repair.
That chip is rated for use in up to 18W power supplies in open frame designs and there are 2 discrete primary switching transistors on the left of the board, so I think if that chip is just running the aux power supply for the front panel and control logic. That would make sense as the front panel has to work when the main output is off, but I don't know what has to happen for such a component to blow, you wouldn't think it would be under much stress.
I normally don't mind Power Integrations chips for simple use cases such as aux supplies. The TOP221-227 family chips are quite common. I've seen them used for aux supplies in ATX PSUs before.
The common theme for these Wanktek KPS series power supplies seems to be that they're pieces of shit anyway, dead within 6 months if not dead on arrival.
Wow. I just buy 10 of those at AliExpress for 4€ (long) delivery included. I have concluded the same thing and then I was courios if someone has had the same issue with this PS. and i found this OLD video form the "time tunnel". I will look arround to sea what part of the PS has a bad design for this part. Thank you for posting this.😂
My KPS305D fail today, the TNY277GN blow up.
I bought 3 IC's, I think this is a commun problem.
Cheers.
I'm in the same boat, can't get voltage past the TNY277GN. However replacing it didn't solve my issue. Just to be sure, I replaced it with another one and still nothing.
hi i have a big problem with two K3569 i replace this components but next 1 minute of utilization K3569 go broken another time!
Same power supply. Output power and screen display go off after few minutes working... Then I need waiting tny277gn cool from 130°C (case) to less than 75°C to restart and get the screen display and output power back. Cooling requires unplugging. If not, tny277gn stays at 130°C despite no output power and screen display off. Dont know if Tny is the faulty component or if its overheating is due to something else...
same issue. now. after years of use!! any other finding?
HOLY MOLY! Does it get THAT hot 🔥?
No wonder it's unstable after a few minutes...
My unit blew up my brand new circuit before "self destructing"!
congratulations, thanks for sharing
Thank you very much
debe ser el conmutador principal
I had the 4 digit model (KPS3010DF where F denote 4 digit display for voltage / amperage). This is good bench variable PSU for its price (I am not expecting precision lab psu for the amount I paid). I noticed your voltage limiting (CV) LED on the display is not lighting up? The LED on mine burn out after a few mths and I end up replacing it. The coarse voltage potentiometer also went bad a few days ago and I had to re-place it as well. Now everythings works perfect.
KC Goh - Yes, the voltage led was bad. The course voltage pot actually failed on mine a few days ago. Replaced the pot and the led and all seems well.
I have an EventeK made by Wanptek, I can't tell if it's a new revision, but the main board is marked Wanptek, and a V1/M-1709. It is a different design, but uses this same Tinyswitch for what I believe is a boot strap supply. Mine died on initial powerup. I'm looking at your rear 115/230 VAC input switch. At the end of your video, this looks like it is slid away from the camera, and I assume this is the 115 position. Mine is in the closed position, and shorting the red and black wire together, and indicating 115. I'm thinking they assembled this wrong in the factory. I'm trying to draw out the schematic, and it looks like part of the bridge rectifier is shorted out when this is closed, so that I would think would be the 230 switch position.
If you look at the rear of your supply, is the 115 position to the left as this is how the switch looks on your video? And it looks like the red and black wire are not shorted.
Thanks
I have to ask you . please see the resistor values adjustment on the front panel . I really need to know what resistor values . thank you
Great ,, I saved A psu from e-waste thanks to this :)
Anyone have a P/N for Q1, Q2 which are shown to the left under the fan? Mine are shorted but have no stampings on them. Can't find a schematic for this board anywhere.
@SPY ANIME I looked in my notes and found P/N 2SK3569 for the two unmarked transistors if you have an issue with them. Never did find a schematic but replacing these fixed my power supply.
I am looking for recommendations for a decent PS to run a four lane HO slot car track and a two lane 1/32-1/24 track that won't prematurely go "poof". Both analog tracks with stock to lightly modded cars only.
20V/10A or a 30V/15 PS would be nice. Many I see on Amazon or eBay have "iffy" reviews.
Hello there.My model ( KPS3010D )The same piece Burned.Turkey this track problem.Which parts are compatible?help please.urgent...Necessary piece.
Hi. That noise that comes from the PSU is normal? I mean, it was present even when the PSU was new, no repair at all? I got mine repaired and i hear that noise but cant remember if it was present before broke down. Thanks for the video.
Heh, I dunno if it is just me, but I always seem to see those TNYxxx chips blown up.
That's a major flaw. It cost me a irreplaceable circuit...
My power supply is making some sort of clicking noise and the display won't turn on was it the same for you?