UMEC AD-UP220-AE Power Supply schematic needed

[Keshenatech1]

I'm looking for a schematic for a UMEC AD-UP200-AE power supply used to power a Tatung 32" monitor. These are end of life and not available anywhere so I'm trying to fix a couple bad ones. Thanks

[Keshenatech1]

Re: UMEC AD-UP220-AE Power Supply schematic needed

Here are a few pictures of it. I uploaded them on the first message but they didn't show up.

[SMDFlea]

Re: UMEC AD-UP220-AE Power Supply schematic needed

I don`t think the schematic is available. I did find a bit of info regarding Q10 http://forums.delphiforums.com/slott...ssages/14714/1 (view googles cached page)

Also you can get a repair kit,its worth checking all parts that are listed to see if anything has gone tits-up

http://www.ohmsupplies.co.uk/epages/...roducts/KIT198

[Keshenatech1]

UMEC AD-UP220-AE Power Supply

I was wondering if any of you electronics geniuses out there might be able to help me identify the surface mount diodes D2 and D3 or recommend the correct type of diode to replace them with? This is a switching power supply using a pair of STP14NK50ZFP mosfets driven by IC2, an L6598D controller IC. It has 22 ohm gate driver resistors, and the diodes are across the resistors. I've had a couple burn open so I replaced them with the ones from a 2nd board trying to make one good one out of the 2. I replaced the blown fuse, shorted mosfets, the driver IC, and one of the 22 ohm gate driver resistors that had burned open, and it immediately self destructed again upon powerup. I don't have any more spare diodes to give it another go so I need to purchase a suitable replacement. I did include a picture of one with IC2 removed so you can see where the traces go. There was some slight damage from the excessive glue on the bottom of the IC but the only pad lost was for Pin 13 which is N/C on that IC. Also if anyone can suggest anything I may be overlooking causing it to blow up, I'd definitely appreciate it. I had the exact same problem with the other one which is now a parts board so I haven't had any luck with these. BTW this section that keeps self destructing is for the 24V output. The 12V section uses a single STPNK60ZFP mosfet driven by IC5 an L6565D and that section doesn't see any damage on powerup. There is one more IC on the board, IC1, an L6562 that I'm not sure exactly what it does. I've never replaced that part on either board so I may order some and replace it for something to try. Also some background on the original problem, the main high voltage filter cap C8 was blown open so I'm sure the IC's were subject to a lot of AC ripple which may have destroyed them. That's why I'm thinking it may be worth a try to shotgun IC1. But please let me know if you have any further ideas. Thanks!

[Keshenatech1]

Re: UMEC AD-UP220-AE Power Supply schematic needed

Thanks much for the reply. Yeah I'm a member of the slot tech forum and I've looked at those posts already along with the repair kit and everything on the list is good as far as I can tell. Other parts are blowing and I'm mainly looking to identify D3. I just made another post with pictures in the troubleshooting section of this forum. But I definitely appreciate you taking the time to try to help.

[CapLeaker]

Re: UMEC AD-UP220-AE Power Supply schematic needed

I am sure others are going to chime in here soon.

The resistor and diode on the gate allow higher capacitance on the gate of the mosfet, affecting turn on and off times. If push comes to shove you could look for a lower capacitance gate on a Mosfet replacement and get rid of the resistor and diode by putting in a 0 ohm resistor and drive the Mosfets straight from the driver IC.

[Keshenatech1]

Re: UMEC AD-UP220-AE Power Supply schematic needed

Well I finally got both power supplies working. On all previous attempts, Q2, Q3, and the driver IC, IC2 would immediately short out and blow the fuse. There's another IC in that circuit, IC1, which seems to be in part of the feedback loop, and I hadn't previously replaced it. It's an L6598D. I guessed it probably got damaged like the other 2 SMD IC's in the circuit. The initial problem was the main 400V filter cap on the bridge blew out along with some smaller caps so I'm sure there was a lot of ripple and spikes pounding those IC's. For the diodes, I just used a 70V repetitive reverse voltage SOD-123 (Because my supplier was out of 100V with a long lead time), a 1N5711W-7-F. It looks and reads different than the original with just over a .35V reading on my meter in the diode scale, and the originals read .56V but the circuit is functioning. Ran the monitor over 10 min. and nothing blew up. Previously it would self destruct instantly on power up. So now I have a complete spare working monitor on the shelf and another spare power supply to change in the machine which is much easier than changing the big heavy 32" monitor. This one was a long time coming and definitely a W for the day, especially on a Monday!

[CapLeaker]

Re: UMEC AD-UP220-AE Power Supply schematic needed

Congrats! Good to hear you were able to get it sorted out!

[R_J]

Re: UMEC AD-UP220-AE Power Supply schematic needed

IC1 is the PFC drive ic. Check the voltage across the main cap (C8), if the voltage is 165vdc, the pfc is not working or in standby, When the PFC is ON, the voltage across C8 would be around 385vdc
IC5 seems to be the standby driver ic.
A lot of times the gate diodes are 1N4148w RHG (sometimes they are a zener diode)

[Keshenatech1]

Re: UMEC AD-UP220-AE Power Supply schematic needed

Oops I listed the wrong IC P/N in my original post. The last one I replaced that got them working is an L6562D, an 8 pin PFC controller IC. The 16 pin L6598 is the first one I had replaced that kept getting destroyed on power-up along with the driver MosFets. But after replacing the L6562D, it runs without self destructing.

[stj]

Re: UMEC AD-UP220-AE Power Supply schematic needed

unless these are fan-cooled, that design is going to cook the caps.

what is it fitted into?