When a control board sends a signal to the psu how does the psu go into full activation? Does a transistor turn on a transformer at that point?
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Re: How the smps goes into full mode?
In typical power supply, the signal from the main board will turn on the transistor which in turn, turn on the Opto-isolator (LED inside the Opto is turned on, the Opto is used to isolated the primary side from the secondary side which the main board is in), this will turn on the Photo-transistor inside the Opto-isolator.
This Photo-transistor is then turns on the switched transistor that supplies the B+ to the VCC pin of the SMPS IC, once the SMPS IC get the voltage to run, then it will send the drive voltages to drive the Gate of the power MOSFETs which drive the power transformer to produce the stepped down voltages which are then rectified by the diodes on the secondary side of the transformer.
I.E. SCH
I hope you know how to read SCH.Last edited by budm; 02-24-2014, 10:37 AM.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=24809 -
Re: How the smps goes into full mode?
Thanks bud, I'm still studying the diagram.Comment
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This relic from a technology path that came to a dead end (but still has historical interest) was brought in with a dead SMPS, which is based around a MK1210 device. I got it going after a battle. It seems to have a strange design - if it's not getting feedback that the secondary is OK it cause the big FET to go into full conduction and overloads resulting in a blown fuse at best or something worse! I'm using a Dim Bulb Tester (70W/230V) which thankfully has saved the day a number of times whilst repairing.
Now, it loads a CD OK. The motor voltage output (which is built onto the SMPS... -
Hello
Got this speaker from a friend , defective. Power led comes on and off , in a loop.
Disassembled, got the board out, and after a bit of measuring I found a low resistance on a 5v6 line. With a bit of current I found a transistor heating up on that line (labeled T1 and 113 as on pic).
After removing this guy, I got a value of 0.7 in diode mode on that 5v6 line, which before had 0.02 or something like that.
I tested powering it up without the IC, and the speaker turns on and stays on, and works fine
Still, I need to replace this transistor.... -
I have this Huntkey HK340-72FP PC SMPS where I am facing a strange problem where the SMPS shuts down when the load on any of its 12v output rails goes above 2 amps while the rating of each 12v rail is above 10amps capable.
I have checked the following:
1. All output caps are OK, and all output rails read correct voltages at no load
2. All output diodes are OK
3. NTC is ok
4. Hi voltage cap on input correctly reads 150uF on LCR meter per the spec, also the bridge rectifier is OK
5. No short in main switching MOSFET
6. All other components... -
hi people, i need some help to identify a transistor(q14) that is missing on the board, so the gpu has no voltage i think that q14 activate the phases for gpu, but i dont have schematic or boardview, but i think its the same transistor than q15 and q16, thanks... -
Hello,
I'm troubleshooting a PA speaker Mackie Th15 (schematics attached).
It is basically a smps with amp and some dsp.
The issue is that on the secondary side I read +/- ~23V instead of the expected +/- 38V. Indeed all secondary side and feedback/aux rails are like 1/2-3/5 of the expected values.
Q2, Q3, C35, C40, C33, C36, C41 and C42 were tested out of circuit with a component tester and read fine. Most of the other components on the primary were tested in circuit and seem to be fine. +HV to -HV on primary is ~330V.
By the way, the ferrite core of L10 is broken,...
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