I have a monitor on which the power supply has failed, tryed repairing it and still keeps burning resistor so I give up, and its not in the monitor circuitry cause its separated via small transformer, which is driven somehow, that differs from linear power supplies MONITOR IS RATED FOR ABOUT 30W
Now what Im gonna do is build a completelly new power supply to substitute voltages that should be 1.3 V
6 V
14 V
45 V
70V
all should be AC,now I can use common power transformers except maybe for 45 and 70 Volts, what would be the easiest to get these votlages ??
>>1015848
>what would be the easiest to get these votlages ??
with a transformer.
>>1015851
yes but 70V is not a common output on transformers like 12V is , the highest I have is a 50V one
also wiring my own or have it down would cost too much,can i use a circuit doubler, or maybe a power resistor droping ?
>>1015856
50V + 20V = ?
>>1015866
I dont think he wants 5 different power transformers power one little monitor
also sounds like it would chuck a decent amount of electricity
>>1015868
it sounds to me like OP couldn't find the problem and went HULK SMASH on the power supply.
I don't know what he's trying to do, and I don't know what he needs 70V for, unless we're talking about a tube. (for which it seems a little low, but that shit was before my time)
>>1015848
what the hell kind of monitor is this?
![IMG_20160630_184418[1].jpg](https://i.imgur.com/jj53TXa.jpg "IMG_20160630_184418[1].jpg")
>>1015874
>>1015875
Its a 80s monochrome VGA monitor and what pisses me off is that I just finished cleaning it completely was adjusting the pots and the last one was a B+ adjustment on the power suplly and my screwdriver slipped and I shorted something out the fuse blow the circuit breaker went out and that was that
As you can see in pic that is what I replace in order to try getting it working but no sucess, you cans ee were the power section is separated form the main monitor board and that transformer between. On the secondary of that transformer there are these voltages as output that go thru rectifiers into the caps seen in pic. I have a identical working monitor so I got those voltages from that one
Now all I got to do is make a power suplly that will supply identical voltages and my monitor should work again
any compliments ?*
bumps
>>1015885
that transformer outputs several voltages. i'm sure you can salvage it.
>>1015885
Dumb question, but does the B+ pot still work? If you shorted it to HV, you might have toasted it, at which point the power supply is going to keep failing because its calibration is busted.
>>1015909
ITS SOMEHOW DRIVEN THRU A COUPLE TRANSISTORS whcih i DONT HAVE A CLUE OF
my best option is to build a nice linear power supply, atleast I would understand what Im doing
>>1015910
Ive shorted the housing of that pot to that resistor closest to it
>>1015912
>my best option is to build a nice linear power supply, atleast I would understand what Im doing
kden.
>>1015916
yes but I dont want to use 5 transformers for each output is there an alternative
>>1015922
Multiple taps on the secondary?
Check out Power Integrations website for tools and application notes if you're serious about this.
I warn you though, transformer design is a very advanced topic.
>>1015951
good thing Im in first year at EE university
>>1015885
>my screwdriver slipped
and that's one of the reasons you adjust post with plastic screwdrivers, m8
>>1015848
>I have a monitor on which the power supply has failed
"power supply" or the HV?
HV on CRTs dies when the tube is dead. The doping on a CRT cathode has a finite life, and when it's all used up, the CRT's electron gun can't source any more electrons and stops working. At that point the HV blows out.
You can fix the HV as many times as you want and it will keep fusing out unless you replace the tube too.
