yx-305d bench power supply decreasing voltage problem

[ashan000]

This power supply is 30v 5amp. Problem is when turned on after about 3 minutes voltage starting to decrease slowly. (like - 5.8 > 5.7 > 5.6 > 5.5) can't see any damaged component or dry solder joints. Checked main 2 transistors with multimeter. Reading seems ok. Tried changing potentiometers(both coarse and fine) still the same situation. Can any one help me to troubleshoot? What voltages to check? Any ideas helps to fix this. thank you.!
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[juan667134]

If someone helps me with the scheme please lenovo...

[karim011]

Hi everyone. Plz needed bios & EC HP Pavilion Gaming Laptop. Model : 15-ec2001ns S/N : 5CD1213PSO MB : dag3himb8c0 rev c

[jimbofz]

has anyone ever had to replace the SVC chip on original xbox? 1.3 version
i have fully recapped main board and eliminated psu with working original
and checked the print for corrosion caused by leaking clock cap ect

box will start up fine when the SMC ic is frozen with freezer aerosol spray
but otherwise it just wont start,
sometimes the fan will spin if you keep holding the power on button
but it wont start up
i would value your opinion thanks...

[arsharpe]

Hi,

I am fixing the charger (UC18YKL) for a Hitachi battery drill (DV18DCL2) but, as it charges Lithium batteries, I need to know the correct replacement device for the blown (smd) FET2.

As I have spent many hours trying to find a schematic for this DV18DCL2 charger without any luck, does anyone know where I can get one or a parts list?

Thanks in advance for any help,
Rob

[Peter_1402]

Hi Everyone,
I bought a Yihua 992DA+ hot air gun and soldering iron unit from a used market.
1. Soldering iron works great
2. There is a burnt mark on the hot air gun handle.
I am a bit concern by the look of the melted plastic. I opened the hot air gun handle and took some readings with a multimeter.
Heating element ~ 75ohm. (Similar reading taken from a spare heating element that came with the unit.)
Thermocouple ~ 1.5ohm. (Similar reading from the spare heating element.)
Reed switch tested ok with a magnet.
From the above test, I can conclude...

[madan1]

Good day.
I'm currently on a vacation and a friend from the camp site asked me to check why his camper power supply does not charge the batteries when hooked to the mains.
The PSU is cramer and from what I've found the same mainboard is used in both cbc-b7 and bcc-b7. The control module/interface panel is Cramer D-5750.
So what I've found so far - the transformer seems to be working fine and the board has no visually damaged components. I tested most of the diodes and transistors with a multimeter (the only tool I got here) and they read fine.
The two thyristors have been...

[angelos]

Hi Guys,
I have this 2008 lcd tv that uses ccfl lamps. The tv is stuck on standby. This is what I have noticed. The standby 5Vs voltage is not 5V but rather 3.28V. There is a 14V rail as well but that measures ok. I put my volt meter on the 5Vs rail and switch on the 220Vac. I noticed that the 5Vs rail goes to 5.1V and quicky changes to 3 28V and steady.
I unplugged the main board and ccfl lamp wires and tested the power supply separate from the tv without load and put a 470 ohm resistor to the stby rail to force the tv on.
1. Pfc circuit activates and mains smoothing cap is...