It's nothing, it's a gold and field power supply. 100 degrees ahead, no circuit maps, no examples of repair。
One video streamer was seen, and three videos were not fixed, allegedly short-circuited by the main transformer。
The computer used to break a number of airline power sources, and it was very simple to fix all of them。
Maintenance begins:
1 there is no apparent problem with visual circuits。
2 measuring key: capacitors, resistance, power tubes, shortki diode tubes. No problem。
3 when the fan turns, measure the peak voltage. It's about 10v, 4v, 3v。
This power is controlled by ic 7520 and cannot be protected to measure critical point voltage。
4. Production of 3. 3 v and
5. 1 v and
3. 9 v
Small circuit, plus ic (7520) 1, 2, 3 feet.
5 when power is activated, 3. 3v voltage is measured to 4. 2v。
6 measurement of 12v, 5v voltage normal。
Looks like 3. 3v is under pressure. 100 degrees later, we found out what the magnetic magnification circuit was。
7 the measurement of the key parts of the magnetic magnification circuit was measured at a negative pressure of around 7v on the second tube end。
That's when the problem arises, when measuring the crystal triode: 3. 3v is normal。
It's malfunctioning itself, but the danger is still there。
8. Magnetized circuits containing more than a dozen elements, each of which is rewelded over and over again。
9 replace a733 with 2n5401
10, clear the slag of the original weld。
11, reloading test no problem。
To this restoration。
Magnetically magnified circuits control the current of a dozen. A large power tube was saved。
