Re: DSLR canon sl2 flash error 50
If the base trace is disconnected, you won't go anywhere with continuity. Try to follow the trace visually.
raider988
Member
Last Activity: 03-01-2021, 05:19 PM
Joined: 07-18-2015
Location: N/A
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Re: Dyson Cyclone v10 - Brushes not working
Just a little update on this repair in case anyone will have the same problem in the future.
I managed to remove the board but gave up on tracing the problem, the whole board is covered with an insulating material and without a datasheet I simply gave up.
So I decided to bypass the circuit that controls the brushes. After some trial and errors and a little bit of learning I came to the conclusion that the brushes are controlled with PWM signal. The bushes are DC 16.2v, 50W.
I understand very little...Leave a comment:
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Dyson Cyclone v10 - Brushes not working
Hey everyone,
I have this portable vacuum cleaner that works just fine, except for the attached brushes that are completely dead. The vacuum motor has 3 speeds, but the brushes always worked at the same speed regardless. After a quick check I realized that the brushes are not getting a way to ground when the cleaner is on.
I accessed the motherboard and started probing around. Unfortunately, I didn't fully remove the motherboard because my iron is not powerful enough to melt the solder connection to the motor (vacuum) in the center of the board. The board was just soaking... -
Re: LPK12-450W safety capacitor shorted
I don't really understand how could it be legal to rent/sell house without outlets properly grounded.Leave a comment:
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Re: Toshiba Satalite C850 lack screen after LCD replacement
I'd check also R3035, it might be pulling the line to groundLeave a comment:
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Re: Soldering station thoughts and guidelines
Yes, it's about 150$ the station alone, plus a decent transformer, a case and the iron.
It would about 250$, but are they worth?Leave a comment:
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Re: NordicTrack C700 Treadmill Dead Console
Just to be sure, you should test that the power supply is doing its job, disconnect it from everything it's supposed to power up and test the 12v line with a load, I'm still on cheap side and use led strips because i can easily change the current required by disconnecting parts of it.
You should remove the gue from the main board and desolder the 12v, check continuity on the cable. Continuity is your friend, if you can't find a datasheet for the board (which seems multilayered), than start sticking the probles around following...Leave a comment:
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Re: Nientendo 64 PSU - Secondary side dead
Thanks R_J! I have a new update.
While waiting for the components to arrive I thought that I might as well retin the SMD components. You wouldn't believe it, the power supply came back to life. I don't know why I didn't think of doing that before, since I already retouched all the through-hole components. I attached an LED strip as load to the 12v line and it outputs up to the 800mA as it's supposed to. Since the daughter board is next to the heatsink (the closest part is the right side of the last image I attached) of a...Leave a comment:
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Re: Soldering station thoughts and guidelines
Looks like I'm a year late for the party... but anyway, has anyone tried to buil the Unisolder from Sparkybg?Leave a comment:
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Re: Nientendo 64 PSU - Secondary side dead
Hey guys, finally I'm getting closer to solving the problem. I'm a little ashamed to admit that I cheated my way out of it. I borrowed the same power supply from a friend and the circuitry was exactly the same. I swapped the small daughter boards and the power supply started working again. Then I combined the FB of the working board to the PWM of mine: the PSU worked.
So my problem is on the feedback side, I replaced the optos and checked every resistor and diode, comparing the results of the two boards, everything seems...Leave a comment:
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Re: Nientendo 64 PSU - Secondary side dead
I replaced the the transistor and nothing changed.
I noticed a coupled things, even without delivering any output voltages, the PSU uses about 400mW. Since I monitor the 400v bulky cap after unplugging, I noticed that when it discharges to about 100v, the PSU emits a tiny nise, like a small short and the big cap gets discharged instantaneously to about 15v. I removed the fuse shown in the datasheet I draw and masured the breakdown voltage of the zener, which was about 15v as well. Maybe a bad zener is creating the problem?Leave a comment:
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Re: Nientendo 64 PSU - Secondary side dead
I checked the transistor, it still reads fine, later I'll swap it with a new one, just in case.
I still don't understand how increasing the resistance of RSENSE would make the supply deliver the correct voltages. As far as I understand, the purpose of RSENSE is to signal PWM when too much power is being drawn, which would explain why, with a higher resistance, hte PSU couldn't deliver more than 40mA onthe 12v line. But it still doesn't explain why the PSU doesn't work to begin with.
I'm getting more and more convinced...Leave a comment:
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Re: Nientendo 64 PSU - Secondary side dead
This is the schematic, T1, T3 and T4 are the transformer's pins, from left to right. Could it be that there's something wrong with the feedback/PWM circuit?
Edit: sorry, vertical image. I checked the internal resistance of my multimeter and was about 0.3, thank you for the trick!...Last edited by raider988; 06-07-2019, 10:18 PM.Leave a comment:
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Re: Nientendo 64 PSU - Secondary side dead
Hi RJ, the NPN reads correctly, I found out that there are 3 types of to-92 BCE configurations, so I concluded it was my fault in getting the wrong datasheet. On the board, the image of the transistor and marked location of the emitter matches with the reading I get, under the assumption that I mistook the base for the emitter.
The resistor reads R27J, so i thought 27Ω with a 5% tolerance. I tested the power supply with a 27Ω resistor, it outputs the correct voltages, but very low current, not more than 40mA on the...Leave a comment:
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Re: Nientendo 64 PSU - Secondary side dead
Solved. The 27ohm sense resistor failed short, I initially thought it read low because I measured in circuit, but once i desoldered it I found out it was damaged. I temporarily replaced it with a 1/4w (I don't have a 1w at hand) and the power supply came back to life. I guess what happened is that the PWM was sensing too much power was beeing pulled and shut down the current to protect the components. Thanks for the help STJLeave a comment:
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Re: Nientendo 64 PSU - Secondary side dead
I started desoldering some components to test them. On the primary, there's a transistor marked D1302 s .71. It's NPN, I checked the datasheet and I'm not sure if the transisor is bad or the pinout is wrong, because it makes no sense that its base is connected directly to ground. This are the values I'm reading (following the pinout from the datasheet):
BE: OL
BC: OL
CB: OL
EB: 0.69v
EC: 0.69v
CE: OL
Edit: On the board, next to where the "base" connects, it's marked with...Last edited by raider988; 06-07-2019, 05:35 PM.Leave a comment:
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Re: Nientendo 64 PSU - Secondary side dead
Yes, it's a small 22uF 50v. I replaced it and since there are only 5 electrolytic on the whole board, I just replaced them all. No results. I also retouched all the connections, again just in case. Still nothing happened.Leave a comment:
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Re: Nientendo 64 PSU - Secondary side dead
Hey thank you for the quick answer! It's a small 472k 250v (looks like a class y to me)Leave a comment:
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Re: Nientendo 64 PSU - Secondary side dead
On the primary there's only a chunky 400v 47uF electrolytic cap, 2 class Y and a small film cap, which ones do you mean?Leave a comment:
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Nintendo 64 PSU - Secondary side dead
Hey guys. I have this PSU with the secondary side completely dead and I need some help in troubleshooting and I couldn't find a schematic for it. I'm still a beginner in electronics so please bear with me.
There is no visible damage to any component, the PSU is reasonably clean with no burnt smeel whatsoever. The secondary side seems completely dead, I couldn't find any voltage anywhere, not even at the transformer's terminals. It seems as if the transformer is not doing its job, maybe because it's bad or because it's not told to switch on .
Here's what I checked...
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