I have a couple transformers on this board I'm working on and all but a couple (which I don't think are connected to anything) show continuity to ground. Surely not all of them should go to ground right?
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Re: Transformer pins common to ground
It may not matter - if they are not connected to anything in the transformer. It is just a locating pin soldered to help anchor the transformer.Please upload pictures using attachment function when ask for help on the repair
http://www.badcaps.net/forum/showthread.php?t=39740 -
Re: Transformer pins common to ground
Hmmm....I didn't know that. So if I suspect something from a transformer sounds like it's always a good idea to pull it and inspect. Thanks.Comment
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Re: Transformer pins common to ground
On the secondary side of the transformers (I.E. two power supply with common ground ref on the secondary side) one pin of each transformer will be connected to the secondary side common ground, the other end of the transformer winding will feed for example the Anode of the rectifier Diode. So if you take the resistance reading on the Anode pin of one of the transformer to another Anode of the diode of that is connected to the pin of the other transformer, it will show low reading due to low DCR of the transformer winding.
Best way to learn is to draw up the schematic.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=24809Comment
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Re: Transformer pins common to ground
As you say I think you have to suspect it first else it is a lot of effort. You dont say what
type of transformer main power?, inverter? Inverter ones often have 2 spare legs
some have more.Please upload pictures using attachment function when ask for help on the repair
http://www.badcaps.net/forum/showthread.php?t=39740Comment
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Re: Transformer pins common to ground
Example Diagram.Attached Filesif you find these attachements useful please consider making a small donation to the site
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=24809Comment
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Re: Transformer pins common to ground
Thanks bud I will study that. I can't get schematics on these things. I'm not sure what type of transformer. I've tested transformers in school but never had to identify ones in tvs. But most of the pins running from the transformers are in the same trace on the board and they all run to ground.Comment
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Hi there !
This is my first post out there, glad to be part of the community.
I was gifted an old analog mixing unit (from the 70s) by a good friend. It's a Neptune Audio Mixer model 611, 6 channel mixer with :
-6 XLR inputs wired hot to 3, and 1&2 to ground (which is already a weird start. You can see this in Picture 3, and all sockets are what I understand to be common ground, as there's a long wire connecting all XLR grounds together. Besides, all Hot are connected to the other pins via a cap with the marking 24 102k)
-6 unbalanced... -
Back in 2020 i bought a (2nd hand) compact ATX psu to replace my current one. My PC case only fits very short ATX power supplies so i didn't really have the choice of buying a decent 80Plus unit. The current unit is a modded YoungYear unit that i made a thread about a while ago:
A "nice" YoungYear unit? - Badcaps
The "new" unit is a KDM-M6480 480W psu, the 480W number is a typical KDM bullshit claim of course, but the 24A rating on the 12V rail seemed reasonable and the "Active PFC" claim gave me a bit of hope that this was going to be decent-ish.... -
mon2 Thank you for your very helpful posts. Could you point me in the right direction? I have a thinkpad e15 nm-c421 that i got with a loose jack that couldn't get a charging light in any position.
After replacing the jack, i get 5v to the board, but no amps at least on my cheap tester and the light goes out after first lighting up(on the tester,but plug light stays on). I have no shorts to ground or between pins on the jack itself, but the diode mode red on ground does seem off on a couple pins based on what was posted above. Pins 10 and 11 rx2n and rx2p have no reading, OL, but they do... -
Hello, I received to repair this Huawei laptop (model in the title).
The laptop will charge the battery fine throught the USB C port, but it wont turn on. The charging led will blink fast and repeatedly when trying to turn it on.
I've attached photos of the board. (the wires are for briging the power button, I did not inject voltage)
Upon visual inspection, a couple of ICs were blown. Along the 5V line leading to one of the USB A ports. They wasnt fully shorted but just a couple of ohms to ground.
I replaced the blown IC on the board (the one circled in red,... -
Good day everyone.
I have on the bench an amp board from DALI SUB E-12F. It is class D amp with a smps on the same board.
The issue is that it powers off way before the rated power is reached (the protection circuit kicks in). It has an independent standby power supply, which stays on after the main power supply is turned off via a relay on the primary side (thus there is no reason to believe that the protection is triggered from the smps IC on the primary side).
The normal value of the positive and negative power rails is +/- 43V.
The positive rail stays...
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