The low voltage side of the power supply. Just saying IF there is something wrong in the primary, it would have exploded in your face or there is an open circuit somewhere and is dead as a rock.
So the primary side works. The low power secondary has something wrong with it, Where does this little board hook up to… looks like into the secondary somewhere, as it got DC leads….
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Usually a chirping in the power supply means there is something shorted in the secondary, as the PSU starts, shuts down, starts again and shuts down again. Over and over, wash rinse, repeat.Leave a comment:
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8v lamp on a 48v supply?
i'm kind of glad it didnt work or you would be sweeping up glass!
you cant tell if a cap is good by looking, and YXF is low end for a psu - i would be using rubycon ZL or panasonic FR
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I have no clue of what I'm looking for, but I used the search on this website and found this:
Does this mean that the pictured caps are bad and should be replaced?Leave a comment:
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I've connected the output of the PSU to an old projector bulb (8V 50W) and got the "chirping" again!
Do any caps on this PSU look like they need replacement? If not, should I desolder them one-by-one and test using a capacitor meter?
Thank you for your help so far! Happy to carry out more tests and learnLast edited by tester001; 12-07-2023, 09:27 AM.Leave a comment:
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the small board may regulate the current.
it's a fixed but ajustable current supply, so the voltage can move around a bit.
i would test the supply without the small board by using a light bulb - 25w or 40w, as it's only rated to 60w.
a old style filament lamp - not a halogen or led etc.Leave a comment:
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PLP-60-48 Single Output LED Power Supply - "chirping" noise
Dear Badcaps forum members,
Hope that you are all well!
I am a newbie on a mission to figure out the cause of the PSU making a "chirping" noise:
Having searched for this symptom online I have found some indication that failed capacitors may be an issue. To help with the troubleshooting, I have tried to isolate the problem and disconnected the PSU from the rest of the device - the chirping remained.
I have then found that the whole PSU (apart from a small add-on board) can be replaced, and there is even a datasheet for it: https://cdn.badcaps-static.com/pdfs/...72e3c7c9cd.pdf
I then removed the small add-on board and the PSU started without chirping:
The output should have been 48V, but I don't know what to make of this reading (is it even indicative of the PSU health? perhaps only putting a proper load on it can tell).
Once I re-attach the small add-on board (even without connecting the full load!) the chirping returns:
The white terminal on this board connects to the PSU output and the red/black wires then feed the actual device.
What could this behaviour mean? Is the problem in the add-on board? Can the presence of the add-on board create a sufficient load for the problem in the PSU to manifest itself?
Thank you in advance!
Tony
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Good morning everyone,
I'm trying to repair an onkyo ht-r390 that has no sound output, despite the volume being at maximum, the rest seems to work; the video output signal (coming from an hdmi input) is present, but the audio is absent. Similar situation if I send an audio signal from any input I have no output.
The firmware reported is the following:
M:1.00/11107BLP
D:?.??/????????
O:1.00/11107AL
The DSP firmware given the question marks seems corrupt.
On the BCHDM-0678 - 25140678 - QPWBCHDM0678A0 board the chip that usually seems...05-11-2025, 02:59 AM -
I have bought this Zener Diode for this project what size and wattage resistor value do I need to use to get near 50 watt output
I bought this from an eBay seller but unfortunately they only had one
I bought three from Vetco Electronics these are Sylvania ECG5185A 9.1@10w A to Stud what size and watt resistor do I need to use to get near 10 watt output
I bought three of from them to also make battery packs with this output power limit in mind
I want to use this battery pack and turn it into a 9.1 output battery pack output to eliminate using 9 volt battery... -
Looks like I may need a little help from the PSU experts (or anyone really!
) I have a Corsair CX750M (Model 75-002019) that I picked up for free about 4 years ago. This is the PSU:
So here’s what’s strange about this one: it appears to work normally (normal output voltages) and any PC is stable with it. However, after a while (typically 10-20 minutes, but time can vary depending on the load), there is a sweetish smell of burned magnet wire insulation emanating from the PSU. Upon opening the PSU after this happened (many times), I was able to confirm... -
Hi:
I bought this amplifier from the 70s to try to repair it. So far it has no output sound, just noise. You can volume it up and down.
I've checked fuses and all are ok.
I've continued with capacitors:- The main black one should have 4700uF, but it has lost half of its capacity during these years.
- The ones that I've numbered have still a really low ESR and the full capacity after ¿40 years?
The 4 transitors are perfect. Desoldered and tested individually.
There are also components which I don't know exactly what they are.... -
Surprisingly enough, this receiver doesn't have the DSP chip issue. The HDMI board does not get hot, and sound over HDMI works fine.
Regardless of the input, the right channel has noise that is clearly noticeable even on average volume level. The only cases when there's no noise is when VCR input is selected (some tracks on the board are damaged, maybe that's why), or if HDMI input is selected but nothing plugged into it. In all other cases, even when no input is connected I still have the noise.
There's some logic behind it. As soon as I select an input I get only left...04-23-2025, 10:09 PM
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