Problems, Lots of hum. Can't find a schematic on this one. It uses 2 BEU7's 4 12au7's and 2 7191's for the output. I can remove every tube except the outputs and still hum. Checked a lot of voltages and everything seems ok. Still hum. Replaced the 20uF filter caps. Still hum. Tried a new set of outputs. Still Hum. Any ideas? There's not that much to it.
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Re: 1965 Gibson Hawk w/ 7191's in the output
Could it be a ground loop hum? I can't say I am very familar with anything about guitars or guitar amps. I do know though that they are very common on stereo equipment. I know that there are things that are called ground loop isolators that would take care of that. I am sure that more than likely you have thought of that but still thought I would ask. -
Re: 1965 Gibson Hawk w/ 7191's in the output
main filter caps open.
and those are 7591's in the output.
change every lytic and wax paper cap in it and report back.Comment
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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... -
It has been a long while since I posted here to ask anything....hope you can help.
I have this Samsung power supply that uses SPC1012T as driver for the PFC and it's giving me a problem that I can't narrow down though I've troubleshooted and fixed hundreds of boards similar circuits.
I am attaching a schematic from a different Samsung board, but the topography is very very similar if not 100% the same and it uses SPC1012T, which BTW is a pinout match to UCC28063 for which there's plenty of information. I haven't confirmed they are functional equivalents, but I strongly... -
I have here a Magnum IA.100 which belongs to my parents.
The unit powers on & when the relay kicks in, you get a pop from the speakers (this might sound weird but is usual behavior for this amp). However, you get nothing coming through it from any of the inputs & no pops and crackls from any of the controls.
Because of the sound from the speaker when the amp turns on I have assumed that the output section probably works but I could be wrong & I'm not sure how to test that side of things further.
What Ive done........01-01-2025, 01:26 PM
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