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OK, John, thanks. Raymond

I'm not at the computer that has the PDF's right now so I can't check. I know for certain I have the schematics in the printed manual but they're 11" x 17" which is too large for my scanner. I should

The L we are interested in is the inductance that the power supply presents to the power line. In the case of the 2465, that is very low, in the tens to hundreds of micro Henries. Insignificant, in so

Thanks a lot for that document Hakan, priceless.... Vincent Trouilliez

These scopes were made to operate over a wide temperature range. A thermistor's cold resistance can become very high at the low end of the temperature range, perhaps high enough to make it unlikely to

It's a known problem and I think it has been discussed here before. There were a few WW articles written on the subject. You can find them here:

Hi Steve: I can help you with your knob problem.? First, remove it and clean out any plastic residue from the skirt on the knob.? Then carefully apply a small stream of super glue around the inside

Thanks Chuck Help me here: You wrote: it would be chosen to have a capacitive reactance equal in ABSOLUTE VALUE to the inductive reactance of the load it switches. 1. Using the formula (with 230VAC,

Hi Chuck, Where does a shunt resistor go relative to the thermistor? I thought the thermistor was the only component in an inrush current limiter. Is that incorrect? Thanks, Barry - N4BUQ <snip>

A snubber capacitor is a capacitor, used in conjunction with a series resistor, to dampen, or eliminate the back EMF transient caused when an inductor abruptly loses its current source. They are

I have now seen two 2465 PCB blocks with a burnt-out on/off switch. The damage is caused by the arcing across the now-separating terminals, when the machine is switched OFF. Replacement is easy with

Hello, I am looking for a volts/div knob for my 485. Plastic has degraded and skirt is loose. Thanks! steve_tech@...

You can use some small flexible plastic tubing to locate the noise. Hold one end to your ear, and use the other end as a probe to localize the source. Michael A. Terrell

Vincent,? Try replacing the FET first and see what happens.? Sent from K5JLR

Hi Dimitri, Had a horrible high-pitch noise in the SMPS of my 2215, though was from cold, unbearable (I am only 40 so I still hear this kind of noises...sadly). Power rails were all spot on and ripple

Same here. Dumont black-n-white TV was particularly loud to me. Funny, I can't hear that my LED TV. :) Thanks, Barry - N4BUQ

it When I was a kid the line whine from the TV at 15.625kHz (UK) used to drive me nuts. Now in my early 60's those days are long gone! I think I still have a good chance of hearing the older 405-line

Look through the archives for "singing power supply," and related links and discussions. I posted quite a bit of info on this a few years ago. Ed

Oops - one more thing. While looking at the old vacuum unit some more, I saw a second solenoid valve and remembered I added it for vacuum-hold, to prevent run-back through the pump. The pump has no

DS 1)As long as the Supply Voltages and Ripple is in spec too soon to talk about recapping 2) Most likely your hearing the whine of the power supply oscillator ( at my age I couldn't hear it anyway)