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Re: OT: Seeking help reviving a Stanford Research Systems SR760 Spectrum analyzer
OK, John, thanks. Raymond
By Raymond Domp Frank · #150235 ·
Re: OT: Seeking help reviving a Stanford Research Systems SR760 Spectrum analyzer
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
By johnasolecki@... · #150234 ·
Re: Snubber capacitors
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
By Chuck Harris <cfharris@...> · #150233 ·
Re: 2235 - high pitch noise
Thanks a lot for that document Hakan, priceless.... Vincent Trouilliez
By Vince · #150232 ·
Re: Snubber capacitors
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
By Chuck Harris <cfharris@...> · #150231 ·
Re: 2235 - high pitch noise
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:
By zenith5106 · #150230 ·
485 Knob
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
By Reed Dickinson · #150229 ·
Re: Snubber capacitors
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,
By M Yachad · #150228 ·
Re: Snubber capacitors
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>
By n4buq · #150227 ·
Re: Snubber capacitors
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
By Chuck Harris <cfharris@...> · #150226 ·
Snubber capacitors
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
By M Yachad · #150225 ·
Tektronix 485
Hello, I am looking for a volts/div knob for my 485. Plastic has degraded and skirt is loose. Thanks! steve_tech@...
By Steve Lindberg · #150224 ·
Re: 2235 - high pitch noise
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
By Michael A. Terrell · #150223 ·
Re: 2235 - high pitch noise
Vincent,? Try replacing the FET first and see what happens.? Sent from K5JLR
By Leon Robinson · #150222 ·
Re: 2235 - high pitch noise
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
By Vince · #150221 ·
Re: 2235 - high pitch noise
Same here. Dumont black-n-white TV was particularly loud to me. Funny, I can't hear that my LED TV. :) Thanks, Barry - N4BUQ
By n4buq · #150220 ·
Re: 2235 - high pitch noise
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
By Craig Sawyers <c.sawyers@...> · #150219 ·
Re: 2235 - high pitch noise
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
By Ed Breya · #150218 ·
Re: Desoldering Iron vacuum
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
By Ed Breya · #150217 ·
Re: 2235 - high pitch noise
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)
By Dave / NR1DX · #150216 ·