What, are you daft? It is LITZ wire. (big hint, look at the wire spool) Each stand is insulated and that 15 feet is like $150.
https://www.newenglandwire.com/litz-wire-termination-guide/

At the risk of appearing daft-er ... what's special about said LITZ wire? Why is it important that each strand is insulated?

 

At the risk of appearing daft-er ... what's special about said LITZ wire? Why is it important that each strand is insulated?

LITZ wire improves the Q of high frequency loop (where HIGH frequency is relative to line frequencies and/or kHz to MHz range signals) circuits by reducing AC 'resistance' (reduce copper losses) as opposed to a normal solid or stranded conductor of the same effective wire gauge. For this project the 'line' frequency is 10 kHZ so the skin effect losses with regular wire can be easily seen when power levels are in the hundreds of watts when the magnetic field generation loops are only a few turns, low voltage and high currents.
If you've studied, designed, built and/or repaired RF or power transformation devices that need the best efficiency with reasonably possible engineering, LITZ wire will be on the menu if cost is not the primary driving factor. Each strand is individually insulated to reduce skin effect reductions in the current flow cross-section of a conductor (solid or uninsulated stranded) in conjunction with things like silver or gold plating of conductive surfaces.

https://agilemagco.com/blog/5-benefits-of-using-litz-wire/
Litz Wire: An Ideal Solution for High-Frequency Applications

 

What actual LITZ wire does is it provides a much greater skin area relative to actual total conductor area, since the skin areas of each conductor are in parallel. BUT I suspect that at some point there is a magnetic effect between the conductors. But the math and physics behind that guess I have not explored.

 

What actual LITZ wire does is it provides a much greater skin area relative to actual total conductor area, since the skin areas of each conductor are in parallel. BUT I suspect that at some point there is a magnetic effect between the conductors. But the math and physics behind that guess I have not explored.

That's why I paid through the nose for actual LITZ wire for this project. Some of us have explored the magnetic effects for practical applications.





Hall sensor current FFT.
CH1: Sony amp input power signal.
CH2: Hall current sensor of LITZ wire loop.
https://s3.amazonaws.com/amploc/PDFs/KEY100-AMP200-AMP300.pdf

For the 200A sensor: 115.8/9.5 for RMS current = ~12.19A at idle in the power transfer LITZ wire loop.

 

Repaired a broken "turn-on" simple wire inside an audio power amplifier salvaged from a Mazda RX7 that feeds signal to display Lissajous images on a CRT monitor attached to my home stereo.

 

Repaired a broken "turn-on" simple wire inside an audio power amplifier salvaged from a Mazda RX7 that feeds signal to display Lissajous images on a CRT monitor attached to my home stereo.

Back in 1962 I was given an older TV, that had a 10BP4 round CRT, that used an oscillator high voltage second anode supply, not a flyback transformer. So I built a usable oscilloscope out of it. I only used it for audio, I could have sine sweep or sort of liner sweep using an NE2 relaxation oscillator, a 12AX7 voltage amp and 6V6 transformer driving the vertical part of the scope. Another similar amp for the horizontal sweep. Quite a cool setup for a tenth grade kid.with no help from anybody.
Yesterday I changed the Mic input connectors on a100 watt BOGEN PA amplifier. I also had to replace the missing two of the four output transistors, # 2N3055 types. Now it works well driving a 100 watt horn speaker. Not music quality with that speaker, though. But loud.

 

Got a free Samsung 65" 'smart' newer television because its backlights were failing; and owner did not want to deal with a repair shop.



Ordered the $20 backlight strips and arrived and replaced them today.
Did the opposite procedure shown by youtube experts. Did not have to handle such huge glass fragility, have no glass suction cups to move it either. Left the display face down on a bed and detached / lifted the metal chassis instead, did not have to remove filters and shuffle difussers nor risked sandwiching hairs or lint this way. Very difficult and tricky with enough pauses to slowly examine details and a beer.
Works ! Am happy.

 

Got a free Samsung 65" 'smart' newer television because its backlights were failing; and owner did not want to deal with a repair shop.

View attachment 328939

Ordered the $20 backlight strips and arrived and replaced them today.
Did the opposite procedure shown by youtube experts. Did not have to handle such huge glass fragility, have no glass suction cups to move it either. Left the display face down on a bed and detached / lifted the metal chassis instead, did not have to remove filters and shuffle difussers nor risked sandwiching hairs or lint this way. Very difficult and tricky with enough pauses to slowly examine details and a beer.
Works ! Am happy.
View attachment 328943

It was the beer you had that did the trick ...

 

Got a free Samsung 65" 'smart' newer television because its backlights were failing; and owner did not want to deal with a repair shop.

View attachment 328939

Ordered the $20 backlight strips and arrived and replaced them today.
Did the opposite procedure shown by youtube experts. Did not have to handle such huge glass fragility, have no glass suction cups to move it either. Left the display face down on a bed and detached / lifted the metal chassis instead, did not have to remove filters and shuffle difussers nor risked sandwiching hairs or lint this way. Very difficult and tricky with enough pauses to slowly examine details and a beer.
Works ! Am happy.
View attachment 328943

They make great computer monitors!

 

Interesting how some of the yoo toob stuff is not always quite the best way.

 

Hi.
Replaced a dead power supply that feeds an audio amplifier driving the deflection coils of my home-brewed CRT Lissajous audio display.
It is back in operation. Done. Happy.
Edited. It is a 3 second video, but did not stick. Shows as photo attached below ¿?

 

Yesterday I fixed the vent fan for the grill at my friend's restaurant. The symptom was: stone dead, no noise when the switch turned on. First, I suspected the switch. 90 volts across it when open, 0.23 volts showing with it closed. So the feed was there. Up on the roof, 123 volts across the motor side of the safety switch. No motor vibration or sound.
I adjusted the variable speed control knob. It felt right, but no effect. Switched the safety switch off, bypassed the speed control. Safety switch on, motor running. In time for the later lunch crowd. Put the cover back on, now to see if it really needs a 2-wire, series, 120 v single phase, 1/3 HP speed reduction.
The motor is dual-voltage, reversible, single capacitor, induction motor. No start switch. Why do they need a speed reduction??? I have not found an expert on the topic yet.

 

The installer/vendor made more $ with that variable speed model ?

 

What I had guessed was that as a fan horsepower requirement varies with RPM, it might be that the speed is adjusted to a slower level so that the motor is only running at its rated load. BUT the problem I see there is that the motor efficiency changes with the speed, at least I think it does.

 

Repaired some old stuff.


VFD display module. https://www.oemsecrets.com/details/0360126240r





Oscillations on the DC output above 20A into a .33 ohm load. Isolated the problem but won't fix as the PS is 2X revisions obsolete.

 

Attempting to repair sons Electric dryer.
I think they are going a little over the top with appliances now, re processor controlled etc!
Is it really necessary?
The basic items are still there, an element and a Motor.
Things have certainly changed from the original model, a 100ft or so of double braided rope !!

 

WOW!!! NasaSpook certainly has very interesting things to work on, and evidently a fantastic tool set available. My "toy" budget is a lot shorter.
Yesterday I tried to repair an XFINITY tech's installation, in a rental property, for a pair of rather senior ladies. Evidently there is a limit as to how many splitters and how much kinked RG6 cable will allow adequate signal to a number of distribution points.
Earlier in the day I had investigated the failed variable speed controller for the vent blower I mentioned in post #252. What I discovered was that the switch in series with the control, part of the speed setting pot, had failed open. So I installed a solid jumper across the switch. The switch would not be used ever in normal operation, it is inside the motor enclosure of a rooftop blower installation, which has an approved safety disconnect switch on the outside of the housing.
So now the control can again be used to reduce the motor power input to it's rated level.

It seems that is how vent manufacturers match the motor ratings to the blower requirements.

 

Repaired my 24 years old Alpine car radio that had unobtanium schematic. Did not power on. Found a corroded open circuit via on the +12BAT trace after painfully dismantling its multiple pin rear connector and probing traces.
Stupidity designing the supply line trough tiny vias. Manufacturer technical support was of zero assistance.
Works. Happy.

Is this one ----> https://forum.allaboutcircuits.com/...-perhaps-a-similar-helps.202272/#post-1927709

 

In general, the automotive environment is a challenge for delicate electronic systems. The constant vibration at different frequencies and amplitudes, plus the wide temperature variations, can cause connection failures in unexpected places.

 

I repaired an rather cute 1962 RCA Victor 5 tube radio, model X512. It was given to me some time ago in a rather disgusting state. I finally got around to cleaning it up and ordering a couple of 47uF electrolytics to replace the dried out dual 50uF cardboard smoothing capacitor. It worked as soon as I put them in. The radio is AM only and the sound quality is anything but Hi-Fi, but it works the way it was intended, 63 years ago.