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2020-02-21

I found that 100 uH was a good all around value for these solar garden light circuits. But at the time I made these around 2009 the 5252 4 legged chip was uncommon and almost all the garden lights used 2 discrete transistors. I don’t know why they started using the 4 legged 5252 – it would have made more sense to use a 4 pin surface mount chip.

I bought a few dozen 100 uH 10% chokes from an online guy and I measured them at 75 to 80 uH with two different meters. I emailed the guy and I sent them back and he refunded the $$. He also measured them at too low a value with more than one meter, so he had no explanation for the out of tolerance issue. This isn’t the first time I’ve had this problem.

So I gave up on RF chokes for this circuit and started buying the Fair-Rite 594300(something) 3/8 inch or 9mm ferrite toroid cores for 12 cents apiece and winding a 6 inch or so piece of wire on them to make any value of choke that I need. They’re lower resistance so have less I squared R losses than an RF choke – every loss takes away from the brightness of the LEDs. I’m much more satisfied by the results. Every electronics tech or hobbyist should have a few dozen ferrite toroid cores in his parts stock to quickly wind a needed value of inductance. The cores can be from .25 inch or 6mm up to more than 1 inch or 25 mm but larger sizes get expensive. You can get them already wound, of course. A good source for small ones were the CFL lights.

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2020-02-19 Nobility 15 transistor Radio Repair

2020 Feb 18 – Nobility 15 transistors OTL
S/N (?J)29549
I replaced the electrolytic capacitors. The spkr buzzed when I touched the volume control. Nothing from the detector (transistor). It’s unusual. I pulled and tested some IF parts including one of the transistors, no problems found – transistor tested good. I called it a night.

Next day, I tried to inject a low level 455 kHz modulated signal and got nothing. I wasn’t sure if I was getting output from the signal generator so I connected it to the RF input of a signal tracer, nothing. Instead, I connected the AF input of the signal tracer and I hear the modulated RF. That’s backwards! So I checked the signal tracer, detector diode was okay. I’m puzzled. Back to the radio, I probed around some, not getting anything. I probed the transistor next to the variable capacitor and it seemed to not be working. I unsoldered it and tested it and it tested okay. So I soldered it in and the radio worked! I don’t know what I fixed! ?? Weird! I put the radio back together and it’s working fine.

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2020-02-17 I Bid On A Boy’s Radio, Lost

From FB group Vintage Transistor Radios

Last week I bid on a boy’s radio, $26 which lasted up until near the end. But as usual I was outbid at the last minute. I think the demand exceeds the supply, and the prices go up too high. Looks like I’ll be getting one that no one else wants because it’s got a chipped or broken case.

I should try to do a repair of a chipped or broken case with baking soda and crazy glue to see if it can hold up under the normal wear and tear.

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2020-02-14 Zenith Royal 400 S/N Z551549 Replaced Capacitors, Driver Transformer

Zenith Royal 400 s/n Z551549
I soldered broken orange wire to battery holder. Replaced all four electrolytic capacitors. Silent speaker and nothing from earphone jack. I checked the voltage at the collector of the driver transistor, it was zero. One pin of the driver transformer primary measures 5.8 V, the other pin measured 0. Checked, the primary is open. I pulled the transformer out. Yep, open. Why do these primaries go open?
I now have to see if one of the driver transformers I got from the UK will work.

Update Feb 16 – I installed one of the transformers from the UK and it sounds good and loud. But then this Royal 400 has the weird oval speaker that sounds good. So now I can trim the leads and reassemble it. There are chips out of 3 of the 4 corners, and the stick-on label bottom front came off, so it’s not in the best shape. It needs to be aligned to get it performing properly. The case could use cleaning and a polishing.

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LED Indoor Motion Sensing Lights – Decrease On Time

I bought two of these motion sensing LED lights for my hallway. They have a rechargeable cell that is charged through a micro USB port. To see one inside watch big Clive’s YouTube video – the ebay link to buy them is in his description.

The charge lasts for more than a week with frequent use. The light stays in for too long after I walk down the hallway, so I wanted to shorten the delay time. I opened one up and found that it has a common chip, a BISS0001. I searched and found the datasheet for it. The schematic shows the C6 and R10 control the delay time. I found that R10 was connected to pin3, and it read 47k. So I decided to remove it and put in a 10k. The problem was it’s a surface mount resistor. So I got a 10k SMD resistor and a fine tipped iron and some 0.5mm solder. It was a bit tedious, but the result was satisfactory; the light stays on for less than ten seconds. This should extend the battery life for more than a week.

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2020-02-08 60 LED Solar Lights Stopped Working – Dead Diode!

From FB group electronics hobbyists

Over the holidays I installed two solar 60 LED lights I bought on eBay. They stopped working just a few weeks after. I finally got up on the ladder and took them down to see why they died. Well, spit! The solar panel is plugged into the jack on the left, and all of its current went through the teensy diode labeled D2 (see photo). That diode can’t handle a hundred milliamps! So it burned up! I measured 7 volts from the solar panel on one end, and 2.4V battery on the other end – open diode! So I soldered a 1 amp Schottky diode across it. That should handle the current!

Those idiots who designed this must have thought we were all living in Antarctica, where there’s barely any sunshine. They need to be beat over the head with a Clue-by-four! 🤬🤬😠😠

Update – others asked why a Schottky?

Well, since Schottky diodes drop half the voltage, I figured at a certain current it would not get as hot, and waste less power. But the solar panel open circuit was 7 volts, and the battery is a single 16450 lithium cell, so a 1N4002 would work just as well. 👍👍

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2020-02-07 Illegals Contribute Billions In Taxes

SAN DIEGO, CA – JANUARY 26: The Deportation and the separation of families is a major theme in the immigration reform debate. (Photograph by Charles Ommanney/Reportage by Getty Images)
Individuals in the U.S. without documentation are believed to contribute $12 billion to local and state taxes, according to a new study.CHARLES OMMANNEY/GETTY IMAGES

IMMIGRANTS ILLEGALLY IN the U.S. collectively contribute nearly $12 billion each year to state and local tax coffers, according to a new report that challenges recent election cycle rhetoric.

The study from the Institute on Taxation & Economic Policy found that immigrants in the U.S. without legal permission kick in their billions in the form of income, property, sales or excise taxes.

There were roughly 11 million immigrants estimated to be in the U.S. illegally as of 2013, according to the report. And each and every state collects at least a few million dollars from tax payments made by such immigrants each year, ranging from Montana’s $2.2 million to California’s $3.2 billion.

“Regardless of the politically contentious nature of immigration reform, the data show undocumented immigrants greatly contribute to our nation’s economy, not just in labor but also with tax dollars,” Meg Wiehe, the institute’s state tax policy director, said in a statement last week.

Did the Obama Administration Overplay the Plight of Central Americans?

The Pew Research Center recently estimated there were more than 8 million immigrants in the U.S. illegally who were either employed or looking for work in the country in 2012, representing roughly 5 percent of the domestic labor force.

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2020-02-07 Illegals Contribute Billions In Taxes

SAN DIEGO, CA – JANUARY 26: The Deportation and the separation of families is a major theme in the immigration reform debate. (Photograph by Charles Ommanney/Reportage by Getty Images)
Individuals in the U.S. without documentation are believed to contribute $12 billion to local and state taxes, according to a new study.CHARLES OMMANNEY/GETTY IMAGES

IMMIGRANTS ILLEGALLY IN the U.S. collectively contribute nearly $12 billion each year to state and local tax coffers, according to a new report that challenges recent election cycle rhetoric.

The study from the Institute on Taxation & Economic Policy found that immigrants in the U.S. without legal permission kick in their billions in the form of income, property, sales or excise taxes.

There were roughly 11 million immigrants estimated to be in the U.S. illegally as of 2013, according to the report. And each and every state collects at least a few million dollars from tax payments made by such immigrants each year, ranging from Montana’s $2.2 million to California’s $3.2 billion.

“Regardless of the politically contentious nature of immigration reform, the data show undocumented immigrants greatly contribute to our nation’s economy, not just in labor but also with tax dollars,” Meg Wiehe, the institute’s state tax policy director, said in a statement last week.

Did the Obama Administration Overplay the Plight of Central Americans?

The Pew Research Center recently estimated there were more than 8 million immigrants in the U.S. illegally who were either employed or looking for work in the country in 2012, representing roughly 5 percent of the domestic labor force.

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2020-02-06 Royal 500H Alignment

From FB group

This Zenith Royal 500H radio has the extra 8th transistor for the RF amplifier, so it should have excellent sensitivity and be able to pick up those weak stations. Most of the problems with old radios are with the electrolytic capacitors, but the Zeniths all use the carbon composition resistors and they go higher resistance over time. It’s common to have to replace some to get the radio working.

The other thing is the alignment. I recommend you buy (or make out of wood) a nylon screwdriver that will fit the slugs in the IF cans. Then you can gently tune the IFs to peak them. Never use a metal tool, it will crack the ferrite slugs.

You have a better schematic from the Beitman manual. Print it out and keep it inside of the radio.

Take some soft material like plastic or a wooden toothpick and shape the end like a screwdriver blade. I cut one with a knife and rubbed it on the concrete to sand down the tip.

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2020-02-02 IC Logo List

This list seems to be mostly integrated circuits, but some semiconductor makers make discrete devices – transistors and diodes, for example Motorola.

http://www.siliconinvestigations.com/Logos/logos.htm

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