Tech Forum

Danger Danger! The typical lamp dimmer is not compatible with the typical cheap fan motor. There are good articles on the web as to why. Look up shaded pole speed control and see why. That said, I find that box fan motors tend to be OK with better (triac based) motor speed controllers, such as sold by Harbor Freight and on eBay. On a shaded pole motor of a typical cheap fan, overheating the motor is possible.

Just connect the new dimmer to the High contact of the switch.

Please do not even think of using a simple lamp dimmer for this!

Lamp dimmers are for incandescent (filament) bulbs only, not inductive motor (AC or DC) loads and will likely cause a fire! A lamp dimmer connected to a ceiling fan caused such a fire, nearly burning my neighbor’s house down! Don’t do it.
The easiest, cheapest and safest solution is readily available from Harbor Freight Tools. Item 43060 is a “Router Speed Control” and works great with inductive AC or DC motors up to 15 Amps (120VAC). I have several and use them to vary the speed of many tools, not just my router. Costing about $15 a piece, I use this controller with my 5-speed wood drill press (when drilling soft metals that require slower speeds); with Harbor Freight’s largest “hurricane” fan (which also has a HI/MED/LOW/OFF switch); and other AC powered fixed speed tools.

Equipped with a 15 Amp 3AG type fuse and a 3-prong receptacle, this lightweight controller is hard to beat and much safer to use.

Good news and bad news: A light dimmer will in fact slow down a fan motor. However, the motor will make a horrible buzz. Look for a device called a Quiet Fan Speed Control. This is just a tapped inductor with a switch to cut in more or less of the coil. You can tell you have one if the speed control is a switch rather than a pot. Given the multiple speed taps plus the original high-medium-low, you should find a speed that suits.

It should work just fine. Wire it to the high winding. I did this myself to a box fan 43 years ago and it is still running.

Theory: It makes a ticking sound that sounds like a dying fish which attracts other fish.

You might try: https://www.electronickits.com/electronic-fish-caller-plan/ On the other hand if all it does is tick, you now know what the circuit is supposed to do and you might be able to complete it with just that much information. The above link sells plans to build such a thing. There are others selling kits as well. I simply did a web search to find the above.

I built one years ago. It was designed to produce a high frequency noise that supposedly attracted fish. Maybe my fish were hard of hearing but it never worked in my field trials. I have never seen them promoted in any fishing supply catalogs either.

Seriously, you can find all the circuits you want by Googling "Fish Caller Circuit" and looking at the images. Less than seriously, it emits Fishy Language for "Neener neener neener! You can't catch me!"

There are circuits to control a toaster oven to make a reflow oven, but I get decent results using a normal toaster oven and the following procedure:

1. Mark the top of the toaster oven with a sharpie that it is never to be used for food.
2. Use standard Tin-Lead solder paste, with a low melting point.
3. Get a stencil to help screen the paste on your board - OSH stencils work fine for most hobbyist work (low volume).
4. Once you have placed the components, put your board in the toaster oven, and turn it on to bake at a low temp (~250) and leave for 5-10 mins to bake out any moisture.
5. Turn the toaster up to broil, and keep an eye on the board - you will be able to see when the solder melts and begins to flow - I usually wait 20-30 seconds after I see the solder begining to flow, then turn off the toaster oven.
6. Open the door and allow the board to cool for 5-10 mins before moving it, then take it out of the oven and let if finish cooling on your bench.

I am this very moment seeking the same solution you are for a variety of surface-mount (SMD) projects. I also have a cheap unused toaster oven just waiting to heat things up!

Two temperature control approaches are readily available, with one being more complicated with PIC processor and other components. I am “Old School” and not yet experienced with programming these, but I located a nifty Nuts & Volts article about a toaster oven controller. This article appeared in NV’s June 2008 issue, authored by Kit Ryan, entitled “Oven Flow 1.0.” I just printed the article out after hunting through my .pdf collection of NV. You should give this a read because K. Ryan covers the essentials of reflow soldering SMD devices. Important for success is knowing and maintaining the proper Time vs. Temperature profile. The temp ramps up, levels off and then ramps down all under processor control. Kit also refers to SparkFun’s Electronics Reflow Toaster Controller for toaster ovens!! Another reference is to Kester’s SMD soldering time/temp profile (kester.com) and I plan to read it: you should too.

The 2nd least complicated method is analog and manual. Should you mount a readily available barbeque thermometer inside your toaster, you’ll be able raise/lower inside heat and time the temperature transitions with a watch. I understand this not-very-fancy-at-all method and notice my grill’s temp gauge reads up to 700 degrees F. That’s more than enough range to see SMD solder paste melt. My grill’s gauge is a replacement I bought in the BBQ section of a local big box store and is not expensive. Now all I need is patience and a working clock!

Toaster ovens are used for surface mount soldering. Usually there is a temperature profile that is used. Sparkfun Electronics made a kit that you could use to control a toaster oven but they don’t sell it anymore. You could probably find the temperature profile on the net and do it manually. You can also use a heat gun to solder surface mount devices by putting solder paste/solder flux on the pads and then heating up the board with the heat gun. I have found this to not be reliable, especially if there are other parts already soldered on the board.

Another way to do it is manually. If the PCB was tinned when it was produced, it is possible to tack down a few key pins on the board and then solder the rest. This requires a very fine tipped soldering iron, very small diameter solder, and a lot of patience, but it has worked for me.

A few other notes. Getting the solder paste/flux onto the board without bridging adjacent pins is tricky. Often times, a stencil mask can be made when the board is produced. They make it easier to get the solder paste /flux down accurately. However, they come in various quality levels with the good ones being higher priced.

For one-sided boards, electric skillets are known to work. You also need a pair of tongs to get the board in and out quickly. If you simply turn the skillet on and wait for it to heat, the flux will burn off before the solder melts. Unfortunately, I presently have a workbench full of boards with components on both sides. For me, it's back to the soldering iron.

Yes, the iPod requires a higher current to charge and so a simple 200 mA 5V USB brick won’t work. The higher bricks are usually modified to indicate to the plugged in device that higher current is available.

You can actually build the circuit that gives the right voltage level on the data pins to indicate this capability, but an easier “fix” is to simply modify a USB extension cord by opening it up & shorting the two data lines the iPod “sees” together. I’ve made a number of these & use them for a number of reasons.

1. I can plug it into ANY computer & charge the iPod without it trying to sync.
2. I can use non-standard iPod chargers to charge my iPod, as long as they are 500 mA or above.

You can also look up the difference between a low and higher powered USB charger on the Internet to see the specifications and schematic. Or at least when I did that years ago I found what I was looking for & found my “fix” was much easier to implement.

In order for the IPOD to charge using any USB charger you need to use a small adapter.

Apparently Apple chargers have a resistor between the 2 data pins inside the charger. I had a similar issue when trying to use a non Motorola or car charger with the Razor V3M phone. A small adapter does the trick and makes the device think a genuine charger is connected.

You can get one here:
www.boxwave.com/apple-ipod-nano-3-travel-chargers/apple-ipod-nano-3-ipod-charging-adapter/bwpdd/fpz-gcgz/
They run about $8 or so.

You will need to add a few resistors. Google “iPhone charger circuit.” You should find several discussions about this. For example, see www.epanorama.net/newepa/2010/08/18/apple-charger-secrets/

There is no reason for it not to charge unless the iPod charging port is damaged. Both a phone and iPod should have similar charging requirements.

In order for the iPod to charge using any USB charger you need to use a small adapter.

Apparently Apple chargers have a resistor between the 2 data pins inside the charger. I had a similar issue when trying to use a non Motorola or car charger with the Razor V3M phone. A small adapter does the trick and makes the device think a genuine charger is connected.

You can get one here: www.boxwave.com/apple-ipod-nano-3-travel-chargers/apple-ipod-nano-3-ipod-charging-adapter/bwpdd/fpz-gcgz/

They run about $8 or so.

iPods require voltages on the data pins of the device in order to charge. If your charger has just the positive and negative pins connected to the plug, your iPod won’t charge. This is probably the case. Search the net for USB charger circuits.

The modification will require four resistors wired from ground (negative) to positive as voltage dividers. One pair for Data + and the other pair for Data -. According to the circuit diagram I found you will need two 27K resistors, a 22K, and a 39K. The two 27K resistors are wired to ground (negative) pin 4 on the charger plug. The 22K and 39K are wired to the positive pin 1 on the charger plug. The junction of the 27K and 39K divider is wired to pin 2 (Data -) on the charger plug. The junction of the 27K and 22K divider is wired to pin 3 (Data+) on the charger plug.

Also, for an iPod you should have a charger capable of at least 2 amps output. The wimpy 1 amp chargers will take a much longer time to charge apple devices like an iPod. To be sure which pins are which, just do a search for USB pinouts.

No! This is wrong!! The isolation transformer powering the monitor in an arcade game is there because the older monitors use a "hot chassis" design meaning that they contain no internal isolation from the AC line. The ground that the signal input is referenced to is not ground at all without an isolation transformer! Connecting a monitor to the logic board in the game without isolation is going to result in a flash and bang that usually causes serious destruction to both the monitor and the logic board. It is not there to protect the player from electric shock as the published reply states. All exposed metal parts must be bonded to the ground wire in the power cord for that.

Arcade monitor isolation transformers are readily available and inexpensive. I hope this answer reaches the person who originally asked before they take the advice that was printed. Note that some newer monitors do have built in isolation but unless this is known with certainty *do not* attempt to bypass the transformer.

I'm worried that the monitor discharging advice given here could potentially kill someone. While the alligator clip/long screwdriver method is sound, touching the corners of the CRT is not. To discharge the monitor the screwdriver has to be inserted under the anode cap. Just touching the CRT or frame will not discharge the monitor, and could result in 20,000-30,000V being discharged through the tech. CRTs contain very high voltages. Please make sure you know what you are doing before attempting to service one.

I read the published answer to this in N&V, and the arcade preservationist in me cringed a bit. If the cabinet had an isolation transformer, in the bottom, you definitely want to run it with one. The transformer is actually there for the monitor, not the game PCB. The older CRT monitors used in arcade games don't have an internal isolation transformer on the chassis, unlike newer CRTs with an internal switching power supply that do. Running without an isolation transformer will most likely result in a dead monitor. Most arcade monitors run without an isolation transformer will end up blowing their Horizontal Output Transistor (HOT).

The transformer, if it really is a 1:1 isolation transformer, is probably for your protection not the user’s protection. Second it may also be to insure that it doesn’t matter how the plug (I’m assuming it is non-polarized) is plugged into the wall.

On the other hand if this is an older unit with a picture tube the transformer might be the horizontal flyback transformer that generates anything from 10,000 to 30,000 volts to be placed onto the picture tube. However, a flyback does not look like an isolation transformer, so I have to assume it is not one of those and that you know the difference.

Thus we’re back to my first two possibilities, it is for service safety and using a non-polarized plug - again service safety. Just be sure to unplug the power cord, then discharge the picture tube, wait about 15 - 20 seconds and discharge the picture tube again, repeat until no spark is generated. The old standard way to do this is to use an alligator jumper from ground to a big/long screwdriver with an insulated handle & bring it close to some part of the picture tube, then do it again to a different part of the tube. The picture tube has four corners so I would go round & round till no more spark jumped.

The isolation transformer is for protecting the MAIN METAL PARTS of the arcade machine from electric shock - specifically the coin-handling mechanism. If you’re not going to use the coin machinery (i.e., replace it with a switch or similar), then you could probably get away with not using the line isolation transformer. HOWEVER, consider integrating EMI/RFI/surge protection on the AC power input to help the machine live a little bit longer.