757 Labs » Repair

Makita DC1411 Charger / Battery Recharge Problem + Fix

telmnstr — Mon, 04 Jul 2011 16:49:49 +0000

Heads up -- if you have a Makita DC1411 charger for Makita power tools, they might be prone to cold solder joints. Had two NiCad batteries that appeared to be dead. The charger would appear to charge them (LED goes red for a few hours, then switches to green). The batteries would not work.

Bought a generic NiMiHi replacement battery. It came charged, and worked until it was dead. But it wouldn't charge. The charger looked like it was doing it's duties. After some head scratching I took apart the DC1411 charger and noticed the board had a number of areas that looked like the soldering was touched up at the factory. In addition to this, the legs of a transistor (that is on a heatsink) had a broken solder joint. Re-flowed it and the charger is as good as new. Turns out the original batteries still charge! The heatsink apparently gets hot so the bad solder joint is probably due to thermal changes.

Netgear JFS524 switch failure fix (no power)

telmnstr — Fri, 11 Mar 2011 04:52:00 +0000

A friend's church in Norfolk had a network switch failure after a power outage. Here is the quick fix to restore use to the Netgear JFS524 (24 port 10/100 unmanaged) network switches. Symptom was switch would not power on. Standard capacitor issue. There are two on the board, one was visibly swollen and bad. Values were 2200uF at 10 volts (failed cap) and 1000uf at 10 volts (good cap replaced anyway) I think. Check values before you order in case I'm wrong on the voltages, I didn't take notes and it might be 16 volt. As always observe the polarity of the replacement capacitors and referred replacement to someone who is familiar with electronics as it's on the board that has lethal voltages. Power supply board puts out around 3.3 volts at 4 amps or some such. Good luck.

Basic Soldering Class Held on Saturday, March 5 2011

markg — Mon, 07 Mar 2011 16:23:19 +0000

Our first basic soldering class presented this past Saturday was a success -- meaning no fires were started, everybody learned a lot, and no one got burnt...much. Harold did an excellent job of explaining the basics, plus he provided slides and videos illustrating many good and bad examples.

About a dozen attendees were present, with many more showing-up later in the day to participate, even though the actual presentation was over. Items that got "fixed" via soldering included a back-light for a Cruis'n Exotica arcade game and a set of Koss headphones that previously had wire damage due to a mischievous pussycat.

Events for Saturday, March 5, 2011

markg — Tue, 01 Mar 2011 14:36:59 +0000

Here are two events scheduled to be held at the lab on Saturday, March 5, 2011:

2:00 PM EST - basic soldering class by Harold; bring eye protection and something to solder

in Harold's words:

Date: Mon, 28 Feb 2011 19:30:14 -0500
Subject: [757labs] Class this Saturday

I finally decided to dive in and become the experimental pig for the first class! Well at least the first "hardware" related class.

This Saturday, at 2:00 PM, I plan on holding a Basic Soldering Class for anyone who wishes to show up at the Lab. With that said, if for some strange reason we are swamped, I must give preference for room to current Lab Members. That is only fair to them. I doubt we will run out of room, so please show up if you want!

The game plan is to have the herd assembled by 2 PM and the actual start time might be 15 or so minute later. The one thing that would be nice is to have a list of who all plans on showing up so I can have a roster to know when it is time to start. I won't wait all day and plan on letting 2:15 PM being the delayed start time.

For anyone who wishes to attend please bring the following if you have it:

1. Your soldering iron, station, whatever you currently use. PLEASE DO NOT RUN OUT AND BUY SOMETHING!!! Unless you really want to. There are the good bad and ugly types of irons to waste money on.

2. Hand Tools. Most soldering hand tools could be classified as side cutter diagonals or regular diagonals if you don't have those. A straight pick, tweezers, any heat shrinks etc.. Again, don't run out and buy stuff if you don't have it already.

3. Safety glasses. I am not going to demand that anyone wears a pair; however, if you do not wear any type of glasses normally ... I suggest getting a cheap pair. Remember, solder is molten metal. Your eyes do not like it. Burns to your skin are one thing ... burns to your eyes are something you more than likely wont recover from.

4. If you have any type of circuit kits or solder breadboards etc.. that you would like to work on, please bring them. If you don't have anything, please try to snag a cheap one from Radio Shack to play with. Also, if you have some old components like resistors etc.. drag them along so you can have something to solder on.

5. Solder. If you have your own type that you are used to working with bring it. If not, I should have plenty for everyone to play with.

6. Solder wick / Solder sucker. This is something that would be nice to have, but it is not required. We can pass around what we have.

7. If you have a board vise or any other sort of device that you use to hold circuit cards etc.. that would make life easier on you. If not, we will do it old school.

The objective to the course is not to turn everyone into a uber solder dude but to at least give you some insight and hands on experience to allow you to enhance your current skill set. Since I just decided to get stupid and give a class (oh joy!) I don't really have a course written up so please handle the lack of continuity and we will all get through it.

8:00 PM EST - game development meeting by Matt (cyberflux); bring your ideas

in Matt's words:

Date: Mon, 28 Feb 2011 19:20:12 -0500
Subject: [757labs] Game Developers Team (March 5)

I am looking to have a game.dev meeting this Saturday for those interested in creating games at the Lab. Those who are interested feel free to show up sometime around 8pm or so, but I should be there earlier. Currently I am loading services on an older dual Xeon 2 server that will host development environments for Net applications. There is currently no defined hardware for the group so there is flexibility in what platform to go with, however most have been looking at diving into the mobile device market. Any input prior to the gathering is welcomed.

Hope to see some people there! Cheers!

Mata Hari pinball gets a leg up (actually 4)

markg — Sun, 09 Jan 2011 07:33:06 +0000

Ethan, MarkG, and Matt got the legs mounted on the Mata Hari pinball. Later, when DJ Mike arrived, we went to Cogan's Pizza for dinner, where we discussed plans for our upcoming MAGFest road trip. At MAGFest, we plan on setting-up a vendor table to promote the hackerspace, and maybe the radio station project.

There was also talk of a lab members-only meeting the following weekend (Saturday, January 22, 2011 around 6:00 PM EST), followed by an open hack night (8:00 PM EST until whenever).

Other plans include another electronic / MIDI music jam session, and another LAN party, both in February. Stay tuned.

Samsung 226BW / GH22WS LCD monitor fix

telmnstr — Mon, 25 Oct 2010 20:07:46 +0000

Over the weekend George brought by a Samsung LCD monitor that was having issues. The screen backlight would flicker somewhat fast. It looked like the CCFL back light tubes were failing on the monitor, or something was up with the inverter. Upon further inspection it was common bad caps issue. So if you have one of these, you're going to want two 820uF 25V caps and a 330uF 25V cap. You can see the bulging ones inside. C110 and C112 are two of them, the other is in between. I seem to recall similar issues with a different model Samsung that was donated to the lab, perhaps the power supply boards are the same. Faulty components from the manufacturer led to this issue.

Samsung Syncmaster 203B fix

telmnstr — Tue, 24 Aug 2010 19:03:00 +0000

Another dead LCD graciously donated by Mark G, and fixed!

Symptoms: Powers on for a brief second then goes off again. Will not power on.

Fix: A few 820uf caps are bad (normal bad caps issue) as well as possibly a 330uf. Couldn't find them locally, replaced 820uf caps with 1000uf, and replaced the 330uf with one of similar value. Seems to work fine. YMMV.

This is now the labs nicest LCD monitor!

Vizio TV guts

telmnstr — Thu, 01 Jul 2010 00:00:27 +0000

We finally took apart the Vizio 42" EDTV set that came to us for free (but had a cracked LCD.) No luck in finding a replacement panel. The working board set will be sold to hopefully cover some lab costs, meanwhile there are some odd left over parts. There is a trippy diffuser that was used on top of the backlights but before the LCD panel. A cracked LCD panel which serves as a conversation piece, and a backlight with 20 CCFL florescent lights in it.

GV42L is the model.

Travis playing with Vizio backlight diffuser plastic.

Supermicro / Ablecom SP302-1S Power Supply Failures

telmnstr — Wed, 09 Jun 2010 15:58:56 +0000

At my day job we're seeing some failures of Ablecom (Supermicro) SP302-1S power supplies. These SP302 units are used in 1u Supermicro servers. We had one failed one that was out of warranty, I decided to peel it open and see what went wrong.

Not surprisingly, a Teapo capacitor (1000uf @ 10v) was looking pretty bloated. Replacing it with a random pull that was laying around the lab fixed the power supply. More faulty Chinese capacitors. We've seen 4 more of these supplies fail at work, so my guess is all of them are suffering from the same issue. The other failed ones at work are under warranty, but I'm afraid the replacements will have the same faulty components.

Notes: Revision 3.1, Ablecom, SP302-1S used on Supermicro PDSMI+ system boards. Symptoms, units won't power on, LEDs blink faintly, repetitively, indefinitely. With working supply they come on, even with unit powered off.

(Blue electrolytic capacitor on edge of board is the replaced one.)

Ms. Pac-Fail

telmnstr — Sun, 30 May 2010 15:28:51 +0000

I think I'm a okay guy when it comes to electronics knowledge, but I have to admit. The monitor in Ms. Pac-Man is giving me a run for the money. I've replaced the normal common failure parts that are known. Haven't really made much progress. I might just go all out and replace the flyback. The monitor is a Wells-Gardner K7201, so it's a much newer monitor than the original. It looks really good (when working.) There are still some capacitors that haven't been replaced yet, which are next on my to-do list.