Repairing A VFD Driver On A Car Stereo

September 24, 2012 by Mike Szczys 29 Comments

We love seeing repairs and always marvel at the ability to track down the problem. [Todd] seems to have a knack for this. He was met with a lot of adversity when trying to get the Vacuum Fluorescent Display working on his car stereo. A lot of persistence, and a little bit of taking the easier way out let him accomplish his goal.

The head unit is out of his 1994 Jeep. He knew the radio functionality still worked, but the display was completely dark. After getting it out of the dashboard he connected it to a bench supply and started probing around. He established that the data lines were still working by setting the radio to auto scan mode and testing with a multimeter. When he went to measure the cathode pins he didn’t get any reading. It seems the driver which supplies that signal is burnt out.

One easy fix would be to replace the parts from a scavenged unit. [Todd] hit the junkyard and picked up one from a Jeep that was just one model year apart from his. Alas, they weren’t exactly the same, and although he swapped out a chip (using a neat heated solder sucker) it didn’t work. In the end he simply dropped in a power resistor to use the 12V rail as a 1V at 0.1A source for the filament.

You can see his repair extravaganza in the video after the break. If you’re looking for tips on scavenging these types of displays check out this post.

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How To Repair A Ribbon Cable Connection On Consumer Electronics

September 20, 2012 by Mike Szczys 34 Comments

It’s not uncommon in cheaper devices to find a ribbon cable soldered directly to the circuit board like the one pictured above. Using a connector would have been a much more resilient approach, but adding parts adds cost. If you take a close look you’ll see things aren’t looking so great anymore. [Chaotic and Random] pulled this board out of his VW Camper Van. Rather than buy an expensive replacement part, he shows us how to repair a soldered ribbon wire connection.

This repair is rather invasive and he suggests trying some hot-air rework (possibly using a heat gun) to fix up any misbehaving connections. But if that has failed it’s time for the knife. The first step is to cut the ribbon so that the LCD can be removed from the board. From there he peels the remaining scrap off ribbon of the pads. This makes us cringe as it could lift traces from the PCB, but he was gentle enough to avoid it. Now comes the time to start reassembling. After thoroughly cleaning the pads the ribbon is cut straight and resoldered. The trick is to flow the solder without melting the ribbon. He uses tin foil to cover the tip and cools it on a moist sponge just before reflowing solder.

It sounds like more art than science. But when the only alternative is to spend hundreds on a new part it may be worth a try.

[Quinn] Resurrects An Amplifier That Experienced Death-by-capacitor

September 12, 2012 by Mike Szczys 28 Comments

[Quinn Dunki] is adding wireless audio to all of the rooms in her home. She’s going with Airplay, snatching up used or refurbished Airport Express units because of their ability to work with both her existing WiFi and the Airplay protocol. The last piece in the puzzle is to get an Amp and she chose the small unit seen above. The problem is that it was dead on arrival and she couldn’t get the company to respond to her issue. So she cracked it open and fixed it right up.

The offenders are the three electrolytic capacitors at the top of the picture. She took some close-up images of each and you can’t miss the fact that they’re blown out. These are often among the higher price-per-unit parts and manufactures try to pinch the penny as much as possible. Add to it the heat in a small enclosure like this one and you’ve got a failure. [Quinn] dug through her junk bin but the size of the replacement had to be a perfect match so she ended up putting in a parts order. The new caps fit and work perfectly as you can hear in the clip after the break.

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Send Your Nexus 7 Back… To Tighten One Screw?

August 10, 2012 by Mike Szczys 12 Comments

It seems that some of the Nexus 7 models have an assembly issue that makes the bezel uneven with the screen. It’s just in one spot but your shiny new toy shouldn’t have this kind of problem. Of course it comes as no surprise that Google wants you to send it back for service. What is a surprise is that the fix involves tightening just one screw. Now we can’t stand for shipping something round trip when it comes to this low-skill fix. Luckily neither can [Baddspella]. He shows us just how easy it is to repair the Nexus 7 yourself.

The only tools you need are a guitar pick (or other thin plastic prying device) and a very small Phillips screwdriver. Starting at the top of the tablet he uses the plastic pick to pry off the back of the case. This exposes the screws which hold the bezel in place. Find the loose one, and give the screwdriver a turn. Now just snap the back cover in place and you’re done. We’ve embedded the video after the break for your convenience.

It’s super simple…. so don’t be afraid to crack that thing open.

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Reworking The Electronics For Better Computer Speaker Audio

July 31, 2012 by Mike Szczys 23 Comments

[Michael Chen] liked the sound he was getting out of these Corsair SP2200 computer speakers, with one big exception. They were giving off some unpleasant crackling sounds. He figured this might be as easy as replacing a faulty potentiometer, but soon found out the fix was going to be more complicated than that. All said and done he ended up reworking the design of the speakers’ amplifier board.

The hardest part was identifying the problem. Once he had cracked open the case he found the volume potentiometer was working correctly by testing it with a multimeter. Next he inspected the board for bad solder joints but didn’t really find any. The breakthrough came when he realized that the crackling was also happening when he used headphones. With that discovery he started making a few more observations and realized that the crackling didn’t happen when the volume knob was all the way up or all the way down. There was an impedance issue between that potentiometer and the amplifier circuit. He rerouted the signal flow on the board to use the headphone amp as a filter and it fixed the problem. Fittingly, he’s entered this project into the Instructables Fix & Improve contest.

Recovering From A Seagate HDD Firmware Bug

July 30, 2012 by Mike Szczys 41 Comments

Hard drive firmware is about the last place you want to find a bug. But that turned out to be the problem with [BBfoto’s] Seagate HDD which he was using in a RAID array. It stopped working completely, and he later found out the firmware has a bug that makes the drive think it’s permanently in a busy state. There’s a firmware upgrade available, but you have to apply it before the problem shows its face, otherwise you’re out of luck. Some searching led him to a hardware fix for the problem.

[Brad Garcia] put together the tutorial which illustrates the steps needed to unbrick the 7200.11 hard drive with the busy state bug. The image in the lower right shows the drive with a piece of paper between the PCB and the connectors which control the head. This is necessary to boot the drive without it hanging due to the bug. From there he issues serial commands to put it into Access Level 2, then removes the cardboard for the rest of the fix.

In the tutorial [Brad] uses a serial-TTL converter. [BBfoto] grabbed an Arduino instead, using it as a USB-ttl bridge.

Make Your Own Custom IPhone Back Glass

July 26, 2012 by Mike Szczys 18 Comments

[Jake von Slatt] is at it again; putting his own artistic spin on ordinary items. This time around it’s the glass on the back of an iPhone. It kept breaking and after a few replacements he wanted to try to replace the glass with a piece of etched brass. But part way through that experiment, he figured out how to use toner transfer to develop these stunning custom iPhone glass back plates.

The first step is to source the correct replacement back for your phone. These are made of two parts, the glass and a plastic backer. By carefully heating and wedging the two parts with some popsicle sticks he was able to separate the pieces. Next, he cleans and buffs the glass, preparing it for the artwork he is about to apply. Toner transfer paper, just like that used for PCB resist, is used to print and adhere a design to the underside of the glass. From there he hand paints over the black outline to achieve the results seen above.

It takes time and patience, but shouldn’t be any harder than etching a circuit board.