When his 6 years old induction cooker recently broke, [Johannes] decided to open it in an attempt to give it another life. Not only did he succeed, but he also added Bluetooth connectivity to the cooker. The repair part was actually pretty straight forward, as in most cases the IGBTs and rectifiers are the first components to break due to stress imposed on them. Following advice from a Swedish forum, [Johannes] just had to measure the resistance of these components to discover that the broken ones were behaving like open circuits.
He then started to reverse engineer the boards present in the cooker, more particularly the link between the ‘keyboards’ and the main microcontroller (an ATMEGA32L) in charge of commanding the power boards. With a Bus Pirate, [Johannes] had a look at the UART protocol that was used but it seems it was a bit too complex. He then opted for an IOIO and a few transistors to emulate key presses, allowing him to use his phone to control the cooker (via USB or BT). While he was at it, he even added a temperature sensor.
Over the last few years, [Tobias] has repaired a number of USB Flash drives. This strikes us as a little odd, given small capacity Flash drives are effectively free in the form of conference handouts and swag, but we’re guessing [Tobias] has had a few too many friends lose their thesis to a broken Flash drive.
In all his repairs, [Tobias] found one thing in common The crystal responsible for communicating with the USB controller is always broken. In a way, this makes a lot of sense; everything else on a Flash drive is silicon encased in an epoxy package, where the crystal is a somewhat fragile piece of quartz. Breaking even a small part of this crystal will drastically change the frequency it resonates at making the USB controller throw a fit.
[Tobias]‘ solution for all his Flash drive repairs is to desolder and change out the crystal, bringing the drive back to life. Some of the USB Flash drives even have multiple pads for different crystal packages, making it easy to kludge together a solution should you need to repair a Flash drive five minutes ago.
It’s a wonderful thing to see a clever hack repair instead of disposing of a product. The best repair approach is finding exact replacement components, but sometimes exact components can’t be sourced or cross-referenced. Other times the product isn’t worth the shipping cost for replacement parts or you just don’t have time to wait for parts. That’s when you need to really know how something works electronically so you can source suitable replacement components from your junk bin to complete the repair. This is exactly what [Daniel Jose Viana] did when his 110 volt Dremel tool popped its TRIAC after he plugged it into a 220 volt outlet.
[Daniel] knew how the TRIAC functioned in the circuit and also knew that a standard TRIAC of sufficient specifications could be used as a replacement even if it didn’t have the correct form factor to fit the PCB layout. For [Daniel’s] tool repair he had to think outside the box enough to realize he could use some jumper wires and snuggle a larger TIC206E TRIAC that wasn’t meant for the device but still applicable into the housing where there was enough free space. A little shrink-wrap and all was good again. Sure the fix was simple, but let’s not trivialize the knowledge he needed for this repair.
And if you’re wondering if it worked, he notes that he’s been using this tool for three years since the repair. We thank [Daniel] for sharing this tip and allowing us to add this to our tool belt of Dremel repair tricks.
Something’s fishy about the above-pictured ultrabook: it’s an Asus Zenbook that [WarriorRocker] hacked to use a MagSafe power connector typically found on Macbooks. Most of us probably consider it standard procedure to poke around inside our desktop’s tower, but it takes some guts to radically alter such a shiny new ultrabook. It seems, however, that the Zenbook’s tiny power plug causes serious frustrations, and [WarriorRocker] was tired of dealing with them.
Using information he found from an article we featured earlier this summer on a MagSafe teardown, [WarriorRocker] hit up the parts drawer for some connectors and got to work. He had to modify the MagSafe’s housing to fit his Zenbook while still holding on to the magnets, but he managed to avoid modifying the ultrabook’s case—the connector is approximately the same size as a USB port. Deciding he could live with just one USB connection, [WarriorRocker] took to the board with a pair of side cutters and neatly carved out space for the MagSafe next to the audio jack. He then soldered it in place and ran wires from the VCC and Ground pins along a the channel where the WiFi antenna is routed, connecting them to the original power jack’s input pins.
[WarriorRocker] regrets that he fell short of his original goal of getting the MagSafe’s protocol working: he instead had to hack on his own adapter. We’re still rather impressed with how well his hack turned out, and it did manage to solve the charging problems. Hit us up in the comments if you can provide some insight into the MagSafe’s otherwise obscure innerworkings.
[borgartank] is starting a hackerspace with a few guys, and being the resident electronics guru, the task of setting up a half-decent electronics lab fell on his shoulders. They already have a few soldering stations, but [borgar] is addicted to the awesome vacuum desolderers he has at his job. Luckily, [bogar]‘s employer is keen to donate one of these vacuum desolderers, a very old model that has been sitting in a junk pile since before he arrived. The pump was shot, but no matter; it’s nothing a few modifications can’t fix.
The vacuum pump in the old desoldering station was completely broken, and word around the workplace is the old unit didn’t work quite well when it was new. After finding a 350 Watt vacuum pump – again, in the company junk pile – [bogar] hooked it up to the old soldering station. Everything worked like a charm.
After bolting the new and outrageously large pump to the back of the desoldering station, [bogar] wired up a relay to turn on the pump with the station’s 24V line. Everything worked as planned, netting the new hackerspace a 18 kg soldering station.
Designing and building something from scratch is one thing. But repairing fried electronics is a much different type of dark art. This video from [Mike's Electric Stuff] is from more than a year ago, but we didn’t think you’d mind since what he accomplishes in it is so impressive. He’s got a burnt out pick and place hybrid power module which isn’t going to fix itself.
The power module construction includes a part that has chip-on-board-style MOSFETs and the circuitry that goes with them enclosed in a black plastic housing. It’s kind of like a submodule was encapsulated using the same plastic as integrated circuits. After cracking it open it appears the bonding wire has burnt away. [Mike] connects a jumper wire to one of the board traces in order to use an external MOSFET. This is much easier said than done since the module substrate is ceramic designed to dissipate heat. We’re amused by his technique of melting the jumper into the plastic housing to protect it from the heat sink that goes over the package. In the end he gets his CNC running again. This may not be the best long-term fix but he just needed to continue running until a proper replacement part arrives.
Oh, one more thing: the Metcal vacuum desolderer he uses in the video… do want!
Continue reading “Tricky Repair of Power Driver for CNC Machine”
[Alan Wolke] aka [w2aew] was challenged to repair a friends Yaesu FT-7800 ham radio. This radio operates on two ham bands, 2 m VHF and 70 cm UHF. The complaint was that the 2 m side was not working but the 70 cm was transmitting fine. Alan started by verifying the complaint using a Bird watt meter with a 50 watt slug and terminating the signal into a 50 W dummy load. [Allen’s] bird meter is the type that has an RF sampler that can be connected to an oscilloscope for added signal viewing and validation.
After verifying that the radio was not working as described, Alan starts by glancing over the circuit board to look for any obvious damage. He then walks us through a block diagram as well as a circuit diagram of the FT-7800 radio before stepping us through the troubleshooting and diagnostics of radio repair. Even when he realizes he might have found the problem he still steps us through the remainder of his diagnostics. The skills and knowledge that Alan shares is extremely valuable to anybody looking to repair radios.
Spoiler alert. At the end of the first video he determines that the pin diodes near the final VHF output were bad. In the second video he reveals that he could no longer source these bad components. Through some clever evaluation of a more current Yaesu radio, [Allen] was able to find suitable replacement components. Lesson two ends with some surface mount solder rework tips as well as testing that the repair was successful.
And just in case you don’t know what a pin diode is, or is used for, Alan shares a third video covering just what this component is and does in a radio. You can follow the jump to watch all three videos.
Continue reading “Diagnose and Repair a Yaesu FT-7800 Ham Radio”