At work we have a KVM over IP switch from Inter-Tech, a KVM IP-KVM101. It is really a small and versatile device that, in combination with 16-port KVM switches, allows us to control a complete rack with test hardware.
The KVM switch provides a web interface with a Java Web Start application for remote access. But the latest browser security updates disabled and removed the Java Web Start support . This move was announced quite some time ago (Oracle White Paper). Still, the vendor of the KVM switch, Inter-Tech, was not able to provide a valuable solution to cope with this problem.
After a bit of Googling I found an Amazon review about this particular KVM switch where the reviewer stated to have installed the firmware from another brand, the LINDY KVM over IP Switch. The LINDY switch looks identical (besides a different sticker) and – even better – their latest firmware provides a VNC server. This would allow us a browser and even operating system independent access to the KVM.
Last weekend I had to replace a 230 V fan (120 mm), a Sunon DP200A, that ‘smelled’ strange and also made strange noises. Better safe than sorry…
Well: I ordered a slightly less powerful Sunon DP201A (at Reichelt Elektronik) to replace the possibly dangerous fan. Although they look similar their connectors are completely different. So I’m now wondering if the first one (the DP200A) wasn’t an original fan at all…?
To make it clear from the beginning: this is a (possibly) destructive method of reading ROM chips. The process of extracting and possibly a resoldering of the memory chip might fail. In my case I’ve tested it on two Sharp CE-150 PCBs I’ve declared to be spare parts. It is only a proof of concept as there are simpler non-destructive ways of ROM extraction on a Sharp PC. I was just curious and so I’m describing my experiences.
Well… At first I did not want to desolder the ROMs: I started with the intention to use a set of probes attached to the individual pins of the chip to read the content of the Sharp PC / CE ROM chips. This did not work due to the narrow leg distance of the QFP chips (0.8 mm).
Desoldering QFP chips can be done rather quickly with a hot air gun. At least that’s the most comfortable way I know of. I usually add some flux and in some cases larger quantities of leaded solder. The latter decreases the melting point and speeds up the process. I don’t care about solder joints as the chips and the pads can easily be cleaned after the removal. Excessive amounts of solder can be removed with flux and a clean soldering iron tip.
This was a little test out of curiosity… I’m currently playing around with an amplifier circuit for the Sharp CE-150 audio output (CMT-OUT) and wanted to see if the signal I’m getting is already distorted when leaving my Sharp PC, or if my circuit and/or sound card is causing the distortions.
The CE-150 uses Frequency Shift Keying (FSK) to transfer binary data via audio signal (e.g. to a tape recorder). It sends four pulses of 1.27 kHz for a binary “0” and eight pulses of 2.54 kHz for a “1”.
To test the circuit I’ve taken the original design and simulated the circuit in LTspice (running under Linux with Wine). This tool allows the simulation of various analog (and digital) circuits – perfect for my test.
The result was – to be honest – pretty surprising for me. The upper screenshot shows the LTspice simulation of the output signal, the lower screenshot was taken from a WAV file in Audacity. I was not only able to simulate the circuit but also to use the resulting signals as a good approximation for my amplifier circuit (not shown). 🙂 One minor fix (also not shown) left was to adapt the transition time between a “0” and a “1” to better fit to the original curve.
In this post I’m describing a method which is widely used to Dump RAM and ROM images on Sharp PC-1500 and PC-1600 systems. This method is non-destructive and can be used on most Sharp PC ROMs and extension cards. It only requires a Sharp CE-150 extension, an audio cable, and a computer with a microphone input (i.e. sound card).
Besides a plotter, the CE-150 Color Graphic Printer also provides two audio interfaces (line-in and microphone output). These were (and still are) used to transfer code or data between Sharp PCs and tape recorders. Today, such recorders are mostly outdated but the method works nonetheless with sound cards. Software tools are freely available (e.g. pocket-tools) that allow the transformation of recorded audio files into binary dumps and even further into BASIC code.
Another day, another dumpster dive, another hit… a digital camera that uses 3.5″ floppy drives as storage device. A Sony Digital Mavica MVC-FD73.
My first surprise was that I was still able to charge the cameras battery. The second surprise was that it was still working flawless. And when doing some background research there was a third surprise that Sony still provides a manual (PDF). I did not expect any of these points.
||640 x 480 (0.4 megapixels)
||CCD (ISO 100)
||10x (focal length ~ 40-400 mm)
|Min shutter speed
|Max shutter speed
|Weight (inc. batteries)
||ca. 500 g
||138 x 103 x 62 mm
From time to time I have (and take) the chance to dumpster dive for electronic parts. Recently, on one of these occasions, an old piece of hardware felt into my hands: a “Moser Galvanosan” galvanic stimulator.
To be honest, I’ve had no idea what it was and at first I only thought it would be a nice case for another project I was working on. After some research (out of curiosity) I thought the device is interesting enough to take some photos of its interior and write about it.
Disclaimer: I’m totally not into alternative medicine or stimulation current therapy. I’m just taking an interesting looking piece of hardware apart, that’s all!
I recently had to revive a (as it at first seemed) dead Li-Ion battery. It was the battery of a newly bought R.O.GNT external speaker which refused to work or even charge. The device was DOA (dead on arrival) but it was so cheap that sending it back would have cost more than I’ve paid for it.
The speaker has an internal Lithium-Ion battery to allow mobile usage. My guess was that this battery slowly discharged while waiting for a buyer and at some point the undervoltage protection kicked in. Normally this protection should prevent a defective cell from being charged. In my case I hoped the cell would still be okay and survive a jump-start. It was successfully done before in other cases. Continue reading
Ugh… this is so disappointing. I tried to solder a ribbon cable to the JTAG header of my “development” FritzBox 7270. Right during the process I accidentally bumped against the bare PCB. It fell off the table and the already soldered cables ripped off some of the pads. Here’s a photo after removing the remaining cables:
I’m unsure how to continue. I followed the traces but so far did not find adequate vias or pads to solder to. At the moment I’m trying to not brick the FritzBox and therefore do not need a JTAG connection… again…
I wanted to make a small tutorial on how to reverse engineer old PCBs, in this case how to trace the vias of a Sharp CE-160 cartridge.
After disassembling I’ve made photos of both sides of the cartridge:
The following step was inspired by an EEVBlog tutorial on reverse engineering a Rigol DS1054Z. The two photos were then aligned (photoshopped) to fit onto each other when printed. One of the two layers needed to be mirrored, and it took a bit to align all vias. Luckily the two photos was taken with a tripod from the same angle. The result was printed onto plastic photocopy foil.
This allows tracing the routes from both sides, including the vias.
In some cases traces were hidden under chips or other parts. I used my multimeter (set to measuring resistance) and needle pin tips to trace them: