Archiv der Kategorie: repairs

… speaks for itself

USB stick defective?

 

Again and again it happens to me that a USB memory stick loses its function and is suddenly no longer recognized. Often the stick is still registered as a drive in the system, but it lacks the disk, or even the system reports that the stick is not formatted. And even though he just recently, full of important data, has worked in another computer. 🙂 (Here would now be the story with the backups or backup copies …). All these problems are mostly due to operator errors or mechanical problems. For example, an operator error may be that the stick is being pulled while one more writing is in progress. The stick is then de-energized during a process. And depending on whether the controller or flash memory can handle it, the stick will survive or not. Often, mechanical defects are the cause of breakdowns. So it may be that the solder joints between the connector and the board break, or get the connecting pins of the quartz or oscillators contact problems.

In this case, I got a miniature stick from extrememory, which does not want to give away its stored data. It is displayed in the system administration, but if you want to access it, the message „no data carrier found“ comes. The attempt to format or partition over diskpart from the commandline did not work. Also various tools like „SDFormatter“ or „USBstick_Formattool“ failed. Even with Linux or on MAC systems, no success was achieved. So a stick for the barrel … But I thought, even if the stick in its small design rather not close to a mechanical defect – why not take a look anyway 🙂 And at 16GB I will not give up so fast.

So I tried to gently open the case by first removing the metal case of the USB connector.

That works quite well. After I wanted to take a closer look at the appearing small printed circuit board with its tracks, there suddenly appeared something familiar.

That looks like an SD card. More specifically, like a microSD card.

That’s the way it was. The USB stick is nothing more than a MicroSD card reader, in which such a card is installed. Using tweezers, the SD card could be levered out.

Apparently here again the problem is with the contacts, or contact springs between card and card reader. It is the cause of the problem, because the SD card worked fine in another card reader and all the data was available. It pays to invest in front of the garbage bin for a few minutes and to inspect the innards of the device.

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DAT-Walkman Sony TCD-D3

Sony TCD-D3

At least one blog post per month to write I have set myself the goal, even if it is not always easy to implement this temporally. Anyone who has small children himself can perhaps imagine that. But in the evening and in between, I can collect material and edit it. -> it just takes everything much longer. This time I organized a Sony DAT recorder for retro audio. It is a Sony TCD-D3 from 1990-91, a so-called DAT Walkman.

DAT (Digital Audio Tape) is an audio magnetic tape recorded digitally. The recording format and the sound quality are essentially similar to those of the audio CD. The recording takes place on small cassettes, which were also used in the storage area in the EDP (DDS tapes). The DAT format was intended as the successor of the audio cassette, could not prevail in the broad market. It is also discussed here that the music industry did not want to see the format in the consumer world, as it was possible with the system to produce digital, lossless copies.

The technical structure of the cassette drive corresponds to that of a video recorder. The tape is pulled out of the cassette with loading arms and passed around a rotating head (DAT-R). The recording is done in helical scan. The copy, which I acquired this time as „defective“, was with the defect: Cassette shaft does not open, described. After dismantling, I noticed that I was not the first to look at the inside of the device after the factory. Someone was already messing around. All (tantalum) capacitors were soldered, the lead wires to the battery pole contacts were „pinched off“ and the wires were missing. The Flexiprint, which connects the front panel to the mainboard, had a broken track when looked at closely.

fixed trace

The broken wire could be repaired by carefully scraping off the insulation and brazing a stranded wire. The capacitors I have all newly soldered and of course checked before. Here I noticed that some were not soldered properly and had a cold loosening at a pole or were not connected to the pad. The battery contacts were also provided with new wires. On the mainboard there is also a DC / DC converter, which makes the supply voltages for the logic and the audio components from the 9V input voltage. (5V +/- 7V). This converter is housed in a completely soldered tinplate box. Of course, nobody was inside and checked the Elkos inside. That was done quite quickly and the small box was overtaken. Now I was able to provisionally reassemble the boards and drive and put them into operation. As data carrier I used a DDS (storage) cassette. So tension on it and „Eject“ pressed and lo and behold, the cassette compartment opens immediately. From my Handyaudioplayer as a music source, I made a trial recording. And what can I say, a wonderful sound quality!

The next issue to fix is ​​more of a visual nature. These are the side casings, which are coated with a rubber coating and this begins to seem to change chemically and becomes sticky. So I washed this gum carefully with isopropanol and tried not to replace the white printed lettering with. That worked quite well. With acrylic clearcoat I then painted the parts.

painted side casings

After curing the clearcoat I was able to assemble everything again and start the final test. The following pictures show the inside of the TCD-D3.

Specifications of the TCD-D3

  • Type: Digital Audio Tape Dec
  • Audiotracks : 2-channel stereo
  • Tape speed: 4.075, 8.15 mm/s
  • recording time: 240 minutes
  • headsystem: 2000rpm, rotary
  • D/A converter: 16 bit linear
  • A/D converter: 16 bit linear
  • Samplefrequency: 32-48kHz
  • Frequency Response: 20Hz to 22kHz
  • Signal to Noise Ratio: 90dB
  • Dynamic Range: 90dB
  • Total Harmonic Distortion: 0.0008%
  • Analoginput: 80mV (line), 0.25mV (mic)
  • Analogoutput: 0.5V (line)
  • Dimensions: 85.2 x 40 x 120.1mm
  • Weight: 0.42kg

 

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The old repair shop

While browsing the digital archives, I noticed the following pictures again.
Meanwhile, more than ten years have passed since I had to initiate the end of the television repair shop.

Look in the old workshop

Almost at the same time as the widespread use of flat screen televisions, orders were down. Except for a few customers, who insisted on retaining the old technology from ideational values, hardly anyone could fix it. Due to wage side costs and realistic, minimal profit-oriented pricing, it was just too expensive for people. If, for example, a repair of the high-voltage power supply of a television (replacement of line transformer, driver transisor and various capacitors and resistors) a price of about 90 euros assumed, that was again borderline, almost too expensive. If one considers that for these sum the parts scarcely 40 euro in the EK cost, then for the remaining 50 euro the error had to be searched for and found, everything to be expanded and reinstalled.

The unit had to be cleaned inside (often we got „boxes that collected the dust and nicotine of twenty years“.) Also, a careful test run should be done, so what about the 50 bugs? Hired labor costs more than half of non-wage labor costs. How many devices do you have to repair during the day in order to cover your costs?
 
 
dust accumulation

Sometimes you could see curiosities. Since one or the other owner of the TV has ever tried even as a repairer and found a faulty network backup. – „No problem, is only a backup …“ Which is then wrapped in the absence of a suitable new backup and knowledge simply with cigarette paper …

 
 
 
 
 
 
 
„expert“ repair of the customer
 
„Then it works again …“ which turns out to be not quite correct. After inserting „it pops and flashes“ and nothing was more … So the device came to me on the desk … „Why is the repair so expensive? – was only a fuse broken – I know myself out there – I am an electrician „You can hear such sayings then.
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