Category Archives: How-to

Tipy a triky, jak na to.

JLCPCB Library for Eagle

If you’re looking for JLCPCB parts library for Eagle editor, here it is!

As one of many, I discovered JLCPCB, a manufacturer that produces prototype circuit boards quickly and cheaply. They can also fit SMD components, but here comes the catch: you have to specify a part number for each component. Doing it by hand proved to be a pain in the ass.

That’s why I wrote a program that can extract the data from JLCPCB SMT parts catalogue and insert them into a template Eagle library. Using that app I can quickly update whole library with current part numbers.

The library looks like this:

The project also contains a custom modified ULP script that can export BOM and ULP files with a single click!

Project home is at Github:

Kurzweil PC3K/A – Bad LCD Contrast

Symptoms: When your head is at the optimum position for actually playing or programming the synthesizer, the LCD contrast is not quite right – it is washed out and pale, and the contrast knob on the back of the keyboard does not help – turning that makes the display go from completely white to pale colours but visible text, whereas when viewed from the above it is lush and blue with very nice contrast.

Cause: The problem is caused by wrong value of the SMD resistor R108 (39k) This resistor limits the current to the pot R107 and therefore the contrast range is limited. Continue reading Kurzweil PC3K/A – Bad LCD Contrast

Přestavba FORD TRANSIT z Atmosféry na Turbo

… aneb jak zvednout výkon, snížit spotřebu a zachovat spolehlivost.

Ford Transit 190 2.5D LWB, 1994-2000

Ford Transit Mark 3 se (podle wikipedie) vyráběl v letech 1986-2003.  Hodně  těchto vozů bylo poháněno atmosférickým dieselovým motorem o objemu 2496 cc, jehož sací potrubí připomíná svazek banánů. Ne nadarmo se v Británii používá termín “banana engine”. Tyto motory měly mechanické čerpadlo Bosch, byly velmi spolehlivé, ale strašně líné.

Continue reading Přestavba FORD TRANSIT z Atmosféry na Turbo

Line 6 DT50 – Mains Transformer fail

XFMR Line6As I work in repair center, I could not notice many Line6 DT50 amps with short winding in the power transformer (secondary HV). These transformers are currently out of stock. We decided to manufacture new transformers by ourselves as we can make them better than PRC.

The main cause of this fault is bifilar secondary for 2x258V. These wires conduct high voltage and they are located all the way next to each other. Do not wind up secondary as bifilar.

Mains Transformer LINE6 #11-30-0045 datasheet is located below if you want to make your own. We did not, however, count all the turns of all windings as it was difficult without proper tools. You have to calculate the turns by yourself. Anyway, the datasheet gives you a clue about voltages and color codes.

XFMR Line6 #11-30-0045 Datasheet