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  1. bertus

    Random digital potentiometer driving

    Hello, The 557 must be a typo. I know the 555 Single timer, 556 dual timer, 565 PLL and 567 tone decoder. What digital potmeter do you intend to use? How is the pot controlled? I know versions that use SPI, that must use a microcontroller to set it. I also know versions that has up/down and...
  2. bertus

    xerox 8850/510 power supply defect

    Hello, Did you know that XEROX has its own support forum? https://forum.support.xerox.com/ Perhaps the manual gives you more info: https://www.scribd.com/doc/230411151/8850-510DP-Service-Manual-pdf Bertus
  3. bertus

    xerox 8850/510 power supply defect

    Hello, You can NOT replace the LM7372 with a LM741. The LM7372 is a high power, high speed, dual opamp. The LM741 is a single, slow speed opamp. https://www.digikey.com/en/products/detail/texas-instruments/LM7372MR/3701242 Bertus
  4. bertus

    Cannot find this specific resistor, help!

    Hello, Here is a reduced color version of the picture. Bertus
  5. bertus

    3 jumper pinouts on R3 Arduino Uno

    Hello, You must have a clone, as the origenal does not show the jumpers: Can you show your version? Bertus
  6. bertus

    TFT Screen problem (Toshiba TECRA 730CDT)

    Hello, Is the first picture from the BIOS? It shows VGA compatible (640X480). Are there other settings like SVGA (800X600) and XGA (1024X768)? https://en.wikipedia.org/wiki/Video_Graphics_Array Bertus
  7. bertus

    TFT Screen problem (Toshiba TECRA 730CDT)

    Hello, As @kellys_eye said, check the resolution and refresh rate: The screen seems to be 1024X768 @ 60 Hz: https://www.panelook.com/LQ12DX03D_Sharp_12.1_LCM_overview_9920.html Do you have the maintenance manual? TECRA 730CDT maintenance manual Bertus
  8. bertus

    Book Reviews

    Hello, Here is a collection of the folkscanomy electronics: https://archive.org/details/folkscanomy_electronics?and%5B%5D=languageSorter%3A%22English%22&sort=-publicdate Bertus
  9. bertus

    Problem with Ramp signal Generator using IC 555

    Hello, Why not use a couple of diodes for R1 and make Re smaller? http://www.ecircuitcenter.com/Circuits_Audio_Amp/BJT Current_Source/BJT_Current_Source.htm Or have a look at fig 5.1 for other circuits: https://sound-au.com/ism.htm Bertus
  10. bertus

    Transistor as a switch

    Hello, Here is an example of the MJ1000 darlington: Bertus
  11. bertus

    my busted psu

    Hello, Reduce the size of the pictures to about 300 kB and you will be able to upload them. Bertus
  12. bertus

    my busted psu

    Hello, V12 in the given schematic is a standard diode type 1N4002. You can not test a zener diode with a DMM. To test the zener voltage a higher current is needed to test the zener diode: Many zener diodes need a minimum zener current of 5 mA. Bertus
  13. bertus

    Books on troubleshooting

    Hello, Here I found an couple of opensource books at the Internet Archive on trouble shooting: https://archive.org/details/electronic-troubleshooting-4th-ed./mode/2up It may not be the best scan, but still is usefull. And an other troubleshooting guide...
  14. bertus

    Book Reviews

    Hello, Yet an other troubleshooting guide: https://archive.org/details/troubleshooting-electronic-circuits-a-guide-to-learning-analog-electronics/mode/2up Bertus
  15. bertus

    Denon DCD-800 (circa 90's) CD player - CD spinning back and forth

    Hello, Did you have a look at the section "Wartung und justierung" starting at page 13 of the manual? It shows how to start the adjustment of the system. It also shows what equipment is needed for the adjustment. I assume you have this manual...
  16. bertus

    Cannot find this specific resistor, help!

    Hello, Looking at the manual, it is a 1 Ohms 2 Watt resistor: Bertus
  17. bertus

    Weird issue TDA7377 amplifier

    Hello, As said, page 6 of the attached UTC datasheet shows the signal at the standby and diagnostic pins. (see post #14). Bertus
  18. bertus

    Weird issue TDA7377 amplifier

    Hello, The heatsink ik shiny aluminium. That is not the best for radiation. See this section of the posted article: Radiation requires that the surface has the maximum emissivity of heat, and this means that its colour is important. Shiny gold anodised heatsinks might look great (if you like...
  19. bertus

    Comedy Thread

    Thanks nsaspook AAC
  20. bertus

    Weird issue TDA7377 amplifier

    Hello, You might be interested in the following articles on heatsinks: https://sound-au.com/articles/heatsink-amp.htm https://sound-au.com/heatsinks.htm https://sound-au.com/articles/diy-heatsink.htm Bertus
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