2.0 KiB
2.0 KiB
Hardware errata
Rev 1
- R307 needs more clearance from D400
- Pins 1 and 12 of U502 need pull-downs
- Pin 1 of U501 needs pull-up
- D203 reversed polarity
- R236 and R234 are swapped
- Q301 needs to be NPN, change to BC817
- increase R307 -> 3.3Kohm and increase R500 -> 33Kohm
- C201: oscillates at 0 and 1nF, stable at 100nF
- add clamp diodes to GND on op-amp outputs to ADC when op-amp has negative supply
- R214 -> 7.5k
- LM339PT is in TSSOP package. Change for SOIC P/N
- GDT200 minimum firing voltage is too low
- the relay model should be changed to 9001-05-00. 9001-05-02 is an undocumented normally closed variant.
- D504 should follow the schematics in its datasheet
- R502 should be connected to VCC
- R502 -> 240 ohm
- C500 -> 1nF
- R234 -> 7.5k
- Q104 -> DMN3404
- R114 -> 470 ohm
- R115 -> 4.7k
- R227 -> 470 ohm
- R228 -> 4.7k
- review values of R226 and R113
- C100 -> 47pF NP0 AVX, R107 -> 100K, C101 -> 0.1uF
- use crystal type recommended by the MCU datasheet
- add connector for OLED display?
- enlarge holes to fit M3 screws comfortably
- add 15M resistor between A and FIL-
- power U200 from a small negative voltage instead of GND
- review choice of filament flyback output diode
- invert LED position so that the Ethernet LED is closest to the connector
- invert polarity of LEDs (Ethernet LED polarity cannot be programmed)
- change D351 model to MBR1645
- add snubber on D351
- add heatsink (Seifert-KK633) to D351
- move D351 further away from transformer for heatsink clearance
- add plated-through holes and pads for mounting rods of BNC connector
- simplify FBI circuit, 2 ranges only (typ. 8mA and 45mA), remove diodes and neglect MOSFET leakage
- to support different case designs, replace the holes on the connectors side with slots. One of the case designs requires holes whose center is at 11.5mm from the board edge.
- review choice of external LED connector type and clearance
- if using a non-polarized connector, change pinout so that connecting the LEDs the wrong way cannot cause damage