Discussion in 'Amateur Radio Amplifiers' started by WA6MHZ, Jan 11, 2019.

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  1. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Counterfeit parts from China (mostly) are really common.

    We build stuff for the Air Force and you should see the "restrictions" Northrop-Grumman places on us with respect to that. Every single chip we buy must be serialized and X-rayed and supplied with the X-ray film or electronic image file (showing the S/Ns) and the data to trace every part back to its origin.

    That "costs a bit more," but evidently they think it's worth it and since they're paying the bills, we can't debate this.

    This restriction applies mostly to older parts; it doesn't apply to new Intel Xeon CPUs and stuff purchased directly from authorized U.S. Intel distributors. But it applies to everything that's old or EOL, including 386/486-series chips (long discontinued, but still part of these designs!) and even TTL gate arrays and stuff. Once stuff is discontinued from current manufacture, it's all suspect.
  2. WA6MHZ

    WA6MHZ Subscriber QRZ Page

    Some of the problem is the CMOS can't drive LEDs directly, I used to think they could. So that means each and every led needs a transistor to switch the level to ground, I installed 16 2N2222s, 4 Dip resistor packs and wired them all up. So much for my surplus board space. the wiring was very intense!
  3. WA6MHZ

    WA6MHZ Subscriber QRZ Page

    Todays adventure in Homebrew is the Front panel logic box. This will be driven from the meter PCA inside the unit where the 5V regulator resides.
    6 switches and 16 LEDs are on the front panel.
    swiches on the right are (from top to bottom) "START" , "STOP", "CW/FM", "SSB" ,
    Switch near the panel center is "TXT TEST" Switch on the center right is "Meter Advance"
    we will get to that and the 8 LEDS on the right later.

    Across the top is Green LED for "RUN". Red LED is "HV ENABLE" This will be converted to a FLASHING LED later on
    Green LED to the right is the RECEIVE LED

    Next Row down. Yellow LED is "STANDBY" White LED is "WARMUP", RED Led to the right is 'TRANSMIT"
    Final 2 LEDS next to the CW and SSB pushbuttons are just that. Showing yellow "CW/FM", and Red for "SSB"

    Here is the 2 assemblies, Front panel and Logic board
    Notice the Front panel plugs into the logic board with two 14 pin Ribbon cables.
    The logic board is very busy and not completed yet! Still have to add the meter switching circuit (CD4017) and 555 switch debouncer. Then there is the HV ENABLE Flashing circuit.
    At start up, the logic defaults to "RECEIVE", "STANDBY" and "SSB"

    Pressing start Lights the "RUN" LED and extinguishes the "STANDBY" LED.
    It also starts the 555 timer for the 1 minute warmup, lighting the WHITE "WARMUP" LED.
    After 1 minute, the White LED extinguishes and the RED FLASHING "HV ENABLE" LED lights.

    AT the end of a session. Pressing STOP returns the unit to STANDBY and powers down the HV.

    Pressing CW/FM enables the switching of the BIas and Screen changes from CLASS AB1 to CLASS C for CW.
    Pressing TX TEST does just that. It is in parallel with the PTT on the rear panel. Green LED RX extinguishes and Red TX Lights. Also switches the bias and screens from RX to TX.

    Very complicated, but I am tickled to say the logic works great!
    Whether RF messes with it remains to be seen.

    Yes, it could have been done with an ARDUINO, but I LOVE my 4011s!!

    ON to the meter switching circuit
    KB4QAA, W7UUU and KD2ACO like this.
  4. WA6MHZ

    WA6MHZ Subscriber QRZ Page

    The logic box will be bolted to the frontpanel in the area where the Power Transformer it. I see 80mA drawn in the power on condition. another ribbon cable interfaces to the Meter PCB.
  5. WA6MHZ

    WA6MHZ Subscriber QRZ Page

    Cat Ranch Electronics!
    WHERE the primary objective is WHIZ BANG!
    Lets hope there is NO BANG in WHIZ BANG!!!!
    K9ASE likes this.
  6. WA6MHZ

    WA6MHZ Subscriber QRZ Page

    Today we got the High Voltage flasher to work. (Not easy, had to add another CD4011! CD 4011s don't like other activities going on on the same chip). The flasher didn't work until I built it on a separate chip! Spare gates are used for Invertere and light duty logic switching when sharing an RS Flip Flop.

    Next up was the very complicated METER Selection circuit. This uses a CD4017 to step thru the 8 meter postions. In each postion, a DPDT relay is keyed on the meter board. to switch the meter interface. a special relay swaps the meter polarity when the BIAS supply is selected. Another special relay switches the Meter so it is Isolated to measure the Screen Grid current and Grid Current. A Cal pot for each postion is above the corresponding relay. this box can be mounted Remotely near the rig for full remote control of the amplifier. The Analog 0-50 uA meters are still used on the original front panel.

    Now to work on the Meter calibration circuit.
  7. W7UUU

    W7UUU QRZ Lifetime Member #133 Volunteer Moderator Life Member Platinum Subscriber QRZ Page

    My goodness Pat... you can do ALL OF THIS...

    .....But WHY did the HW-9 that you built "new in the box" never get finished????

    I only ask here since it seems it's the only thread you check on anymore....

    N2EY likes this.
  8. N2EY

    N2EY Premium Subscriber QRZ Page

    "The more they overthink the plumbing, the easier it is to stop up the drain"

    N2SR, K9ASE and WA7PRC like this.
  9. WA6MHZ

    WA6MHZ Subscriber QRZ Page

    Sue has the HW-9 and is still trying to get it work. Something to do with the cores on the coils. She almost got it working, almost! She will get around to it again some day
  10. N2EY

    N2EY Premium Subscriber QRZ Page

    "Engineering is the art of doing for 10 shillings what any fool can do for a pound"

    "Hundred dollar solution to a fifty cent problem"
    N2SR and WA7PRC like this.

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