Magnum Deltaforce stuck in PA mode

[TX1000]

Hi,

My Deltaforce has CW mode not PA mode on the selector switch, so there should be no PA mode at all. However, when I just powered it on the LCD immediately showed "PA". I have pressed and held the reset button on the small frequency range selection board for more than 10 seconds but, when released, the radio still goes back to "PA" in the display. Are there any other options to reset the CPU or by any means get it out of PA mode?

Thanks

 

[undertaker]

Try pressing the band button. Or the function button…

 

[Xracerx13]

Post a picture

 

[9C1Driver]

I'll have to get my Delta out and check later. I think PA mode is either a turn to click option on one of the front knobs or maybe it was a push in on the same knobs. I think some Delta's had this and some did not.

 

[TX1000]

Thanks all.

Try pressing the band button. Or the function button…

Neither worked and I have tried both together and singularly turning the radio off and on. Tried a few other buttons in the off state and turning on but nothing makes a difference.

Post a picture

It's just a regular Deltaforce front panel with CW at the full clockwise position on the selector rather than the earlier models that had the PA in this position instead.


I think this may be a component or wiring fault since the MCU reset works as it should but has no effect on the PA mode. The tactile button reset should trump every other button reset/option I believe. Looking at the schematic, if the "PA IN" pin on the MCU is being held high then the PA mode is engaged. May have to open the radio up to see if there is anything amiss.

 

[undertaker]

Send it to superior cb he fixed mine no problems.....

 

[9C1Driver]

Check the third knob on the bottom from the left. The RB,S/RF,CAL,SWR,CW knob. See if it will push in or pull out to activate PA mode.

 

[TX1000]

Check the third knob on the bottom from the left. The RB,S/RF,CAL,SWR,CW knob. See if it will push in or pull out to activate PA mode.

I checked all the knobs and none pull out but I have confirmed what I suspected. Lightly touching the wire loom inside the radio at the back of front panel caused the normal LCD info to be displayed. I'll have to take the front panel off to expose the wiring to the MCU board to see if I can find the faulty connection.

 

[9C1Driver]

Ok good catch. Sorry my delta has the pa on the adjustable mode knob. And in the pic below you can see they added the function to the RF power on the Omegaforce S45.

 

[TX1000]

Okay, fault repaired.

I suppose at least some people are aware that Magnum/Dragon added the reset/frequency-range-options-jumper-board later in the Deltaforce's production life. As they made no changes to the printed circuit, I guess they just told the factory techs to solder the necessary wires from said board to the back of the MCU board (behind the front panel). It's far from ideal in that the six wires from the reset board are soldered to various SMD resistor ends and pads on the MCU board (see photo). They really ought to have added appropriately sized solder pads or holes into which these wires could be soldered. The result is that these wires have relatively weak joints with their corresponding solder points on the MCU board and not a great deal of movement of the wiring loom behind the front panel can lead to one or more of these wires detaching. This in itself won't cause the "PA" lockout problem I described previously, but it would mean that the reset/jumper options board functions would malfunction. Additionally, if R514 (100k) - to which the reset board's blue wire is soldered on one side - is damaged, i.e. goes open circuit, due to the blue wire being accidentally pulled then the MCU "PA IN" pin 4 goes low as no voltage (5V) is applied to it to keep the MCU in normal operation mode. This is how it works by use of the front panel selector switch on the early Deltaforces with the PA option instead of CW.

I found on my Deltaforce that the blue wire and R514 looked normal but in fact the resistor had gone open circuit, probably from a tug on the wire at some point. Fortunately, I had 100k, 0603 SMD resistors in stock and replacing the damaged one restored normal operation to the radio. I re-soldered the blue wire back in place once I had the new 100k resistor (R514) in place and all is now working well.

I hope this is useful to anyone who comes across this fault (corrected resistor number in image and reuploaded).