Re: QCX burned up after connecting GPS
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Take a close look at Q1, 2, 3 to see if burnt followed by Q6 as they are part of the power amp circuit. Allare all most likely damaged and will require replacing.? I know - I've transmitted without realizing antenna not connected. Just cut off the transistor body and heat the solder pad and pull each leg out.?
Unfortunately the smoke happens very quickly with no warning so with the QCX always have an antenna or dummy load connected when powering up or experimenting.? Alternatively, put it in practice mode.
The GPS is shared with the keying pins as there were no spare pins available on the microprocessor to implement the GPS direct.
The manual explains the beacon function well so take a look at that section.
Menu selection 8 has the GPS calibration selections for the system and synth oscillators.
David VK2JDR
On 27 January 2018 at 17:57, Alan G4ZFQ <alan4alan@...> wrote:
I think it was but everything happened so fast it¡¯s hard to remember , I was just going to calibrate the crystals , I didn¡¯t know it was transmitting... but now when I plug it into power it starts smoking again , stuck on TX? Can I test with multimeter ?
Ted,
Quite a few have been caught out like you.
There is a configuration setting required before attaching the GPS otherwise the QCX goes to transmit.
Then, if no dummy load is attached one or more of the PA BS170s blows AND so does Q6.
If they are not all replaced there is confusion, or even more damage.
Hans has a good troubleshooter but I do not think this very important point is included. At least I cannot find it although there are many references in past posts.
73 Alan G4ZFQ
Was the QCX connected to the antenna at the time the GPS was plugged in?? If not, then the output transistors will be burnt out due to no load as the GPS unit will be "keying" the QCX.
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