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A bit different, but I used TN0110s for my last QDX build instead of the BS170s as has been discussed in other threads here, and then used a Wakefield LTN20069 heatsink drilled and tapped.? (pics

I re-checked continuity of T501, and looks good. Then checked voltages, and all P & Secondary are zero volts with the QMX powered on in RX. But that's with L502 removed, so I'm guessing that's why

Mike CWTerm uses RTS/DTR keying, not CAT. I don't have a QCX so I don't know how it handles RTS/DTR. Usually, on older rigs, with CWTerm you have to use a keying circuit external to the

Looks good!

I'm seeing 2.436 V gate to ground on the 2 BS-170's near board edge, and 2.46 V on the "lower" 2. I am running my 12V QMX at 9 V for these tests. Total current draw is showing 110 in RX and 130 mA in

That's encouraging! While L502 is still removed also measure the gates while TX is active. It will probably read OK but one-step-at-a-time caution is still prudent. JZ

Hi John. With L502 removed, the powered up QMX is now drawing 110 mA power, and I measure 0 V from Gate to ground on each of the BS-170s, and that's with the shorted transistor replaced with a new

Thanks Chris, I think I'm exceptionally outgoing at times. Not one to miss an opportunity like this, to get propagation data from the far north, I got a hold of their crew and asked about at

I have yet to start my builds (I bought one of everything), but I've been reading the posts here for a while and slowly getting prepared.? I have even bought a pack of BS170s in anticipation of

Hans, Best wishes on getting well soon. ?Glad you have the support of your XYL. ?It’s amazing you’re able to accomplish all you do, and still have time for self and family. Take care! Todd

Roy, I strongly advise you try to figure out root cause before you replace the bad transistor. At a minimum, disable the power source to the PA by lifting a leg of L502, or removing it

After months of operating as a WSPR beacon my QDX failed. Q7, the reverse polarity protection, has gone open. The assembly manual tells me that it has been been replaced by a more

On my "hot" BS-170, the Drain and Gate show a direct internal short. So the question is, if I just replace that one, am I good, or more likely, I need to find the root cause of why it went bad ...

Hi John. No, IC503 remains cold after power up (and RX only). -- 73 de Roy - KI0ER Littleton, Colorado USA

Get yourself a MORTTY https://hamprojects.info/mortty/ -- 73 Jim K1IR

Roy, Is IC503 warming during RX as well? JZ [email protected]> wrote:

BTW, here is a link: /g/QRPLabs/topic/80102109 73, Mike KK7ER

Ludwig, A good step towards figuring this out is to observe or measure the gate signals at each bank of BS170s. If it is not what is expected, we can begin to peel down the possibilities at that

With display removed, I powered up my QMX and watched the PA transistors with an infrared camera. One of them lit up in the camera within seconds of power up. It was the top-left PA transistor that

Hi Gary, Did you ever try CWTerm with a QCX? If it's not using CAT commands then I don't understand how it is working. 73, Mike KK7ER