ubitx v5 down: IRF510 heatsink very hot immediately after turning on the radio #ubitx-he llp #ubitx #ubitx-he

Jerry Gaffke

K3 could be just fine.

With power off, the relays are in their receive position as shown the the schematic.
The antenna is grounded for your DC ohmmeter by way of T2, via L4,3,2,1, K1 and K2

As per my previous post, my guess is that when you power up it immediately goes into transmit mode.
Now the antenna is grounded by way of T11, via KA1,2,3, L11,12,13 and K3.
In either case, all of TP1, TP2, TP8 and the antenna are DC grounded.
That would be true of a perfectly functioning rig, except it should not power up in transmit mode.

I'm guessing a miswire or two in following the hfsignals ubitx wireup instructions.
Perhaps in that 4.7k resistor that should be on the morse key line.
And perhaps also somehow in how the mike got wired up, such that plugging in the mike
somehow brings it back to receive.

On Sun, Apr 21, 2019 at 11:15 AM, Jens Kaemmerer wrote:

with the uBitx turned on *or* off:
continuity exists between TP8 (TX path) and ANT (antenna center conductor)
and TP1/TP2 and ANT

This is strange - based on the schematic it should be:

Either there is continuity between TP1/TP2 and ANT *or* TP8 and ANT - not

My conclusion:
Maybe the relay K3 is damaged (or somehow 'stuck').

Adrian Chadd


If you disconnect the raduino and power up, does it still go into TX mode? (Just to rule out something on the raduino side holding the TX line high.)