Re: Damaged my Si4734


Sorry to hear that Roy. I guess it might be a smart precaution to
short AMI to ground while soldering the antenna in.

Shoot me an email with your shipping address. I'm sure I can find
a replacement part around the lab here.

I don't think that a C40 part is likely to work in the G8/PL-3XX
radios until Tecsun ships it. (And I have no clue if, or when that
might be.) From playing with my PL-300, I believe it is using
a firmware 'patch'. So, although the C40 firmware should be
backwards compatible, the radio (which expects a B20) will try to
download patch code during the power-up process. Unfortunately,
patch code is specific to the exact firmware revision, so the
likely result is program corruption and CRC errors.


--- In ultralightdx@..., "Roy" <roy.dyball@...> wrote:

Hi All

It had to happen after many multiple operations and hundreds of hours of
software development with my old faithful G8 I have damaged my Si4734
chip. I was sure that this was going to happen in the dozens of times I
made connections to the control lines. But no, a careless slip of a
Loopstick wire brought me undone.

I was unsoldering one of the loopstick wires when the heat travelled so
quickly up the 660 strand Litz wire that it burnt my finger. 660 Litz is
really flexible and with a nice tinned end it is relatively heavy. It
seemed to fall across the circuit board snapping and popping till it
came to rest. A coil made from 660 Litz is very low resistance.

Smoke was coming from the SW switching FET. Luckily I have one of these
and it was easy to replace. However the radio was deaf on AM with only a
bit of noise right at the bottom of the band, FM worked fine. To make
double sure I disconnected the switching diode thus eliminating the SW
pre amp this did not help. I also checked the AC coupling capacitor

Connecting the radio to my software showed that on every station that
the varactor was showing max count and capacitance (6143) so it is not
tuning. I have a really small propane torch so it only took 30 seconds
to remove the chip from the circuit board ready for the new one.

I figure this is a blessing in disguise as I really want to try out the
Ver40 firmware. The trouble is that those suppliers who stock the chip
only have Ver20 and with the stock numbers they have I don't think
they will be stocking Ver40 for a while. Has anybody in the group seen a
Si4734-C40 in their browsing for sale? I tried but they only
have the V20. Their price is good for the V20, about $15.00 but they
want $39.00 to ship an item 3mm square that is probably so light you
cannot way it.

I cannot speak highly enough about the Si4734 chip; it is a sturdy well
protected little chip. This was my fault so be careful when working with
660 Litz wire. Also if ever you remove the Si4734 from the circuit board
go out of your way to put it some ware safe as I have already misplaced
the old one. I had it on my bench and when I looked for it, it was gone.
It cannot have gone far and should turn up.

Cheers Roy.

Join { to automatically receive all group messages.