In my SG-230, it says 5DL on the top of diode. Don't know if that is an ID:
code of sorts.

73 Andy


"Dave Platt" wrote in message
...
All it says about the diodes is that they are either D5, D7, D9 etc. It
doesn't say what they are.

Yes, it doesn't say but if it were me, I would replace the
blown diodes with 1N4148's (assuming discrete diodes will
fit in the SMD pad space).

I wonder whether these diodes might not be MMBD4148 or some such?
These are 1N4148-type fast switching diodes in an 3-pin SOT323
surface-mount package.

Mouser and Digi-Key carry several variants of these. The MCC versions
are $.10-$.15 each in onesies and are good to 75V, 150 mA. The Diodes
INc. versions are around half a buck each in onesies, and are good to
75V, 200 mW. I'm not sure whether you'd want apples, or oranges :-)

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

In my SG-230, it says 5DL on the top of diode. Don't know if that is an ID:
code of sorts.

Yes, that's an ID code.

According to one set of notes I've found, Fairchild use 5D as the code
for an MMBD914, which is a fast switching diode similar to the 4148,
in a 3-lead SOT-23 case. The MMBD4148 would have a 5H code. The two
parts look *very* similar on the data sheets, and from what I've seen
in practice they're interchangeable in most applications.

If this is what you've got, then the pinout is as follows: if you
look down from the top of the diode, with the two-leaded side on the
left and the one-leaded side on the right: pin 1 at the top left is
the diode's anode, pin 3 at the right center is the diode's cathode,
and pin 2 at the lower left is not connected to the diode.

The pinouts are the same for the MMBD914 and MMBD4148.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

I have checked diodes D4, D5, D6, D8, D9 and D10 and all of them check out
OK.

All 5 LED's are lit and stay lit when I key and de-key the transceiver.
There is no clicking of the relays.



In the SGC Smartuner troubleshooting that can be found here
http://www.sgcworld.com/Publications...oubleshoot.pdf it says,



For newer SG-230's and other SGC antenna couplers:

1. If LEDs do not light, RF sense diodes and bypass capacitors are suspect.
Also

check Q1 (ZN2222) and CPU chip (68HC711).



2. If LEDs do light and coupler does not initiate tuning, check the CPU
chip. On rare

occasions, the mixer A1 may fail. Verify if you have clock signal on the
output of U3

(74HC393) chip. Verify DC voltage at U11, Pin 1 during transmit. Check R1
and if

no voltage is present, check all 4 sensing signal inputs to the CPU chip -
FWD, REV,

PHASE, IMPEDANCE. If you have an input signal, you should see the
appropriate

LED light. Also verify RF PWR signal is present.



How do I check the mixer A1 to find out if it's working?



What equipment would I need to check for a clock signal on the output of the
74HC393 chip?



What or where is U11 and how can I determine what one is pin 1?



R1 has voltage.



73 Andy





"Dave Platt" wrote in message
...
In my SG-230, it says 5DL on the top of diode. Don't know if that is an
ID:
code of sorts.

Yes, that's an ID code.

According to one set of notes I've found, Fairchild use 5D as the code
for an MMBD914, which is a fast switching diode similar to the 4148,
in a 3-lead SOT-23 case. The MMBD4148 would have a 5H code. The two
parts look *very* similar on the data sheets, and from what I've seen
in practice they're interchangeable in most applications.

If this is what you've got, then the pinout is as follows: if you
look down from the top of the diode, with the two-leaded side on the
left and the one-leaded side on the right: pin 1 at the top left is
the diode's anode, pin 3 at the right center is the diode's cathode,
and pin 2 at the lower left is not connected to the diode.

The pinouts are the same for the MMBD914 and MMBD4148.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Andy wrote:
What equipment would I need to check for a clock signal on the output of the
74HC393 chip?

Unfortunately, you need an oscilloscope for troubleshooting
at that level.

What or where is U11 and how can I determine what one is pin 1?

Good question. I don't see U11 on the schematic.
--
73, Cecil http://www.w5dxp.com