It looks like some of the SM 3-pin diodes D10, D9, etc have failed. I was
only testing with a 100 watts although it was with a very high SWR at the
time

Do I have to go to SGC for the diodes or is there a replacement that I can
use instead?

73 Andy


"Andy" wrote in message
...
Chris,
I will have a look, but its unlikely to be corrosion due to it being
stored in its box in my cupboard for the lat 4 years. But it might help
others.

This might help you though. Some one did tell me once to seal the SG-230
with silica gel after putting some silica gel in side so soak up any
moister. Its those little packets you get inside the box with new
electrical items.

Thanks


"Christopher Cox" wrote in message
...
Hi Andy,

I had a similar problem with my SG-231. It turned out to be a corrosion
problem in the power/control connector. This made a electrical connection
to be made to the Reset/Hold/Tune leads. There was a little corrosion on
the back side of the circuit board as well. Look up into the male
connector and disassemble the female.

I cleaned up the corrosion problems with a dental pick and fine wire
brush. I resealed the connectors with epoxy. The silicon sealant SGC used
seems to be effected by moisture as it had become milky looking till it
dried out.

Hope this helps.

Chris


Andy wrote:
Hi all

I purchased the SG-230 about 4 years ago. I took it out of its box
yesterday for the first time and tested it out on a light bulb as a
dummy load and all worked fine. It found a match on all HF bands.
I connected it to an antenna today and it would not tune. It would not
reset with the Smartlock. I took the back off the 230 and noticed when I
apply the 13.8 Volts all the relays click once and they
all stay in that position until I disconnect the power and if I apply
RF, 10-80 watts when the 230 is powered up it does nothing, it doesn't
even attempt to tune.. I have also tried 2 lengths of 10ft wire and it
does nothing.
There are five LED's inside that are all on (green).

Does anyone know what is causing this problem?

73 Andy

Andy wrote:
It looks like some of the SM 3-pin diodes D10, D9, etc have failed. I was
only testing with a 100 watts although it was with a very high SWR at the
time

Do I have to go to SGC for the diodes or is there a replacement that I can
use instead?

My SGC-230 manual says those are 1N4148 high speed
switching diodes which are one of the most popular
diodes of all time. They should be readily available
almost anywhere.
--
73, Cecil http://www.w5dxp.com

Cecil,

I had a look at the 1N4148, they are 2-pin.

The diodes in mine are Surface mount 3-pin.

Are the 1N4148 diodes for the old version board, before year 2000?

My board is the newer version, after year 2000

73 Andy


"Cecil Moore" wrote in message
. ..
Andy wrote:
It looks like some of the SM 3-pin diodes D10, D9, etc have failed. I was
only testing with a 100 watts although it was with a very high SWR at the
time

Do I have to go to SGC for the diodes or is there a replacement that I
can use instead?

My SGC-230 manual says those are 1N4148 high speed
switching diodes which are one of the most popular
diodes of all time. They should be readily available
almost anywhere.
--
73, Cecil http://www.w5dxp.com

Andy wrote:
Cecil,

I had a look at the 1N4148, they are 2-pin.

The diodes in mine are Surface mount 3-pin.

Are the 1N4148 diodes for the old version board, before year 2000?

Yes, my manual is copyright 1994.

My board is the newer version, after year 2000

What does your schematic say about those diodes?
--
73, Cecil http://www.w5dxp.com

This is the problem that I have got with my SG-230.
I purchased it new myself. My PCB board is an Q50102000-E. it is what they
call the newer version, after the year 2000.

My manual is a Revised: November 2000. The Document number for the
schematic, Q30102000E Rev: A Dated February 17, 1992. It looks to me to be
the wrong schematic for my PCB board. Maybe some one might know if it is or
not or have the correct one that they can send me?

All it says about the diodes is that they are either D5, D7, D9 etc. It
doesn't say what they are.

73 Andy



"Cecil Moore" wrote in message
. ..
Andy wrote:
Cecil,

I had a look at the 1N4148, they are 2-pin.

The diodes in mine are Surface mount 3-pin.

Are the 1N4148 diodes for the old version board, before year 2000?

Yes, my manual is copyright 1994.

My board is the newer version, after year 2000

What does your schematic say about those diodes?
--
73, Cecil http://www.w5dxp.com

Andy wrote:
My manual is a Revised: November 2000. The Document number for the
schematic, Q30102000E Rev: A Dated February 17, 1992. It looks to me to be
the wrong schematic for my PCB board. Maybe some one might know if it is or
not or have the correct one that they can send me?

This one is copyrighted Nov. 2000

www.sgcworld.com/Publications/Manuals/230man.pdf

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).
--
73, Cecil http://www.w5dxp.com

Yes, that is exactly the same manual as mine.
How would I connect the 1N4148 2-pin to the 3 pads that are under the SM
3-pin diodes, will this even work?

If it is possible I would have to mount them vertical.

73 Andy


"Cecil Moore" wrote in message
. ..
Andy wrote:
My manual is a Revised: November 2000. The Document number for the
schematic, Q30102000E Rev: A Dated February 17, 1992. It looks to me to
be the wrong schematic for my PCB board. Maybe some one might know if it
is or not or have the correct one that they can send me?

This one is copyrighted Nov. 2000

www.sgcworld.com/Publications/Manuals/230man.pdf

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).
--
73, Cecil http://www.w5dxp.com

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
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