|Extender Card tips..older ham gear..ie ft301, ft221 yaesu black transceivers and other gear of similar
vintage, tips to make your own extender card from Vector board surplus circuit cards and wire and edge
connectors -- May 22-2013 by Earl Andrews VE3AB -- Junkbox parts to make an ugly but effective
extender card for ham radio servicing of older rigs-- or you can buy one from a fellow who makes them and
sells them on ebay and qth.com swap list.
Also..I wrote a bit at the end of this article on the dual gate mosfets I tested in the FT301 receiver front end
section. (I sell components and test them before selling..whenever I can)-- Used parts I sell on Gentlemans
Agreement..try it in your circuit..if it works..ALL IS GOOD..if no..I will give you a full refund on your part(s)
and your shipping charges as well!!!-- Small orders only.. and this is for used PULLED PARTS like
Above left picture: My own (ugly but very functional)
exteder card. I used it with my FT221 2 meter multimode
and it worked great.
You can see the other new Vector Board part nr 3682
board that I laid under my homebrew extender card. The
gold fingers seem to line up perfectly. I went looking
around for more Vector nr 3682 material and found the
large card in the plastic wrapper. The fingers seem to be
the correct spacing for mating up with older solid state
rigs such as Yaesu FT301 and FT221 and perhaps as
well..Atlas 210x and perhaps some heathkit rigs as well.
Several People have written me concerning where to buy
an extender card for service..so I thought Id write up
Below left..some edge connectors that seem to be correct
pin spacing as well.
I plan to make up another extender card for service work.
I will use the wires to go from top connector to bottom.
It worked..even though it looks a bit ugly.
This is a picture (above) I snagged off
the web of a professional extender
board for servicing some Yaesu rigs.
I find ..when they do go up for
sale..they are fairly expensive to buy.
So..I have decided to make my own.
73 earl ve3ab ..hamelectronicsmagazine.com &
www.earlandrews.com (mirror site) and my new site:
www.earlandrews.info (which is about outdoors kind of stuff).
Here's a link to my home page for ham radio and
electronics...click here - 73 earl
June 28th 2013.. Here Iam back at work fixing some
circuit boards for the FT301. This time I have
decided to use an extender card I bought from a
fellow in Rhode Island who makes up these
extender cards for older radios such as Heathkits
and Atlas rigs and the FT301 and (I think) the
---> He is pretty easy to find on swap lists such as
the one on QTH.com and he is probably still on
At first I was a little hesistant about using his
board. I thought the conductive tracks were a little
bigger than they should be. Up until now..I had
been using that very ugly extender board with
yellow wires pictured at the top of this page!
Well I used this extender board shown in this
picture from that fellow and I plugged and
unplugged about 20 or 30 times as I was trouble
shooting the Filter Boards I had around here and I
was checking for bad solder joints ect and
bending the board and flexing it as I worked and
this extender board worked great.
Pictures of the board are shown below.
Above picture some edge connectors from my junkbox (used ones) that seem to be the right pin
An extender board is a real asset when making measurements. I must admit..I have an advantage in troubleshooting because I have extra spare boards of all sorts
and I can take a close up look under magnification to find measuring points (ie the base of a certain transistor Q102 or whatever). I can also insert a good working
circuit card and make measurements of what "should be" ..then I can plug in the defective board and find a problem voltage or lack thereof ect ect. --
My FT301 has an RF board that has a plug in socket for both
dual gate mosfets.
The one closest to the bottom of the screen is the RF
amplifier transistor. I built a radial lead transistor from a
BF981 dual gate mosfet by soldering on leads. It performed
just about as well as a more expensive 3N211.
|June 25, 2013.. I measured up a good number
of the dual gate mosfets in my collection to see
how they performed.
I thought Id mention ..here on this page.. that while doing
the work on the Filter Board..and I had my FT301 on the
bench..I also measured up some Dual Gate Mosfets I had
bought in bulk to see how they performed.
The 3N211 seemed to produce a noticeably stronger audio
signal..likely a bit more than 3db over the 40673s and
40823s and other dg mosfets in my collection. Just thought
Id mention this work in passing.
Notice the pin 1 and 18 marked on the board. If you go to the schematic you will see the little bubbles on the edge of the schematic for each board..ie
the Filter board ..like the one Im doing here. Voltages that should be present (DC voltages) are easily measured by using your vom and probing the
various numbered pins.
Thanks for reading this little article. Earl VE3AB 28 June 2013