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PCMA002F board
LC7132 PLL IC
Ah, the playboys rig of the 80's. A very popular mobile especially at night due to its "fairy light" display and with it's switchable bleep it became a bit of a favorite
CB even though as far as other CB radios went it was just "middle of the road". With it's scratch resist casing and all black look it was cosmetically a pretty
cool rig for it's day.

Now down to business. "Piggy backing" an Amstrad is NOT a straightforward affair. The display is negative bias so it won't directly piggy back as all you
would get is channel 19 on the mid block. Why is this? Because as the display from the LED drives the 7132 it cannot read anything if the power is reversed
so defaults to 19.
How do we get round this?
Either buy a ready made mid/uk board and fit the mid that way (Expensive) OR... fit two "Hex Buffer" inverter IC's between pins 1 to 8 of the 7132. This is made
easier if the 7132 and hex buffers are mounted on a piece of breadboard and linked together.
I personally use ST HCF4049UBE hex buffers.
CLICK ON THE PICS FOR A LARGE VIEW

Q/ Oh my cripes, look at all the wiring on that. It's so
complicated I will never be able to do it !!
A/ Yes it looks a lot but if you take it one step at a time
and your reasonably competent at soldering it wont
be too hard to do
Click the picture to the right for a much larger view of the connections.

Using breadboard instead of veroboard will save lots of track cutting and as long
as your solerings ok there shouldn't be any problems. Start off by fitting the IC's to
the breadboard noting which way around they are (remembering the view of the
wiring is from underneath) and bending the legs over as appropriate by looking at
the large view of the wiring.
Then wire up the solid black links from the 7132 to the 4049's.
The wire in the diagram with the stripes power the 4049's and the two from the
7132 link are the grounds for the IC's. Then for neatness I usually use ribbon
cable for the  channel selector wiring.
Click for a much larger Diagram
The wiring that goes to the 7136/7 depends how you personally feel you wish this adaption to fit into the rig. You can use short pieces of wire or, like
me, you may fit some more ribbon cable so that the board can be fitted away from the 7136/7 depending on what space you find inside the rig. After
fitting a seperate wire for the band switching I normally take the wires away from the board in the same direction and then tape some thin
cardboard/paper around the whole board and then use electrical tape to bond it all together and prevent any short circuiting when fitted into the rig.
A better idea would be to use a piece of heat shrink tubing like you see on many roger bleeps. This is available from most electronics outlets and
eBay.  Now you need to fit it into the radio.
Wiring this board into the rig is virtually the same as piggy backing a 7136/7 with a
7132. It's just that the 7132 now is built onto a larger board with two other IC's but
otherwise it's identical.

1/
The wires from pins 12,13,18,19,20 of the 7132 solder to the corresponding pins of
the
7136/7.
2/
On the radio cut the track to isolate pin 14 of the 7136/7 PLL chip.
3/ Cut the track to isolate pin 15 of the 7136/7 PLL chip.
4/
Run some wire from the track side of pin 15 to the middle connector of a 2 pole
switch (This will be the PLL common wire) then solder another piece of wire actually
from pin
15 of the 7136/7 PLL to one end of the same switch.
5/ Solder the mid/uk wire from the 7132 board you made earlier to the last position of the two pole switch. This is the UK/Mid control.
6/ Solder the 8 flying ends of the ribbon cable to the track side of the channel selector switch as shown in the diagram above.

That is basically it as far as fitting the board goes. Then it's just a matter of tuning in the top and bottom ends of the bands and evening out the power and
hey presto... you have an 80ch Amstrad working on the UK27/81 and PR27GB bands

NB. If the VCO does not fully stretch over both blocks then you can broadband the VCO by changing the 27uf cap which is to the rear of the VCO can to 33uf

DISCLAIMER
AS THIS RADIO HAS BEEN EXPANDED IT WILL NO LONGER BE TYPE APPROVED AND WILL BE ILLEGAL TO USE IN THE UK JUST THE SAME AS
ANY NON STANDARD CHANNELS BEING ADDED TO "ANY" CB RADIO. I DO NOT CONDONE THE ADAPTION OR USE OF ILLEGALLY CONVERTED
RADIOS AND THIS INFORMATION IS FOR EDUCATIONAL PURPOSES ONLY.
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CB Radio Repairers in the UK
CB Radio History from its early days