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CB Radio Repairers in the UK
CB Radio History from its early days
The baby of the Midland World. Small, black and sleek with
minimal controls and NO signal meter, just TX/RX lights. Volume,
squelch and Channel controls on  the front as well as up/down
buttons, hi/lo switch on the rear.

There are only 3 adjustable RV (horseshoe) resistors in these so it's
pretty simple. The one right at the front between the Vol and Sq
controls (RV101) is the squelch adjustment. The one by the PLL IC
(RV104) is the Mod or deviation and the one towards the rear
(RV103) is the main TX output power adjust.  
Slightly larger than the 099 is the Midland 77-104, again small,
black and sleek with a standard type channel selector and a
bargraph LED display for tx/rx. Volume, squelch and Channel
controls on  the front, hi/lo switch on the rear. Although the mic
connection is still a 5 pin din these have a thread on them so
they can be securely screwed into position. This has a 'D'
version which is a newer design.

There are a few more adjustable RV (horseshoe) resistors in
these but it's still pretty simple.
The Midland 77-805 is very similar to the 77-104 in looks and control
functions. It differs though as it is the hand-held version with a special
antenna attachment on the rear for the telescopic antenna.The power
socket is a 3.5mm jack female plug and the battery pack is in the
carry-case which can be removed totally and the radio used in the same
way as the 104. It has no external speaker in the case as this is built in
to the microphone. There is also a 'D' version which differs internally  
This model was from 1990
No channel display or only counts up to 9. Try D302 (8v1 Zener diode)
or R310 which burns out. Both are located at the back of the mic socket.
Increase RF power to 8w. Link the two legs of RV103 together (ignoring the center leg)
and re-tune the RF output stages.
Faint modulation - Replace Q306
LED driver is TL489CP (IC2)
No TX power - replace R147 (resistor supplying power to output stage)
Very Faint outgoing audio - Q306
No received sound- but Audio IC OK, Q602
No TX power - Replace R147 which supplies power to the TX Transistor


MIDLAND 77-805UK CIRCUIT DIAGRAM (LARGE)

MIDLAND 77-805UK COMPONENT DIAGRAM (LARGE)
Very common fault - RX and TX goes on and off, dry joint on centre of board
or voltage regulator 7808.
Low Power - Only ¾W on full power, R165 (181k) 77-104D
1
9

F
O
R

A

C
O
P
Y

A
N
Y

B
R
E
A
K
E
R
S

A
N
Y

T
A
K
E
R
S

C
'
M
O
N
If you look closely you will see this radio (805D) has the mid block PLL 'piggy backed' on to the original PLL. I did this conversion back
in 1995 and the PLL was difficult to get hold of back then, also access was limited to solder the PLL's together so some of the joints
are a bit blobby. These days I remove the PLL and join them together on the bench with plenty of room. I would guess unless you have
a scrap radio with one in it would be almost impossible to source one now, or if you did it would be at a premium. I found some but they
are from abroad here
www.avera.eu and type C5121-00 into the site search engine
Midland 77-805D(UK)

Front View
PLL IC View 1
PLL IC View 2
PLL IC View 3
Rear View
Midland 77-805UK

Front View
Inside front view
PLL IC View
Rear View
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