TH-77
 
    I don't know about TH-77A which I think is an export version of TH-77,
but I can give some information on TH-77, which I own.  This set 
originally can TX/RX on 144-146MHz, and 430-440MHz.  By cutting a green 
line about an inch long connecting between a capacitor and pin 4 of
CPU(HD404608H) enables receiving on 118-174MHz, 335-512MHz, and 800-950MHz.
    There is another modification which let you transmit on wider range
of 136-174MHz, and 400MHz-460MHz.  This can be done by connecting pin 7 
and 14 of HD404608H with 33Kohm register.   The last modification
is to connect pin 6 and pin 14 with 33Kohm register, which enables 
transmission on 350-460MHz, but disables receiving 118-174MHz and 
800-950MHz instead.
    As an additional information, there is an interesting feature 
which let the transceiver to be a cross band repeater.  
This can be done by pressing UP arrow key when you turn the power on.  
To release this mode, do the same again.
    At least in Japan, these features are not documented in the manual, 
and Kenwood does not officially announce these,  so I'm not sure 
whether Kenwood service center provides information on TH-77A at your 
place or not.
--------------------------------------------------------------------
In real Life:  Yutaka Muto
JUNET:         muto@nttcoin.ntt.jp
CSNET/ARPA:    muto%nttcoin.ntt.jp@relay.cs.net
HAM:           JH1VWP ex.VE3VWP
Organization:  NTT Communications and Information Prosessing Laboratories
Physical mail: 1-2356 Take Yokosuka, Kanagawa 238-03 Japan