In article <27233@goofy.Apple.COM> pvh@apple.com (Pete Helme) writes:
>Does anyone have mods for this new dual band radio?  I heard something about 
>removing resitors D4 & D6, but would like clarification on that.  
>
>Also, does this radio have the same hole around 460 that the TH-77 had?
>
>Thanks,
>
>Pete Helme
>N6YLJ
>
>pvh@apple.com

d1-d6 are next the microprocessor under the edge of the copper shield. 

d6 is closest to the battery pack connector.

------

d4 out = Cross Band Repeat Enabled   use  F ( 1 second ) 0   to toggle

------

d6 out
d5 in  = CAP/MARS mod

------

d6 in
d5 out = Beyond Mars     Use F ( 1second ) BAND  to toggle extended band

         VHF normal tuning display  50 to 180 Mhz  ( AM detect 118-136 )
         VHF extend                300 to 400 Mhz

         UHF normal                400 to 512 Mhz  ( no holes )
         UHF extend                800 to 950 Mhz

------

The diodes are teenie-tiny surface mount types. Be SURE you have the correct
tools and know-how before attempting these changes. 

Standard disclaimers apply.

NOTE: The TH78A is NOT type accepted for transmit outside the amateur/cap/mars
      bands.

      PROTECT YOUR LICENSE. 

-- 
 __      __
|__)    (__`
|  \ick ,__)terling
-----------------------------------------------
Test Engineering
Commodore Technology Group  (215)-431-9275
UUCP ...{uunet,allegra,rutgers}!cbmvax!sterling


Well, you CAN make the newer version transmit out of band.  I was in
Michigan over the weekend and started modifying my dad's "jumpered" 78A
in various ways.  Taking out W1 enabled MARS/CAP frequencies and XMIT,
but not extended receive.  Next we took out W2, and it enabled extended
receive in both the UHF and VHF bands, but still no transmit.  We
soldered back W1 and it still had extended receive in both bands.  Next
came out D5 and still no out-of-band transmit.  Then came D4.  No
change!  We replaced both diodes and went for D3.  That was it!  You now
had out-of-band transmit throughout almost all of the VHF and UHF bands. 
I'm pretty sure either D4 or D5 controls the cross-band repeat, but
we didn't worry about, since we couldn't remember how to turn it on
at the time.  (Believe it or not, we were modifying my dad's radio on
his boat, without any documentation, just a soldering iron! :-)

Interestingly enough, my dad's radio goes up to 999.975 MHz, whereas
mine will only go to 949.975 MHz.  Not sure what the sensitivity is
like up there, but it is a difference.

Thought you might be interested.

-----------------------------
I have veryfied this , and D3 will indeed enable out of band transmit.

Other features enabled as side efects :

Clone mode - on+0 then ptt to upload DTMF stream
Poker game - on+m+ptt then you get first someting like the mind game ,
then a series of other games.
Sample : ??? what does it do ? on+dual will wipe out some of your memories
and put weird values into them
Hidden toggle : f longer than 1 sec. then m toggles someting , but what ?

to find : the autoanswerback paging feature.

Please e-mail any additions, corrections to luca@napoleon.eetech.mcgill.ca