• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

ICOM IC-T90A Extended mod Tx and Rx Mod

AudioShockwav

Extraterrestrial
Staff member
Apr 6, 2005
8,966
8,634
593
Nor Cal Sierra Nevada
The ICOM IC-T90A transmits on 6 meters, 2 meters and 440 MHz and also has wide band AM, FM and A Wide FM scanning receiver.
Here are the instructions for expanding the TX

To expand the HT for full band coverage ( 45.300 Mhz to 240Mhz and 300Mhz to 584Mhz ) Remove the Battery, underneath you will find a plastic cover. Peel it off and underneath you will see 3 SMT Diodes, carefully remove them, replace the sticky cover, istall the battery, Do a Reset on the radio and you are done.
Below are before and after pictures ( the board was removed from radio case )
After resetting the coverage and power output will more of less be as follows:
45.300 mhz 3.8 wattsto75.100 mhz 1.5 watts Power output as specified in the ham band.to89.000 mhz Output tapers down until pll unlocks.90.700 mhz Pll locks very low output.to92.500 mhz 0.8 wattsto110.000 mhz 0.8 watts117.800 mhz 1.0 wattsto179.900 mhz 2.0 watts Power output as specified in the ham band.to238.000 mhz Output tapers down until pll unlocks. Output in the 220 band is very low.300.000 mhz 0.5 wattsto540.000 mhz 0.5 watts Power output as specified in the ham band.to580.000 mhz Output tapers down until pll unlocks.Mod does not open the blocked cell area.
The above was verified on a Cushman CE50 service monitor. Even though the power output is low out of band, and near the edges of the pll lock range the frequency accuracy suffers, it is still useful for testing purposes. Transmit is FM only.

73
Jeff
 

Attachments

  • ic-t90a_trx1.jpg
    ic-t90a_trx1.jpg
    30.2 KB · Views: 1,852
  • ic-t90a_trx2.jpg
    ic-t90a_trx2.jpg
    25.9 KB · Views: 1,618

I'm going to be doing this to my roommate's Icom soon. I see that you said the board was removed from the case. Is this fairly easy to do? I've done mods on my VX-6R and my other roommate's VX-8R. I have taken my VX-6 completely apart for cleaning and to replace the scratched plastic screen and it was pretty straight foward. The VX-6 and the t90a look pretty similar; is it just as easy?
 
I did the mod on my T-90a years ago when I had one (sold it later) and I seem to remember that it was pretty straight forward.
 
I currently own (2) of the ICOM T90A HT's & one has this mod & the other does not.They both work great.If you do the mod remember the antenna is NOT designed for the band coverage that the HT will have after the mod so do NOT transmit say on the 220 mhz band without a proper antenna or you will blow the finals in the radio pretty fast.I have seen so many of these HT's with blown finals & all of them had the mod done.A few admitted they screwed up but some refused too accept the fact they forgot.These two make it three that I have owned & I have have had Zero issues with any of them.If the HT had dual receive & D-STAR it just may have been the Perfect HT for me.

W4KVW
 

dxChat
Help Users
  • No one is chatting at the moment.
  • dxBot:
    Tucker442 has left the room.
  • @ BJ radionut:
    LIVE 10:00 AM EST :cool:
  • @ Charles Edwards:
    I'm looking for factory settings 1 through 59 for a AT 5555 n2 or AT500 M2 I only wrote down half the values feel like a idiot I need help will be appreciated