Removing the front end device was a bit tricky as it seemed to be glued on. Quite a bit of heat was needed to shift it and I would recommend using a heat gun instead of a soldering iron and solder sucker (as I had to do). Still, with care no damage is caused to the board.

The bad news is that Yaesu UK's customer service is pretty much non-existent. I won't be buying another Yaesu rig after experiencing Yaesu UK's "help". I called three times and e-mailed them the same number of times to get no reply weeks on. When I did get through to a human being they told me the SGM2016 device was out of stock and they'd been waiting for 10 weeks to get stock from Japan. To cut a long story short, get spares by contacting Yaesu USA from www.yaesu.com (US Service). They even Air-mailed me two devices completely for FREE so quite why Yaesu UK didn't have the intelligence to do the same was beyond me! Yaesu US gave me fantastic service and I would recommend them to other people suffering the "Yaesu UK customer service blues".

If you do not need "tone call" function and you prefer ACC key doing "BAND CHANGE", you must do small modification inside the transceiver:

1. Remove (disconnect) DC power cable and antenna.
   
    
2. Remove top case (case with speaker).
   
    
3. Locate and remove two SMD resistors R1366 and R1367 (both are zero ohm value), located around the CPU (Q1104).
   
    
4. Put the top cover back, reconnect the DC power and antenna.

I do this mod by myself and worked just fine.

Get the FT-8100R Technical Supplement and follow the instruction on Page 2-11 but set TC4301 / VCV to 3.325 on the VHF VCO. set TC4302 / VCV to 2.0 while Tx'ing (Remember dummy load !!!!)

The VHF VCO is the metal capped "box" with 2 trim holes on the upper print. The TC4302(Tx) is the upper right trim hole. The TC4301(Rx) is the lower right trim hole. The VCV Test Point is the tinn blub just right from the box and just left from the T1008. The VCV for Tx is adjusted while Tx'ing the VCV voltage can range from approx. 0.2 to 8.3 volt (both VHF and UHF) so If you monitor the VCV with a oscilloscope, you can see the change while scanning up/down on the frequency.

Also you will notice that if you use the UHF to receive VHF (V-V), there is big holes on the bands where it does NOT work !

After looking allover the PCB I found that one of the VIA's on the board was glowing in the dark from the minute arcing caused by the intermittent connection, I soldered a link wire from the VIA to the nearest component.. Voila Problem solved.

I e-mailed Yaesu UK, they tell me it is a common fault, so here is a jpg image of what was done to repair the radio.

(most mouse leads will do, the odd ones are missing 1 wire )

• Remove front control panel
  
   
• On the back of the front panel are two screws, remove screws and remove cover
  
   
• On the circuit board, push the flexi-strip connector towards the strip and remove the flexi- strip from the connector.
  
   
• Pull off the volume and squelch plastic knobs, and with a fine screwdriver remove the slotted nut that holds the volume knob in place.
  
   
• Press out the volume knob. It has a small circuit board attached to it, and this will pop off a small connector on the main circuit board. On mine the connector was so poorly soldered to the circuit board that it came off with the volume knob. This was the problem.
  
   
• Re solder the connector to the board and re assemble.

1. Loss of receive audio - even though the 's' meter still shows the radio is receiving OK. There is NO audio at all from the speaker on either band.
   
    
2. When you transmit the transmitter runs virtually no power as the Power Amplifier has no 13.8v feed. You cannot access even very close by repeaters etc.
   
    
3. The transmit fan on the back does not operate when you transmit
   
    
4. The radio may work for a short time when cold. When it heats up there is a 'click' from the speaker and it dies in the way described above quite quickly.

If these are the symptoms you are seeing then solder a wire onto the top PCB as shown in the picture below (you'll need to scratch off the varnish on the tracks to get a good solder connection). Be careful not to short anything else out other than to attach to the tracks shown with the wire. Obviously where I put the bridging wire, those track positions should ALWAYS be connected together by an underside board track (and plated through holes), which you can't see unless you take the whole radio apart. I would not recommend you doing that as you need to be very careful and have a high wattage soldering iron to unsolder some of the earth solder tags.

My radio is 100% perfect now. I can't take any responsibility if you do anything wrong and cause damage. Do this at your own risk. Martin Lynch want 90 pounds to do this repair. Considering it's a 5 minute fix that's an awful lot of money!!

By the way, the 8100 board is a ten layer PCB so try not to heat it up for too long with the soldering iron and this is another reason why I recommend not taking the radio apart. You'll only need to take the top cover off and disconnect the speaker connector to do this repair - NOTHING ELSE. Apparently if you take the board out (not necessary) and bend the PCB you can cause other inner layer fractures. These problems are also common. If the symptoms you are seeing do not match those described - then you may have another track fracture somewhere. The FT8100 is also known for these faults.

However I don't expect you would want to do this mod anyhow.

There must be anyway either a Secret menu or at least 3 Jumpers for setting the country code.

But as usually Software rules, so it is possible to move the lower and upper limits for RX and TX.

With this way the FT8100 will FULL OPEN and can be used on all Frequencies for RX and TX where the Hardware will allow it.

You will get a FREE BAND mod and the good thing is that the ARS will still work.

To make the mod you will need the ADMS 2D Software and a HEX editor.

Or you can download the already patched .RDF file.
It does not matter what Hardware mod you have (or have done) or for witch country your FT8100 is configured.

Technically you are only moving the limits for the Frequency dealing.

Make a .RDF file and edit it with a HEX editor.

The values on the following addresses are defining the lower and upper limits for RX and TX on the VHF and UHF bands

Band      Lower limit adr   Upper Limit adr 
=========================================== 
VHF RX    0A66 and 0B2A     0A6A and 0B2E 
UHF RX    0A76 and 0B8F     0A7A and 0B93 
------------------------------------------- 
VHF TX    0A6E              0A72 
UHF TX    0A7E              0A82 
------------------------------------------- 

Value example: 
-------------- 
VHF RX    0050              0280 
UHF RX    0280              0650 
VHF TX    0050              0280 
UHF TX    0280              0650 

If you insert the values from the example in the abouve addresses, the FT8100 will be opened for RX and TX from 50-280MHz and 280-650MHz.

After modification the following results are mesured.

RESULTS:
Upload: Free.rdf & Stock.tpl

VHF: 

RX 50.00 to 109.995          TX red light active on 80.00 to 109  (not sure if it
                             really TX'ing) 
                             Also all the digits "X" are flashing. 
                             Example:  50.XX to 109.XX 

RX 110.000 to 136.995        Same as above, but has the "AM" 
                             displayed. Also all the digits "X" are flashing. 
                             But this is only between 
                             110.XX to 111.XX  towards the 110.8 MHZ range, the 
                             flashing seems to slow down in "pulse" (not blinking
                             as fast.) 

RX  137.00 to 210.630        Does TX but not tested for RX on a scanner. 

RX  201.630                  the .630 starts to flash. The 201. does not flash. 

RX from 201.63 to 205.995    flashes, however still unknown if it is true   TX. 

RX 206.00 to 280.00          TX but unknown if it is true TX 

UHF: 

RX 280.000 to 550.000        TX light is on, but need to chek for true TX 

RX 551.00 to 650.000         TX light is on, but need to chek for true 
                             TX, also 551.XXXto 650.XXX blinks 

RX 750 to 869.00             NO TX 

When at 750.00 , if you cycle backwards...you end up at 550.00...rotate forware to get to the 600.00MHZ band

RX 894.00 to 1330.00         No TX 

You first need to upload some Mhz, using the 900Mhz range is the easiest. I am using the following in this example:

433.0000 
971.7625  =  871.7625 
971.1375  =  871.1375 
972.4000  =  872.4000 
973.0250  =  873.0250 
973.6625  =  873.6625 
974.2875  =  874.2875 
975.5500  =  875.5500 
976.1750  =  876.1750 
977.4375  =  877.4375 
981.2750  =  881.2750 
981.4875  =  881.4875 

After you get the 900Mhz uploaded to the file, then you are ready to Hex Edit them into 800Mhz as shown on the right.

In the above picture, look for the first Mhz you entered. I searched for 9717 because I was looking for 971.7625 Mhz. The rest of the frequencies you need to change are just a few spaces off. Compare the picture below with the Mhz files from above. All you need to do is change the 9 into an 8.

You will see all the changes I made in RED. The second number does not get changed, but turns RED due to the fact that they are in pairs. Also the Red dots on the far right of the pic is automatically changed when you chang the number into an 8.

Upload the file into your 8100R radio & you should have the Frequencies in the Cell band in your radio.

1. First you have to build and interface cable to communicate PC and transceiver.

   The schema tested and working is the next one.

   

   For the 6 mini DIN connector you can use a PS2 prologator or the cable from an old PS2 mouse.

                                  

   The pins you have to connect are GROUND and PKS.

2. Second you have to make a memory dump with ADMS software. Is not a free one but you can find looking on Internet. Elsewhere you can buy it at RT systems shopping website.
3. Later once you have the template, you have to edit with an hexadecimal editing tool as for example Hex Workshop 4.2. Its shareware so you can use it and test it for 30 days. I hope you late less time : - )
4. The info as original came from is:

                  RX lower limit  RX upper limit   TX lower limit TX upper limit
   -----------------------------------------------------------------------------
   UHF at adr:0630H     2A B9 80        C6 5D 40         41 9C E0       44 AA 20
                       (2800000)       (13000000)       (4300000)      (4500000)
    
   VHF at adr:0730H     10 C8 E0        2A B9 80         15 F9 00       16 95 40
                       (1100000)       (2800000)        (1440000)      (1480000)
   -----------------------------------------------------------------------------
   

5. You have to modify this address positions as:

   At adress 0636H change from 419CE044AA20 to 2AB980C65D40 for UHF, and at adress 0736H change from 15F900169540 to 10C8E02AB980 for VHF.

   This will open TX from 137 to 180. And in UHF from 420 to 480. Other cases don`t put power on antena.

6. Download the templates I captured, the original one and modified one.

Its posible to have problems on uploading when using other OS that is not Windows 98. The unic solution i found was use Windows 98. It Works Ok on this Os. On Windows XP downloading info from transceiver is Ok but uploading no Works.