Tuesday, February 2, 2016

ICOM IC-7100 low SSB power modification

Hi guys.

I hope this will end problems with IC-7100 low SSB power. Because ICOM did not recognizes the problem, and we know there's a problem as always solution is bring by HAM RADIO community.

This is not my mod, and this is not official ICOM mod in any way.

WARNING ! ! !

NO ANY PERSON MENTIONED BELOW SHOULD BE TREATED GUILTY IF YOU DO SOMETHING WRONG AND DAMAGE YOUR RADIO.
THIS IS INTERNAL HARDWARE MODIFICATION, SO ALL WHAT YOU DO, IS YOUR OWN RESPONSIBILTY.


My sincere regards to my Greek friend Manos SV7GBR for support, and OM Jorge PY3CC for sharing the mod with us.

and finally BIG KUDOS for Mr.Marios SV0CL for great job with the mod.

Let's go: Remove all screws to get to the bottom of main unit and locate part of our interest:


According to SV0CL there are two steps we can perform to get more SSB power:

FIRST mod - "SOFT" - simple jumper added at point labelled "1" on picture below. You can use 0 Ohm SMD resistor as well soldered right to the ground plane. This should double total SSB power.

Schematic diagram MAIN UNIT, lower right corner, page 10-5 in Service Manual.


PCB look - Main Unit, bottom side, Service Manual, page 7-4.


Closer look - mod " 1 " point.


You can solder jumper in this place, or do it my way - 0Ohm SMD 0805 resistor.
Scratch small point of ground just behind the parallel capacitors:


Gently solder the resistor both sides - one to ground, another to capacitors :


This is end of mod "1 "

===================================================================

SECOND mod - "HARD" - should give full power on SSB, labelled " 2 " - 10uFd capacitor added across R1522 slightly below mod " 1 " with positive "+" leg attached to R1523. According to Jorge PY3CC this capacitor is Tantalum one, but looking at schematic diagram, any good quality 10uFd will do the job.

Closer look - mod " 2 " point


Prepare 10uFd capacitor, standard or tantalum. According to legs You can do it your own way. This is how I did it :


Positive leg is soldered between R1522 and R1523, negative is soldered to R1519 ground side.

Another look :


Secure the capacitor with small amount of nail enamel ( ask your XYL ) or any other silcone glue to prevent mechanical stresses when in mobile.


This is end of mod " 2 ". Assembly the 7100 cover and enjoy.
Perfomed with my own radio S/N 03001722.

Again big thanks to SV0CL, SV7GBR, and PY3CC for sharing the "know how"

73 !






12 comments:

  1. Szanowni użytkownicy... Na początek wielki szacun i wielkie podziękowania dla Grzegorza SP3RNZ. Mało w dzisiejszych czasach jest taki osób. Pełen profesjonalista.
    Do rzeczy MOD w 100% u mnie za działał. Pierwszą część wykonałem w oparciu o drucik KEYLIIGHT (czy jakoś tak) do najbliższego punktu masowego, prawdopodobnie od ekranu. Drugą część modyfikacji wykonałem w oparciu o kondensator 10uF/63V z prostego powodu nie miałem innego. Plus pomiędzy zaznaczone przez Grzegorza rezystory natomiast minus do najbliższego punktu masowego-także ekranu. Po włączeniu super moc - i pełne 100W.
    Jedna ale to jedyna uwaga... Ze względu na wielkość elementów SMD nie polecam wykonywania tej modyfikacji osobom które nie mają pewnej ręki...Pewną rękę ma Grzegorz i do niego można się bez problemu zgłaszać po modyfikację.
    Grzegorz ja Ci jeszcze raz szczerze bardzo dziękuję!!!
    Przemek SP9KN

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  2. Unfortunately, my English is very poor, but I have to say that described by Gregory modification works 100%.
    Warning of very small components. If you do not have proper soldering give your radio to someone who knows how to do it. For example Grzegorz SP3RNZ

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  3. No to fajnie że w końcu dostałeś cynk. Po za tym że działa, patrzę na schemat ... chm pogadamy bo mod jest "ciekawy" elektronicznie. SP3UCA

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  4. I performed this mod yesterday, in addition with replacing a resistor (R148, connected to IC141 Page 10-3 Service manual) to increase the microphone gain a bit to get a bit better usage of the mic. gain. I have now full power with normal voice with mic.gain set @ 50%. I would like to know if it is ok that i publish this modifications at mods.dk. Off course i will mention the original publishers... pa7fa (at) amsat.org. Regards!

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    Replies
    1. BTW, i changed R148 to 2k7 to increase the audio output of IC141.

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    2. What is the value of the resistor the you replaced from R148 ?
      My name is George N2OWE.
      I would like to get this straight If I wanted the best Mod would I only do MOD # 2 only? That is to use the capacitor described above only and not do MOD # 1 at the same time?

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  5. Is there any consequence if i only did mod 1

    Mods 2 little hard for me.

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  6. Hi Gents
    As I understood 1 step will increase SSB power twice, Please let me know if is it enough for normal operation or both steps are important? Can I use for jumper simple wire?

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  7. @Richard - Care to share the diagram and resistor type you used for the Mic Gain mod. Thanks!

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  8. "Soft Mod" performed last week, totally transformed my output and drives the amp nice now. Great article.
    M0XAL

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  9. Any one now a shop that does this mod ??

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  10. Zrobiłem mod ze zworką i tylko z nią. Poprawa jest bardzo duża. Teraz jest tak jak trzeba. Ale... zawsze jest coś. Przy mik gain 35% comp 5 włączonej lub nie i zjechaniu mocą do np. 50% widać niepokojące szpilki mocy do 100%. Dość częste. Przy podłączeniu PA może to prawdopodobnie uszkodzić wzmacniacz. W FM widać przy pełnej mocy lekkie oscylacje wskaźnika mocy i wskaźnika prądu. To dość niefajne. Dowołać się łatwiej ale... Co z tym ale :D?

    ReplyDelete