During Sukarnos time, the army, navy and airforce, as well as the police were all armed by the soviets. Aid from soviet blok countries also meant that many industrial plants, factories and workshops were also built and equipped with soviet tools and equipement. With the US backed overthrow of Sukarno and installation of Suharto, the US then ensured that Indonesia was armed by them. Much of that equipement is now well and truly outdated, some units still have M1 carbines in use, so Indonesia seeking out new weapon deals is more of a practical matter than a matter for concern, but obviously the current security threats do also play a part. Given the way the US has been a fair weather friend to Indonesia over the years, there would be some reluctance to rely on them solely for their armaments, there is always the danger that once you become dependent on the US, they have a tendency to pull the rug out from under you, however I think that it is more of a matter of many countries having an underlying suspicion of too much US influence in the region, so by Indonesia going to Russia for it provides more of a balance. However it probably comes down to getting value for money and expanding trade opportunities for Indonesia.,
