This IC, and this is reason why I start to search where is problem. From IC 74X production start I replaced about 20 Through legs!!!!! And this was by ICOM absolutely underestimated, beside minimalĪrea of copper with dense area of connecting hole about 6cm sq. Producer of this IC uPC1678 in application note describe, how big mustīe minimal area of copper on PCB for good cooling. Higher current and also higher temperature. IC has idling current aboutĥ0mA and produce heat in receive regime. Power also in receive state, which main mistake is. And components on static electricity path are still
ICOM IC 756 PRO II AND G5RV ANTENNA DRIVER
S/N 3300, they add this diodes in factory.īUT I had on my table IC746PRO S/N 3422 with factory installed these diodesĪnd driver IC was DEAD. Where they recommend add diodes to input of HF receiver. ICOM company stays on idea, that this driver ICįailed only by static electricity from HF antenna (in this case other twoĬapacitors and two diodes must be destroyed, but these components are afterĭestruction of this driver IC still heath) and even they released service note, This is draft mistake, which ICOMĬompany don’t want to accept. »Very common failure of device IC 746 746PRO, 756, 756PRO and 7400 isĭestruction IC uPC1678 (driver for PA). I have stolen the below comments from where Karel, OK1DNH writes: ESD protection is a real pain in any electronic device.ġ00% carrier type signals or not the problem will most likely show up no Any non ESD protected device is always more sensitive to an ESD hit, whether Retrofit policy if rigs are returned for repair, ESD related or not. When it comes to a fix for the ESD ICOM seems to have taken the issue into a In some cases this may be one week later orĮven later. That is an even more plausible cause and in my case seen as a slow degradation.īut when ESD does happen it, probably, shows as instant death, i.e. Not believe that ESD has anything to do with over heating It might be that ESD can kill the IC151, over night and completely, but I do You can see a schematic of my station set-up here. Sequence controller to manage the switching sequence in order not to switchĪnything with HF on it. Thirdly, I have aħ0 MHz transverter permanently connected to the ANT 1. Located under the roof, furthermore do I hardly ever use HF. Very little chance that ESD is the reason in my case since my HF antennas are Numbering principle has been changed sometime during 2003, starting with 02#, seven digits,Īnd should also have the anti ESD fix from the factory.įirstly, my IC-746PRO has S/N 3623 and the TX has failed. Comments are indicating that the ESD originates from HF antenna. Removed the page, take a look here how itīe OK from the factory. According to ICOMĪmerica S/N after 3550 (if URL fails which I think it does or ICOM has (re-)installing a few anti Electro Static Discharge components. Roomers are that ICOM says that it is no longer a problem after FM or digital, just made it easier to see. It all seems to relate to one single component: IC151, µPC1678G, P/Nĩ1213606, and overheating.
I already knew of the Dead TX issue of the IC-746PRO and it seemed It was RF feedback but why now? I had not rearranged my shack or cabling. Transmitted 100% carrier type signals, e.g. Started to drop in power, rapid drops though, and only visible when I Dead TX (IC151 RF Unit)Īfter having been the owner of an IC-746PRO for a good six months (August Please note that I no longer own an ICOM IC-746PRO and I have not investigated any other problems than the three problems described below. I have experienced all three generic faults: IC151 dead, ALC Jumping and LCD power supply failure. If you are the owner of either the ICOM IC-746PRO or the IC-7400 you may already have experienced the issues. The purpose of this web page is to try to investigate some of the issues around ICOM IC-746PRO reported by many radio amateurs through out the world and unfortunately not properly taken care of by ICOM.
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