Operating time, respectively, to hit the expected mechanical and electrical In contrast, AM/FM/SSB/RTTY operation would likely To the expected electrical life, we get less than 30 Life of the part after less than 3000 hours of Op/min, which would reach the expected mechanical Of the failures that have happened within the supposedĬonsider this: CW at 20 wpm would generate about 600 Make it more failure prone, which could explain some That far beyond its operational limits would certainly Now weĬan see that those operating QSK CW are overstressing Was simply one of current or voltage overload. We'd all assumed till now that the problem This could account for the varying results encountered in The max internal keyer speed ofĦ7 wpm (as per ARRL review) would yield a brutal 2010 op/sec. Pushes us to about 1000 op/min which is well beyond the relay's rating. 30-40 wpm (what my local CW contesters do) Generate 300 op/min, which is the no-load limit for So, CW at 1 wpm will generateģ0 relay operations per minute. We average 5Ĭharacters per word, 3 dit-dahs per character, and 2 Is 2A, then the answer from February 2002 could make sense.Ĭloser examination of the maximum switching rates reveals a possible problem. "Maximum Carrying Current", but must reduce again prior On, the contact current may rise to as high as the Maximum current at switching time when the contactsĪre opening or closing. It turns out that there are two ways to report maximumĬontact current. The relay specs we have are still not detailed enough. Why has Icom technical support given outĪt least TWO different sets of specs? One theory is that Not match anything we've seen or have been told before.Ĭurious that. Here are a few interesting parameters from the data sheet:įirst we see that the listed current/voltage ratings do It didn't say much, but did showĪ contact current rating of 1A.
Unfortunately, we still did not have many answers.įinally, in February 2002, we found a listing for the OMR-109F (thanks to the kind folks at Omron Electronicsįor helping out). OMR-109 specs are most likely less than these. Relay, which lists a contact rating of 1A 24Vdc orĠ.5 A 120Vac (resistive). More searching did turn up information for the SY-12-K This relay is larger butĬan be squeezed into place. On the PA Connector Board with a SY-12 relay "Replace RL 2 (currently labeled OMR 109) "Larger relay for keying non-ICOM amplifiers" which recommends: There is a Service Bulletin (24287-001A) entitled Searching for "OMR-109" on the Internet did turn up aĬurious tidbit. Is to look up the parts and see what they are rated for.Īs of January, 2002, nobody had revealed any spec sheets None of the answers from tech support have adequatelyĮxplained the odd successes and failures.Īll of this boils down to how much abuse relay RL1271 on While the techs did not agree upon the ratings, theyĭid agree upon using the external relay. Told N1JM that "The real scoop is UP TO 16V OR UP TOĢ amps.", again, recommending an isolation relay. The archives for February 2002 show that tech support While that would explain the failures, it makes some of The true rating was 12 Vdc atĢ0mA and Icom recommended an external isolation relay. See that tech support told AB2BK that there was a In the qth.net Icom reflector archives for January 2000, we So, many of us turned to technical support, but receivedĭifferent answers at different times. That using an isolation relay/circuit seems to prevent
Vs DC loading.ğor years, the topic keeps coming up,īut with no consensus or dependable solution except Hot switching usually get brought up, as well as AC Some talk about bypass capacitors, while others Homebrew explanations of (and solutions for) the problemsĪbound. Note: of the IC-756Pro II instruction manual, Rev.
The ratings in the manual don't tell the full story. Others seem to surviveĬonditions far in excess of that rating. of the instruction manual says that the SEND This continues to be a process of discovery, so I'll On, but since you're still reading, we'll press on. Things get both lengthy and muddy from this point Question that arises is just how much can it handle? Given that the relay is prone to overload, the natural Switching relay, resulting in expensive and/or annoying It is far too easy to overload and damage the internal Specifications as 16V 0.5A - now that's more like it! The IC-756Pro II User Manual,, re-states the SEND relay OMR-109F reed relay or a miniature enclosed relay. This FAQ is also applicable to the IC-7300, IC-756, IC-756Pro, IC-756Pro II,Īnd all other Icom HF transceivers using the Q:3.5.5 Why do I need an external amplifier switching relay? Note
Why do I need an external amplifier keying relay?Įxcerpt from FAQ: Icom IC-746 HF/VHF Transceiver (get PDF version) Coordinator: Dana Hoggatt KB9SSS Copyright (c) 2001, 2002 by Dana Hoggatt, all rights reserved.