Dick
That just confirms the value of this Forum! A U.K. dealer says mics are no longer available but, as you say, they are all over eBay. And affordable too. I will get one ordered up and hope for the best. I’m now determined to get it working by hook or by crook.
Simon

Hi Simon,
Mics (Hm 180) that are compatible for the 710 seem to be fairly easily available here in the US. Mics do break (actually, it is the wiring connections that usually give way: I always try to figure some sort of strain relief before the terminal connections, both to the transceiver and the mic), but with the amount of down time your unit has, I would still be betting on a corroded terminal or something similar.
Use google US for details on the Hm180 as the 710s are far less common in marine Europe. It will be the pin configuration that will be most important. ICOM is usually quite responsive to inquiries, so you might call them.
I know also people who are likely to have access to equipment. I could bring/leave a mic in Lewisporte and if we share an anchorage and we can do some trouble-shooting and some comm during the coming season.
And, yes, it would be great to get it working as SSB comm really solidifies the cruising community on this side of the pond and is far far more functionally useful than any maritime use of SSB in Northern Europe or the Med.
My best, Dick

Thanks both for you input and Dick thanks for your's off line. Interesting that there are previously repoorted failures of the Mic. I heard back today from Yacht.com who say they can no longer get replacement mics as the plug was more or less unique to that model and is obsolete. I think I need to be a bit more systematic in my fault finding next time I'm on the boat and see if I can check out the continuity of the various Mic connections and repair if required. I've got a meter for measuring aerial output too and, as Dick says, I need to check the ATU which I had actually forgotten all about! It would be great to get it working for N America and beyond! I will let you know how I get on.
Simon

On second thought, 6 amps should make for about 150 watts at 24v. D

BTW Hasbun,
I would guess that 8a is about right for a 24v system as the max power draw for the M-710 is about 150 watts (as I believe all marine SSBs must have for max TX).
My best, Dick

Good advice, Hasbun,
Many battery monitoring systems are not up to the task of reading battery v with enough accuracy and, as you clarify, without averaging. I guess I was thinking of a good digital VOM for this job (and for the continuity/shorts inspections), although keying the mic with an analog meter should make it jump.
My best, Dick

On our 24v boat, full power transmission is evidenced by about an 8A draw. Should be more, but it is what it is.

Dick's advice regarding using power consumption as an indicator of transmission activity is true and tried, but look at this little anecdote: we have two battery monitoring systems. One old and original to the boat, and one the latest and greatest from Mastervolt. Very fancy. Well, the Mastervolt is nearly useless to determine SSB transmission consumption, because instead of giving an instant reading to the second, it seems to report a trend of power consumption over the past five seconds or so. So only the old and "obsolete" power meter is good for checking the radio.

The microphone on our M-710 was found to be broken in 2014. The little wire at the base of the microphone wore off, like a cheap microphone. Which it is! I think the replacement was only $25 or so. It's been fine since.

Cheers,

Hi Simon,
The M-710 is a fine SSB, almost bulletproof, but, of course, without the bells and whistles of modern technology, all of which, at my last review, I felt I could do without: hence, I still use my 710.
10 years is a long time, so a few hours spent checking and cleaning every connection and making sure of all continuity and ensuring no shorts will be well worth the effort. It takes very little to interfere with SSB operation.
How do you know you are not TXing? Were you trying it on the hard?
First, chk to see you should see if the 710 is set to TX on high power. If so, you should see a significant voltage drop when the PTT button is depressed on any reasonably sized cruising battery bank.
If not, the mic is likely still good and I would move next to the tuner cable. If you hear a click of the tuner (what tuner do you have) when you change frequencies (say 12 megs to an 8 meg channel) when you depress the PTT button, that is a good sign.
There is a start. I will think on more.
Good luck, Dick Stevenson, s/v Alchemy

We have a 19 year old icom m-710 which we haven’t used for ten years. Having now exited European waters we switched it on and it is receiving fine. The power supply is good but when we press the PTT button on the fist microphone nothing happens. I’m not sure if this is a problem with the mic or with the set and wondered if there is anyone able advise? Do fist mics fail? If it’s a set problem is there anything simple I can check?
Simon

Here is the information on the KISS-SSB Ground / Counterpoise. http://www.kiss-ssb.com/ It sounds very good indeed. Thanks for the heads up, Bill.

Vice Commodore, OCC