Intermitten tx


Mike
 

Ok, so I thought I had a mic issue, no tx when I press the button, grabbed mic from another icom vhf seemed to work fine a few months. Fast forward now, no tx on any mic. Can tune auto tuner fine, so I know the radio can tx. If you press the mic a million times sometimes it goes into tx. Other times when it does it imminently shuts off. I'm at a loss with this one. 


Max
 

Have you tried it into a dummy load? That is what I would try first, just to make sure you don't have an RF problem. And the 7000 has two mike jacks, one on the control head and one on the back of the main radio. Try them both.

Max KG4PID


On Friday, June 25, 2021, 09:00:07 PM CDT, mforsythe@... <mforsythe@...> wrote:


Ok, so I thought I had a mic issue, no tx when I press the button, grabbed mic from another icom vhf seemed to work fine a few months. Fast forward now, no tx on any mic. Can tune auto tuner fine, so I know the radio can tx. If you press the mic a million times sometimes it goes into tx. Other times when it does it imminently shuts off. I'm at a loss with this one. 


Paul Hansen
 

Have you tried both mic jacks?

 

Thank You

 

Paul W. Hansen, W6XA

Amateur Radio Service

2134 Carthage Road

Tucker, GA 30084

(864) 222-3539

www.amateurradioservice.com

 

From: ic7000@groups.io [mailto:ic7000@groups.io] On Behalf Of mforsythe@...
Sent: Friday, June 25, 2021 21:58
To: ic7000@groups.io
Subject: [ic7000] Intermitten tx

 

Ok, so I thought I had a mic issue, no tx when I press the button, grabbed mic from another icom vhf seemed to work fine a few months. Fast forward now, no tx on any mic. Can tune auto tuner fine, so I know the radio can tx. If you press the mic a million times sometimes it goes into tx. Other times when it does it imminently shuts off. I'm at a loss with this one. 


James KB7TBT
 

Very common issue is the momentary switch inside the mic fails..

If you open the mic and press the button hard it should TX.

Lots of folks that do the mic mod replace the switch as well..

(I have the OEM mic that has failed in a box)

73

James - KB7TBT

On 6/25/21 6:57 PM, mforsythe@gmail.com wrote:
Ok, so I thought I had a mic issue, no tx when I press the button, grabbed mic from another icom vhf seemed to work fine a few months. Fast forward now, no tx on any mic. Can tune auto tuner fine, so I know the radio can tx. If you press the mic a million times sometimes it goes into tx. Other times when it does it imminently shuts off. I'm at a loss with this one.


Steve W3AHL
 

The original PTT switch used in the HM-151 mic'swas not sealed and had a cheap actuator design.  Icom started shipping a better sealed switch for repair parts in 2007 I think.  It was an ALPS SKQJLBA010, available from Mouser.com, although it is currently backordered, but they have SKQJLAA010 in stock, which is identical except with a black instead of gray actuator stem.

https://www.mouser.com/ProductDetail/Alps-Alpine/SKQJLAA010?qs=%2Fha2pyFaduiNCIVDxt%252BQU%2F5bP%252BmBGtzmFC3u3iEdhgc%3D

The switch is easy to replace, however it is important to observe the manufacturer's soldering instructions, available in the datasheet on Mouser's web site at the link above.  It specifies a maximum soldering iron tip temperature of 350 degrees C, using no more than a 20 watt iron applied for a maximum of 3 seconds to each lead.  Exceeding these limits can cause the aluminum snap disk inside the switch to oxidize and cause premature failure or intermittent operation.

Since the old switch is not sealed it can often be "repaired" temporarily by squirting a good quality contact cleaner such as Deoxit 5 into the switch and repeatedly pushing the plunger to help clean the oxidation.  However, the switch should be replaced soon after it is cleaned.  The new switches are sealed and cannot be cleaned.

Steve, W3AHL


Mike
 

I tried back mic jack....very weird...works better but only if I turn vox on... I am really confused by the issue and if it is hardware of software related, I didn't have time to torture shoot too much I will tonight. If vox is off it seems to not be in tx although now I get the led on the mic.... 


On Sat, Jun 26, 2021, 10:48 AM Steve W3AHL <w3ahl@...> wrote:
The original PTT switch used in the HM-151 mic'swas not sealed and had a cheap actuator design.  Icom started shipping a better sealed switch for repair parts in 2007 I think.  It was an ALPS SKQJLBA010, available from Mouser.com, although it is currently backordered, but they have SKQJLAA010 in stock, which is identical except with a black instead of gray actuator stem.

https://www.mouser.com/ProductDetail/Alps-Alpine/SKQJLAA010?qs=%2Fha2pyFaduiNCIVDxt%252BQU%2F5bP%252BmBGtzmFC3u3iEdhgc%3D

The switch is easy to replace, however it is important to observe the manufacturer's soldering instructions, available in the datasheet on Mouser's web site at the link above.  It specifies a maximum soldering iron tip temperature of 350 degrees C, using no more than a 20 watt iron applied for a maximum of 3 seconds to each lead.  Exceeding these limits can cause the aluminum snap disk inside the switch to oxidize and cause premature failure or intermittent operation.

Since the old switch is not sealed it can often be "repaired" temporarily by squirting a good quality contact cleaner such as Deoxit 5 into the switch and repeatedly pushing the plunger to help clean the oxidation.  However, the switch should be replaced soon after it is cleaned.  The new switches are sealed and cannot be cleaned.

Steve, W3AHL


Linda C
 

Steve W3AHL,
I’ve been following this thread because I’ve had the same problem with a used IC7000 I bought several years ago. I bought a replacement mic (off of eBay, which was probably stupid) just to find it had the exact same issue. I think now that maybe it was one of the original faulty ones that Icom pulled. Who knows.

I’m looking forward to trying the fix you’re talking about as soon as I can replace the antennas a tornado got.

Thanks for the info and thanks to all for the thread

73,
Linda AG5HJ

On Jun 26, 2021, at 9:48 AM, Steve W3AHL <w3ahl@att.net> wrote:

SKQJLAA010


VK3SQ - Geoff
 

Thanks Steve for that information and link, a great help.

73 de Geoff vk3sq


Michael Forsythe
 

OK... some progress....

after opening up and looking for voltage drop in tx it turns out i had a bad fuse holder in the power cable.... and although the same mic can key my icom vhf into TX over and over, it does not work on the IC7000. i crimped some wire into a RJ45 and touched TX to ground and it works every time, seems issues were external to radio. 


Robert Blackburn
 

As long as the 7000 had been around everyone needs to know that the original fuses and fuse holders are notorious for causing transmit problems.


On Jul 27, 2021, at 18:59, Michael Forsythe <mike@...> wrote:

OK... some progress....

after opening up and looking for voltage drop in tx it turns out i had a bad fuse holder in the power cable.... and although the same mic can key my icom vhf into TX over and over, it does not work on the IC7000. i crimped some wire into a RJ45 and touched TX to ground and it works every time, seems issues were external to radio. 


Steve W3AHL
 

The original ATC style fuse holders from the factory have an inherent design flaw.  The contacts do not scrape through the surface oxidation on the fuse blade (like typical holders do), which results in increased temperature at the contact junction.  Usually you can see a dark line forming on the fuse blade.  Cleaning the contacts and fuse blade will help for a few weeks or months, depending on your environment, TX duty cycle, etc.  

The best solution is to replace the fuse holders with an automotive style ATC holder with #10 AWG pigtails rated for 40 amp fuses.  Don't use the more readily available holders with #12 wire pigtails found in many automotive parts stores.  Here's a good quality waterproof holder that I've used for years:

https://www.delcity.net/store/Waterproof-Circuit-Breaker-&-Fuse-Holders/p_913669.h_913671

Use the first item in the list, part # 79110.  Del City has no minimum order and ships same or next day typically.

The other option is to use a RigRunner PowerPole distribution block.  For mobile installations a fuse in the radio's DC- lead is still needed.  But for mobile power wiring you should minimize the number of fuses and non-soldered connections to reduce the IR drop at higher currents.  Since there should be a DC+ fuse at the battery, if you used a RigRunner already, it is best to not have a redundant fuse in the radio's power cable for DC+.  A fuse in the DC- lead in the engine compartment is not recommended -- it should be near the radio.

Steve, W3AHL


 

Similarly, some of the microswitches in the mic PTT were notorious for going bad.  Fortunately, replacements are readily available (I found them for $1 at the local electronics store), and replacing the microswitch will restore PTT operation.  The operation can be a little fiddly, but otherwise straightforward.

On 28/7/21 11:33 am, Robert Blackburn via groups.io wrote:
As long as the 7000 had been around everyone needs to know that the original fuses and fuse holders are notorious for causing transmit problems.


On Jul 27, 2021, at 18:59, Michael Forsythe <mike@...> wrote:

OK... some progress....

after opening up and looking for voltage drop in tx it turns out i had a bad fuse holder in the power cable.... and although the same mic can key my icom vhf into TX over and over, it does not work on the IC7000. i crimped some wire into a RJ45 and touched TX to ground and it works every time, seems issues were external to radio. 


-- 
73 de Tony VK3JED/VK3IRL
http://vkradio.com


Charles & Sandra Cohen
 

FWIW --

I was on a sailboat for three years, with an IC-706, on the Pacific Coast, in warm water.  The IC-706 had the dreaded glass fuses in its power cord -- much more trouble-prone than ATC fuses.

I spritzed the fuse contacts, at the start of the voyage, with Boeshield T-9 -- a mixture of anti-corrosion ingredients and wax:

 . . . They never gave any trouble.

I got into the habit of spraying it on _every_ connector, before plugging it in, or tightening a screw on it.  Slightly gooey, but very, very effective.

Boeshield T-9 is cheap and not hard to find.  

.     Charles / va7cpc