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  #1 (permalink)  
Old 03-03-2015, 7:32 AM
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Default iCom IC-R7000 problem

I have an old IC-R7000 that is working but I have to hit the power button 10 or 15 times for it to power up,and all so when it comes on after about 10 to 15 min.'s it will start a very high pitch squalling sound ,almost to high for human ears .its not coming from the speaker but some where from the back side of the radio ,its not very loud and the radio seems to work other wise.any idea of what it may be ? 

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Old 03-19-2015, 8:20 AM
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Does this happen when using the AC power supply or with 12VDC? If you can try the other other power source this might eliminate one common problem with these radios.

As these radios age certain components start to fail. Most commonly it is electrolytic capacitors, they tend to dry out after 15-20 years or so. There are various sellers of capacitor kits for the R7000 and R71's but the project is not for the feint of heart. I tried it once and it was not pretty. I have a friend doing it now on another radio (R71) and it has been a real experience...
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Old 03-20-2015, 2:06 AM
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Would be willing to bet a power supply or DC-DC converter problem and something is becoming unlocked.

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Old 03-20-2015, 6:01 AM
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Yes, the R7000 power supply contains a DC-DC converter section that provides the -7v, -12v and +24V rails.

In equipment of this vintage it is likely that Electrolytic capacitors are starting to get tired or leaky, which can cause the power supply to fail as it gets warm - and the power supply in these things does get very warm
DC-DC converters are very susceptible to faulty caps.

I would be replacing all the electrolytic caps in the power supply. It is time consuming, but not hard or costly.
All circuits in these old radios use simple 'through board' construction. Just make sure the replacement caps are of the same capacitance value and at least the same working voltage (a little higher if possible).

And make a note of where everything goes when you pull it apart!

Good luck..
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Old 03-20-2015, 6:04 AM
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Also, the service manual for these is pretty easy to find online too.
Google is your friend (unless you believe that it is actually run by the NSA and it is tracking your every move).
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Old 03-20-2015, 8:49 AM
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mods.dk - Articles for Icom 'IC-R7000'
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Old 03-24-2015, 10:17 AM
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I think a better solution is to run the radio off of its DC connector (either on the rear panel or hiding behind the panel). These radios (I own 3) are known for heat build-up and the power supply failure. Before you go to the work of replacing the caps, try powering it up with a good 13,8 vdc power supply and see how things work. I only power my radios (R-700's & R-9000's) with this method and they run cool 24 hours a day, really extends the component life. Hope this helps you out
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Old 03-24-2015, 2:21 PM
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I concur with running off a separate 12VDC supply if possible, especially if it turns out to be the AC supply is faulty.

When I had a pair of R7000's and an R71 I did this and the radios ran cool all day long.
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Old 03-24-2015, 4:45 PM
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Granted, running these radios from an external 12V supply does reduce the heat build up in the power supply area, but the AC-12V power supply section in these radios is pretty robust and doesn't usually fail (if it does, it is usually catastrophic, not intermittent like the OP's).

Even when running from an external 12V DC supply, the separate internal DC-DC converter section still operates to provide the +, - and +24V rails, so Isolating the mains to 12V DC power supply section is unlikely to be the answer if the problem is in this area - highly likely given the symptoms.

Sounds to me like the damage has already been done and that DC-DC converter section will need to be reworked regardless.
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Old 03-25-2015, 7:59 AM
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sorry guys I should have mentioned it is already on a 12 volt power supply
I have never used the AC power cord with this radio as I had been informed of the AC problems when I got it .
every thing seems to be working alright other wises
sometime I can Liston to the radio for 30 min.'s or so before it starts the high pitch squeal
the sound is sometimes louder then other times.
thanks for all the reply guys
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Old 03-25-2015, 2:40 PM
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The "high pitched squeal" may be electrolytic capacitors that have dried out. I would look at the audio stage, especially the speaker amp, bypass caps first.
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Old 03-26-2015, 1:41 PM
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Quote:
Originally Posted by cmdrwill View Post
The "high pitched squeal" may be electrolytic capacitors that have dried out. I would look at the audio stage, especially the speaker amp, bypass caps first.
The PLL reference oscillator superimposes a 5 kHz audio artifact because of leakage. You may want to check the service manual, section 4-1-22, as it deals with the notch filtering.

The DC : DC converters will work regardless of whether the receiver is plugged into the wall and the power is coming through the REG unit (the internal power supply) or running 12 VDC, so other symptoms may persist.

Last edited by 902; 03-26-2015 at 2:13 PM..
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Old 03-26-2015, 3:39 PM
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In case you haven't found this already ......

I had to do the Service Bulletin, and the Display Board changes, years ago on my two IC-R7000's

Rich

Bulletin #:.. 13889-015
Date:.. April 1, 1988
Subject:.. If display fails to operate at power on

DC-DC Board Location




DC-DC Board




Display Board




Display Board (cropped)

Attached Files
File Type: txt R7000.TXT (5.1 KB, 227 views)
File Type: txt Display_Problem.txt (29.4 KB, 351 views)

Last edited by rbm; 03-26-2015 at 3:55 PM..
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Old 01-06-2018, 11:40 AM
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Default Noise from dc to dc unit

I have been gifted a non working r-7000, I was able to bring it back to life by replacing the c19 and c20 electrolytic caps. The memory backup battery needed replacement. It also had the high pitched squeal mentioned in this thread. The noise was coming from the dc to dc power supply. I finally found that the transformer was the source of the noise. When I pressed on it the noise stopped. By touching it I could make the noise come and go. I re-soldered the contacts but this made no change. The fix (temporary or permanent ??) was to put a piece of plastic (I used tube from a spray duster) between the transformer and the shield next to it. I suspect the transformer core or perhaps a winding has loosened with age and was resonating with the square wave on contact 6 or 10. I have a spare DC to DC converter and will replace the whole unit if the problem returns.

I hope this post might be of interest to the group.
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Old 01-10-2018, 8:47 AM
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Quote:
Originally Posted by ghkennedy View Post
I have been gifted a non working r-7000, I was able to bring it back to life by replacing the c19 and c20 electrolytic caps. The memory backup battery needed replacement. It also had the high pitched squeal mentioned in this thread. The noise was coming from the dc to dc power supply. I finally found that the transformer was the source of the noise. When I pressed on it the noise stopped. By touching it I could make the noise come and go. I re-soldered the contacts but this made no change. The fix (temporary or permanent ??) was to put a piece of plastic (I used tube from a spray duster) between the transformer and the shield next to it. I suspect the transformer core or perhaps a winding has loosened with age and was resonating with the square wave on contact 6 or 10. I have a spare DC to DC converter and will replace the whole unit if the problem returns.

I hope this post might be of interest to the group.
I re-capped my R7000 about 6 months ago, possibly for the 4th, maybe 5th time. My recommendation is that if those two electrolytics needed to be replaced, others in the radio may also need replacement. I do this prophylactically to maintain performance.

At this point, I may also need to realign mine, and troubleshoot what I feel is a decrease in sensitivity. I'm in an area where there is primarily 800 MHz use and little of anything else, so that perceived sensitivity thing bugs me even more.

All the best, and welcome to RR! Hope to be reading your contributions!
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Old 03-15-2018, 5:21 AM
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I would be replacing all the electrolytic caps in the power supply. It is time consuming, but not hard or costly.
All circuits in these old radios use simple 'through board' construction. Just make sure new horse racing betting sites
 the replacement caps are of the same capacitance value and at least the same working voltage
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Old 03-15-2018, 7:08 AM
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Quote:
Originally Posted by 902 View Post
I re-capped my R7000 about 6 months ago, possibly for the 4th, maybe 5th time. My recommendation is that if those two electrolytics needed to be replaced, others in the radio may also need replacement. I do this prophylactically to maintain performance.

At this point, I may also need to realign mine, and troubleshoot what I feel is a decrease in sensitivity. I'm in an area where there is primarily 800 MHz use and little of anything else, so that perceived sensitivity thing bugs me even more.

All the best, and welcome to RR! Hope to be reading your contributions!
As heat if a villain in the electrolytic life, when I owned a couple R7000, I always used an external (Astron) power supply and things were fine after that. The R7000 were eventually replaced by more recent ICOM models.
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Old 03-15-2018, 8:58 PM
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The ICR-7000 is a great performing radio that will still bring $350 on the used market. Fixing it is a good investment. I sold mine to a friend some 20+ years ago when I upgraded to an ICR-9000. He called me last month to say the power transformer had given up. I helped him select a comparable toroidial transformer from Hammond to install. He did so, the part was about $45 and guess what? No more overheating power supply. Apparently the original transformers ran pretty hot. So for about $45 you can keep your internal 13.8 VDC power supply and fix the heat. Search for my name and ICR-7000 and you will find the thread somewhere on the interwebs. So I would say a good recapping and new transformer and those radios could live to be 60.

Just a note, anytime you are working on the internal 13.8V power supply, be sure to keep a load resistor on it to draw about 150 ma. The regulator if unloaded is designed such that the output will creep up to 18 or 19VDC with no load. Not a bug, its a feature of a bootstrap resistor across the pass transistor. First time I did this, reconnecting the radio it got a short pulse of 18 volts and blew the meter lamp. You live and learn.
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Last edited by RFI-EMI-GUY; 03-15-2018 at 9:09 PM..
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Old 03-15-2018, 9:03 PM
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Quote:
Originally Posted by 902 View Post
I re-capped my R7000 about 6 months ago, possibly for the 4th, maybe 5th time. My recommendation is that if those two electrolytics needed to be replaced, others in the radio may also need replacement. I do this prophylactically to maintain performance.

At this point, I may also need to realign mine, and troubleshoot what I feel is a decrease in sensitivity. I'm in an area where there is primarily 800 MHz use and little of anything else, so that perceived sensitivity thing bugs me even more.

All the best, and welcome to RR! Hope to be reading your contributions!
There was a bulletin regarding power supply ripple and front end varactor tuning. Assuming the receiver PS is recapped, there is another consideration.

There is track tuning (Varactor) in the receiver front end which tracks the VCO steering line voltage. So you have to make sure the VCO is tuned properly for each band and then touch up each front end filter section. It is this complexity that makes it a great receiver.
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Old 05-03-2018, 5:27 PM
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Question Professional Help

I too have a mostly dead R-7000. I do not have the expertise to work on the innards myself. Are there any shops that work on these things?
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