I was looking for a IC-R100 for many years. I was lucky enough to find one earlier this month on a local ad. It wasn’t cheap but I know they are getting harder to find as time goes by. It came with no accessories but the seller advertised it as ”working perfectly fine”. After getting a 12V adapter I fired it up - the display looks great and audio is fine. AM for airband and WFM are working as expected but narrow FM doesn’t show any sign of a signal on any frequency. Also the squelch only functions when the radio is first turned on. As soon as it’s done receiving a signal it breaks the squelch and the control knob seems to have no effect. I also wanted to use the R100 for shortwave but in my first couple of experiments I picked up only 2 stations around 5900 kHz and they were very weak and had a lot of background noise. I found an owners manual, it really doesn’t provide anything that was helpful in resolving this radio’s shortcoming. So to begin with does anyone know why narrow FM mode will not engage? I can listen to VHF/UHF stations with WFM but they don’t sound right and the lack of squelch is downright annoying.
Used IC-R100 missing narrow FM mode
- Thread starter SatHunter
- Start date
Whiskey3JMC
DXpeditioner, RRDB & Google-fu ninja 4 hire
Something probably needs an alignment or a component is failing or has failed.
I don't remember of the R100 had it's operating and tuning parameters stored in the radio's eeprom or not like the slightly newer R1000's do but if so and yours lost that data, that could explain the poor or no reception.
What are you using for an antenna? A scanner antennas probably not going to get much on the HF (shortwave) bands below 30 MHz.
And as @Whiskey3JMC noted, the R100 did not have a narrow FM mode but you should still hear signals across the V/UHF bands regardless. The audio may sound low volume as most all signals use a narrower bandwidth today but like I said, you should still hear something.
What happens if you manually tune it to 162.xxx (your local NOAA WX channel) in FM mode? Any signal at all?
I don't remember of the R100 had it's operating and tuning parameters stored in the radio's eeprom or not like the slightly newer R1000's do but if so and yours lost that data, that could explain the poor or no reception.
What are you using for an antenna? A scanner antennas probably not going to get much on the HF (shortwave) bands below 30 MHz.
And as @Whiskey3JMC noted, the R100 did not have a narrow FM mode but you should still hear signals across the V/UHF bands regardless. The audio may sound low volume as most all signals use a narrower bandwidth today but like I said, you should still hear something.
What happens if you manually tune it to 162.xxx (your local NOAA WX channel) in FM mode? Any signal at all?
Whiskey3JMC
DXpeditioner, RRDB & Google-fu ninja 4 hire
Correct, OP will need a loop antenna or long wire antenna depending on their RF environment for optimal SWLing. See here
When I first turned on the radio I immediately tried weather on 162.55 and it comes in fine on WFM with a very strong signal. When I switch to FM mode there in no signal at all and no sound coming out of the speaker. I also tried local amateur radio frequencies on 146 to 148 MHZ and had zero signal as well.
As far as antennas I have an array of different dipoles, 45’ and 70’ long wires and a variety of indoor antennas. Shortwave is working fine on my Yaesu, Kenwoods, Tecsuns and Radio Shack models. I’m not sure if Icom models had a eeprom that a user could reprogram. This is my first Icom. I always heard good things about them. I’m confident that this isn’t a performance problem but rather a component failure. The previous owner may not have been aware of these shortcomings as it appears that he had cellular frequencies programmed into the radio and they may have worked fine for him.
Thank you for the link. I always enjoy trying out new antenna projects. Lots of interference here in the downtown area. Three emergency service transmitter facilities within blocks on my home. So the FM mode on the Icom isn’t narrow FM? Do you know how Icom designates it and which bands it would be used for. I may never get to experiment with it if I can’t get the radio repaired or reset.
It does sound like something failed in the regular FM bandwidth stage. Possibly an IF crystal filter or something in the FM IF stage.
No idea if new crystal filters can be found for the IF stage if that's even the problem.
I'm almost positive there's a full service manual online, you may be able to trace out and fix the problem yourself if you are handy with this type of repair. Look for parts of circuits that have the WFM mode not used on the schematic.
I'd assume the R100 or PCR100 use a lot of surface mounted components which can make repairing hard if you don't have thr correct tools but it's still not impossible to do so.
They were neat radios and if I had one with the same problem or any problem really, I'd sure attempt a repair!
When tuning your NOAA WX frequency on 162.550, what happens when you select AM for the mode? Can you still hear the audio from 162.55 even though it will be distorted?
If so, that may also help in tracing out the problem component or part of the circuit that's bad.
I wish I had the skills to repair it but unfortunately my training ended with fixing tube and some transistor circuits in the early 80’s. The weather channel at 162.550 mhz comes in at full strength in AM mode. I can easily hear the distorted broadcast. I tried FM again and everything goes quiet and the signal totally disappears. AM mode also works fine on air between 118 and 125 mhz but again there is no squelch. I just tried broadcast band and it’s not picking up much either. Even the 2 strongest local stations barely come in. On my other radios I pick up at least 2 dozen stations between 540 and 1500 kHz even in the daytime. I’m anxious to give the R100 another try at shortwave, that’s mainly what I bought this radio for.
Thanks for your assistance- I think I found a link online with the schematic and service manual. The problem would be trying to find someone around here to repair it.
MTS2000des
5B2_BEE00 Czar
Late 90's/early 2000 leaky electrolytic caps. Bet that board has capacitor piss all over it if not a bad IF filer as others stated. An alignment is the least of this radio's issues.
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What is called "FM" (15 kHz) in the user manual was sometimes called "NFM" at the time as the NFM of today did not yet exist. That mode, 15 kHz FM, should work for NOAA radio etc. and to some extent for the narrower FM of today (weakly receiving such). The fact that he hears nothing indicates either he has the squelch on and set too high or something is wrong with the radio.
bearcatrp
Member
Looks like a nice receiver. Old but nice. Now if Icom could make another like this and have the R30 guts, I would be all over it!
I really appreciate your response. In the back of my mind I was thinking the caps might have blown. With that in mind I’ll try taking the lid off the radio and have a look tomorrow. I’ve seen the kits available online recently so I’d definitely want to get that fixed. I must have done the capacitor replacement on at least a dozen General Instrument satellite receivers through the years.
As far as IF filters - are they replaceable? I wonder if Icom still has replacement parts for these older models.
Unfortunately the squelch control seems to have no effect, I tried using contact cleaner on it with no change. The shaft seems to be very loose & has no resistance at all. The on/off volume switch feels a lot different and performs as expected. The seller has disappeared so there is no way to verify his experience with the receiver.
I found the kit online - 54 electrolytics. Would they all need to be replaced or just the faulty ones?
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Yep, bad caps also came to mind. That era radio is probably full of them like you said.
I have several radios made in those days and swapping out the old caps with new was always one of the first things I'd do.
Ha! Replacing 54 caps would be tiresome for me with my old eyes!
Knowing which to replace could be tricky as well but I'd start with all of them installed in any power supply stages. Then try to identify the stages used for the modes that don't work and replace those. If things start working okay, you can chose to do the others or keep them handy for a future time when others may fail.
If the kit is cheap enough in cost and you do plan on keeping the radio, it's probably a good idea to buy the kit as one day the sizes used may no longer be available from reputable sources and you may be limited to purchasing them from Chinese supplier that has falsely marked what they sell.
Of course the radio could have other failed components like a bad IC or two so swapping out the caps may not fix things.
Thanks for all of the great tips! My eyes and soldering skills have both gone south. If I identify a cap problem I’ll attempt to fix the minimum and see if it makes a difference. Beyond that I have many other very capable receivers for almost every band. I just always wanted to own an Icom. They never sold them here, only Kenwood and Yaesu. I may keep it because it’s such a cool looking radio or possibly sell it for what I paid and let someone else try to restore it or use it for parts if they happen to own another one
So I found the time to pop the bottom off of the R100. The only casualty of the incident was the bottom mounted speaker coming unplugged. The circuit board looks exceptionally clean (not what I expected). It looks a thousand times better than a $300 unit I bid on from Belgium on an auction site. So now the problem becomes more complex. I’ve attached an image to this post. Hoping to find a local radio amateur with exceptional eyesight that might be able to help me troubleshoot this baby
From time to time I use my 3rd hand which has a magnifying glass on it with two alligator clips. Makes a big difference when mount over a circuit to work on. I've tried those 'goofy' looking magnifier glass and they worked well, but I didn't needed them at that time. Things have change...
54 caps to replace is a challenge, but I would go for broke if you have the complete set. You never know which one is the faulty one and likely a few working in concert are wrecking the experience. Replace them over several days and before you know it you are done!
Good Luck!
Mike
54 caps to replace is a challenge, but I would go for broke if you have the complete set. You never know which one is the faulty one and likely a few working in concert are wrecking the experience. Replace them over several days and before you know it you are done!
Good Luck!
Mike
You might also try unplugging and re-plugging all the internal connectors throughout the entire radio now that you have it open.
RFI-EMI-GUY
Member
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If the receiver is basically working, except for the narrow FM mode, it is unlikely replacing 54 capacitors will get you success.
I would suggest that the problem is an IF crystal like the two cans on the left with orange dots or the blue plastic cubes. Having the schematic and board layout would help identify which of these are for NFM vs WFM. Then the troubleshooting becomes easy. Get a disc capacitor like .05 uF or so, cut the leads to about 1/4 inch and glue it to a plastic stick. Then short out the outer leads of the IF crystals or ungrounded leads of the square filters and see if the squelch circuit suddenly behaves. Then solder the cap in that spot and test the radio. You will still need a replacement crystal to get proper bandwidth, but those are readily available. The problem could be elswhere in the logic that switches the IF chain, but more likley the crystal wore out or broke from the radio being dropped.
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