R8500 Loses Memory

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pittsville

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I have an Icom R8500 that I bought used. It worked fine for several years, but now it loses all of it's frequencies that are entered into memory whenever I turn it off.

Also the radio was unblocked when I bought it. I don't know if is an early model that was restored, or if it came unblocked from the factory. In relation to this, when the radio loses it's frequencies it also becomes a blocked model! I can restore full coverage by performing the reset, but it goes back to being blocked when it loses it's memory.

I don't think this model has an internal battery for memory backup. From what I've read it's supposed to be non-volatile, which I think means it doesn't have a battery. I'm into the top of the radio and I don't see one. I might pull the bottom cover off and look in there to see if it has one.

I took the top off to see if I could spot any leaking or bulged capacitors but I don't see any. I noticed it looks like there's been some heat coming from the cluster of capacitors that are near where the power supply plugs into the radio. I suppose one of them might be bad. The radio also sort of pops (from the speaker) when I power it on. I can't remember if it always did that or not, but I think I remember reading that the pop could mean a bad capacitor.

I have a couple of other radios that need to be sent to Icom for repair so I'll probably add this one to the list, but I was wondering if anyone else ever experienced this problem, and what it might be?
 

N4UMJ

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Wow ...never seen that problem before and I have serviced over a dozen R8500's for various problems.

There is a power down reset associated with the Microprocessor that is supposed to place the CPU in an off state when you power down. I think a capacitor or two holds the charge long enough to do a standard power down sequence even if you yank the power cord out abruptly.

I see an EEPROM on the main board and one on the Front panel. I think the one on the front panel stores your memories and the one on the main board stores the Alignment data and such. The country code is setup by a diode matrix and should not change at will.....unless the modifier (assuming its modified) did not properly solder the additional components and therefore the CPU resets when the matrix appears to be changed. Or its in a non standard configuration which might tell the CPU to start over again from the start. Who knows there?

All this has to do with the firmware from ICOM and I must say very little of this is covered in the service manual. The country codes and diode matrix configurations are in the service manual.

I've never changed an eeprom either and I think there is an intialization (data load) for that that maybe ICOM can only do. Always wondered about that with the PCR100 and PCR1000's I've worked on.

Sounds like I would look at the resistors associated with the mod (if its been done) and make sure they are setup properly. That would for sure cause a reset (CPU reset and channel loss) when the CPU sees something is different but why yours does it every time is a mystery.

My most recent repairs on the older PCR100's with many years of usage are showing deteriorated caps causing some interesting symptoms. So your idea of looking at the area with a source of heat (Power supply/regulator area) is sound.

Let us know the outcome & Good Luck. ICOM in Bellevue does do some fantastic service work in my experiences,

Ed
N4UMJ
 

pittsville

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I'm not very good at radio repair

Ed,

Thanks for your response.

Whatever is wrong with this radio is most likely beyond the scope of my ability to fix it, other than doing some kind of reset. I have tried the reset which sets the radio back to the way it came from the factory, and doing that is what will restore full 800 coverage, but it never lasts.

I will look up the 800 mod for the radio and then check to see if it looks like someone was doing some work in that area. My son used to work with soldering SMD components, so I'm going to try to have him here when I look at it. He has better eyes than I do, and would know more about what to look for.

I also have a 756 Pro that has no audio for quite a while when first turned on, then for no apparent reason it starts working, The last time I tried it, it never did make any sound for a long, long time. I tried the headphone jack and there's no sound there. I'm planning to send that one into the shop for repair sometime, along with my 2720H.

The 2720 won't turn on. I can see the display backlight flickering real fast, but the display won't come on. I think the radio is working other than not having a working display. I can hear static when I open the squelch. That problem started when I tried to fix the modular cord that connects the display to the main unit. When I got the radio, the insulation was not inside the modular plug all the way and I could see the wires. It bothered me. All I did was lift up the thing that crushes down on the insulation and holds it into the plug, and streteched the insulation a little to get it back in the plug again and crimped it. I ordered a new cable from Universal but that didn't help.

Thanks again for your ideas and suggestions.

Andy
 

pittsville

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I just saw this problem on eBay

Apparently someone else is having a similar problem. This is from an eBay listing for an R8500:

"When I got it I discovered that the radio had a habit of erasing the memory banks every so often at power up. I sent it back to Icom for a check up and to have the problem repaired. While Icom was able to bring the radio to up full specification in every aspect of RF performance they were unable to resolve the memory problem at a reasonable cost.For what its worth, I have never been able to discern any reason or regularity to the memory erasure problem. Sometime it seems like I can go months without a problem. Other times it will happen a couple times a week, again only at power up! "

It would be interesting to know what Icom told the person, as far as what would be required to fix the memory, and the cost, but he didn't put that in the listing...
 

ka3jjz

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While it's not an elegant choice, you might want to dump your memories to a PC; then if you lose them, it should be little effort to restore things back the way you want it.

There are several programs that boast R8500 support, and they are linked in the associated pages;

Receiver Software Applications - The RadioReference Wiki

Bonito Radiocom
Ergo
Scancat
Syslabs Radioctl
tk8500
some Signal Intelligence Products

Amateur Radio Transceiver Control - The RadioReference Wiki

Commander
Ham Radio Deluxe
TRX Manager

73 Mike
 

XDX

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I have just bought a new Icom 8500, if you can say new in the box, several months ago and the radio does not make a poping sound from the speaker when it comes on , but I was sure that I red there was a back up power supply for short power outages,but I am no pro with this, I do know they run to flippin hot and a small fan with a filter should be running on it all the time , or after it warms up. CHEERS!!!!
 
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bagmouse7

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I have seen this happen to my 8500 as well.
I have owned it for almost 10 years and it has performed perfectly (it is a great radio).
However, about 3 years ago it began to loose it's memory, and over a period of about 6 months it must have lost it 4 or 5 times. Then, just as suddenly as it started, it stopped happening. It has now kept it's memory for about 3 years now with no problems.
I am not sure what happened and I did not do anything to fix it.
Weird...
 
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