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R.I.P. Icom R75?

Joined
Feb 4, 2017
Messages
273
Location
British Columbia, Canada
#1
My second equipment problem in less than a year:

Yesterday morning my R75 was working just fine, until I decided to relocate it to a different part of the room, which was simple enough. I unplugged the power supply, disconnected the antenna, moved the radio to the new location, then reconnected everything. Making sure the power supply was live, I then pressed the receiver's power button ... nothing! Even the backlight didn't come on. When powering up the radio I would usually hear the click of a relay as well, presumably the antenna switcher, but I don't even hear that now.

I've checked the radio's internal fuse, which hasn't blown. The power supply's fuse is intact, as well. Not having a multimeter, I tested the power supply by connecting it to a 3-volt flashlight bulb, expecting it to burn out immediately, which it did.

Has anyone else experienced this, or heard of it happening to an R75? The radio is more than 20 years old, so I suppose a component could have died, but which one, and why it gave out so suddenly, is a complete mystery to me.

Oops! I just noticed that this should have been posted to the equipment forum. Could a moderator please move it for me? Thanks!
 
Last edited:
Joined
Feb 20, 2001
Messages
6,190
#2
Oops! I just noticed that this should have been posted to the equipment forum. Could a moderator please move it for me? Thanks!
You can report your post and ask someone to move it. Mods don't always read every thread
 
Joined
Feb 4, 2017
Messages
273
Location
British Columbia, Canada
#9
Can you power the radio with a different external power supply
I don't have a second external supply. There appears to be nothing wrong with the one I have, and it has been reliable for several years now. The fuse is good, and the supply has overload protection, as well. Nevertheless, when I get a chance I'll go get myself a multitester to double-check the output.
 

iMONITOR

Member
Premium Subscriber
Joined
Sep 20, 2006
Messages
6,324
Location
MACOMB, MI.
#10
Did you used to power it up by tuning the power supply On instead of the radio? I just ran across this from the manual. Could it be this simple? Let us pray...


Front panel
q
POWER SWITCH [POWER]

Push momentarily to turn power ON.
• Turn the optional DC power supply ON in advance.

Push for 2 sec. to turn power OFF
 
Joined
Feb 4, 2017
Messages
273
Location
British Columbia, Canada
#11
Did you used to power it up by tuning the power supply On instead of the radio? I just ran across this from the manual. Could it be this simple? Let us pray...


Front panel
q
POWER SWITCH [POWER]

Push momentarily to turn power ON.
• Turn the optional DC power supply ON in advance.

Push for 2 sec. to turn power OFF
I've always had the power supply on before pressing the power switch. BTW, you needn't bother praying, as it won't help. :)
 

iMONITOR

Member
Premium Subscriber
Joined
Sep 20, 2006
Messages
6,324
Location
MACOMB, MI.
#12
I've always had the power supply on before pressing the power switch. BTW, you needn't bother praying, as it won't help. :)
Sorry it wasn't that simple, never works for me either. Keep us posted on the outcome, good luck, call Icom maybe?
 
Joined
Feb 4, 2017
Messages
273
Location
British Columbia, Canada
#14
My R75 failed to function about five years ago, replaced internal battery and it came back to life.
I checked that, too. Replacing it didn't help. In the past I was able to use the radio with no battery installed. It only affects the clock, which still keeps correct time as long as the radio is connected to a live power supply, even if the radio itself is switched off. The service manual states that applying power automatically disconnects the battery, anyway.
 
Joined
Mar 6, 2005
Messages
573
Location
SE Michigan
#15
It's very possible the relay or the off/on switch went bad if you don't hear the relay click in anymore. Do you have a schematic? Is the relay coil directly connected to the off/on switch?
Is there a bad solder joint or cracked board where the power supply plugs into the receiver? Make sure the power supply has the correct voltage and doesn't bog down under a load(check the voltage after plugging it into the receiver).
Just a couple of simple things to look for while troubleshooting. I don't own a R75 myself.

Jim
 
Last edited:
Joined
Feb 4, 2017
Messages
273
Location
British Columbia, Canada
#16
It's very possible the relay or the off/on switch went bad if you don't hear the relay click in anymore. Do you have a schematic? Is the relay coil directly connected to the off/on switch?
Is there a bad solder joint or cracked board where the power supply plugs into the receiver?
Just a couple of simple things to look for while troubleshooting. I don't own a R75 myself.

Jim
I have the service manual with the schematic, but the only relays that show up are for antenna switching, receive/standby, and the RF attenuator. As for the power switch, it's just a push button that behaves like the power switch on a laptop, i.e. pressing it once activates an electronic switching circuit that turns the radio on, and holding it down makes the circuit shut it off. I think the relay I used to hear was the antenna switch, since the receiver has two antenna inputs, and turning the radio on would have to automatically switch to the antenna that was in use before the radio was shut off. So even with the radio off, power is always applied to the part of the radio that accomplishes this switching function. The schematic is very hard to follow, since so much of it consists of logic circuits, of which I have no understanding at all. The schematic pages in the PDF are so wide that I have to keep scrolling sideways to read them.

This leaves me with two options: 1) I could take the whole thing apart for access to the circuit board and look for bad solder joints, risking damage to the rest of the radio (I'm not good at this sort of thing). 2) I could send the radio to Icom many years beyond the warranty period (I bought it in 1998). That which would cost me a bundle, not only for the repair job, but also for shipping. My Sangean ATS-909X portable is working very well as a backup, and it looks as though it may end up as my main radio. I also have a Sony ICF-2002 that I bought in 1986. It still works like new, but is pretty short on memories (just ten), and its fine tuning control is not very good for tuning SSB signals.
 

iMONITOR

Member
Premium Subscriber
Joined
Sep 20, 2006
Messages
6,324
Location
MACOMB, MI.
#17
Might give these people a call? They're in Canada, eh? :cool:

SERVICES and REPAIRS
ICOM has complete Factory Service facilities located in Delta, British Columbia.

When sending a radio for service to ICOM Canada please complete the Repair Return Form and include this along with your radio for service to:
Service Dept.
ICOM CANADA
Glenwood Centre 150-6165 Hwy 17A
Delta, BC V4K 5B8​
*To open the Repair Return Form (PDF file), Acrobat Reader™ is required. If you have any additional questions please contact our service department via email:
Email: service@icomcanada.com
Fax: (604) 952 0090​
See also:
Technical Bulletins
Instruction Manuals
Discontinued Radio Archives
 
Joined
Apr 1, 2008
Messages
4,458
Location
San Francisco, Ca.
#18
Don't know if anyone already said this but the board mount solder joints for the DC power jack tends to become loose. Try wiggling the line jack (gently) while attempting to engage the power button and see if it catches. I myself have this trouble and have something wedged between the jack board mount and something behind it. Works fine now.
 
Joined
May 28, 2009
Messages
2,604
#19
Even though you were able to burn up a 3v bulb, I'd get a multimeter to check for under-voltage (ie, enough to burn out the bulb, but not high enough to trigger the power-on relay).

Or, if the voltage is good when measured simply at the output of the supply jack, when you actually turn on the radio, the supply can't maintain the load current and just dies.

You may just be looking at a tired old supply that wants to live, but other than being able to burn out a 3v bulb, when real work is being asked of it, it crashes the voltage. Grab a multimeter and see. The good news is that you can adapt the original cable to a new supply.

This is not uncommon for power supplies which spend most of their life being "ON" 24/7 for most of their lives to finally just crap out suddenly when power cycled from a move, etc.
 
Joined
Dec 8, 2017
Messages
176
Location
Naples Florida USA
#20
Herz, I didn't know this about power supplies. Would that mean it's better to unplug receivers when not in use as often times something in the internal circuit is drawing power even when off?

Good luck, GB! Never had an R75 but from what I read it'd be difficult to replace its performance. If you can't find the fault it'd be worth the expense to send it out for repair.
 
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