Getting Kenwood audio receiver to power on

Thread Starter

DragonTheta

Joined Feb 6, 2022
85
Hi

The Kenwood KR - V5570 was working great until it was left outside for a few months in a covered area with a roof but open to the air. Now it won't power on. What should I start to check

I think it's about a 20 or so year old receiver
 

Tonyr1084

Joined Sep 24, 2015
6,884
First most obvious check is to see if the fuse has blown. Before we go any further let's verify that the fuse is good.

If it's blown you could try replacing it - but that might cause other issues. If the fuse is blown and you put a new fuse in and it also blows then there's something more we need to do. But we'll get there when the time comes.
 

MrSalts

Joined Apr 2, 2020
1,762
If you can look at the bottom through the air vents, check for any white or blue/green oxidation of the main PCB. Humidity from industrial areas (acidic) and salt spray (if you are near the sea) can really cause PCBs to corrode.

look at the vent areas at the top of each cylinder capacitor to see if the vents have ruptured or corroded.

Also, is it not working and no LEDs or are some LEDs lighting up but no sound?
 

Tonyr1084

Joined Sep 24, 2015
6,884
It would appear that any fuses will be inside the unit. Likely it's going to be something that is considered "Not User Serviceable" (NUS). Meaning it generally takes a technician to work on the unit. However, just because it's NUS that doesn't mean you can't work on it yourself.

This is a photograph of a power distribution board that came out of a scrap Sanyo Stereo. The glass device in the center, marked (upside down) F12 is a fuse. The white plug at the bottom left corner is where the power cord plugged into the distribution board. The distribution board consists of a multi-tapped transformer, the fuse and a few passive components on the other side. They're not germane to our discussion. However, the fuse you're going to be looking for is likely going to be a glass fuse. But not necessarily a glass fuse. Whatever type of fuse you have it's going to be marked (commonly) with the letter F which designates a fuse. Mine can be snapped out of the holder and replaced.
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I also have a Radio Shack power amplifier. It has a fuse that can be removed from the back and replaced. Some equipment has user serviceable components such as fuses, others don't.

If you can locate and identify the main fuse then you should be able to test it. MAKE SURE THE UNIT IS UNPLUGGED before servicing. Safety is the first and foremost concern.

With the fuse removed, check it for continuity using a volt meter of some sort. Set it to ohms and check it. The reading should be near to zero ohms. You're going to see some low resistance readings, that's usually just the resistance of the test leads and should be of no consequential concern. If you test it and it shows OL then the fuse is blown. When replacing the fuse replace it with one of the SAME EXACT VALUE. Putting in the wrong value can cause harm.

If the new fuse immediately burns out then there's other issues that need to be tracked down. If your skill level is low you may want to find someone local who can help you. Or you'll need to find a servicing store where you can have an expert find and fix the problem. Chances are if you know enough you can probably do the work yourself.

My Radio Shack amp blew the main fuse. It blew because of a shorted bridge rectifier. I was able to identify the fault by disconnecting things and applying power. When I plugged the rectifier back in it blew the fuse. Removing the rectifier and bench testing it revealed a shorted leg, which is why the fuse was blowing. I replaced the rectifier and have been happily enjoying my amp for years now. Yes, you can find and fix the problem - IF you know a little about what you're doing. Too little and you run the chance of blowing out something more expensive, or even harming yourself. So proceed accordingly.
 

Thread Starter

DragonTheta

Joined Feb 6, 2022
85
Thank you

I found the fuse and took it out. I looked in the voltmeter instructions and found something that said the buzzer test. So I set it to that and I assumed that is the continuity test. The voltmeter beeped pretty much the whole time that I had it touching the fuse on both sides. And the reading on the screen was going between 0.0 and 0.5
 

ThePanMan

Joined Mar 13, 2020
367
I'd say the fuse is good. But there may be other fuses. Don't ask me where. If you have the make and model, see if you can find a schematic diagram on line. That'd be the place I'd go next.
 

MisterBill2

Joined Jan 23, 2018
11,877
Left outside for a few months means that dirt, moisture and insects can easiy be probems, and aso corrosion of switches, including contacts. So after a serious inspection, cean al of the switches. Is the unit totally dead or just not working right. If totay dead check for insects in the mains power loop.
 
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Tonyr1084

Joined Sep 24, 2015
6,884
Yes, like Pan said, the fuse is good. Something else is bothering it. Bill suggested a thorough cleaning. That can be helpful too. My wife deep cleaned the microwave oven and it stopped working. The problem was that she used too much cleaner and ended up washing grease down inside the unit and all over the control board. She thought it was a lost cause. I took the board out and washed it using soap and water. Then alcohol to dry off the water. Then a blast of compressed air to do a final drying and it works to this day. They say a microwave oven is good for about 5 years. We've had this one for a good 10 and we use it almost every day.

Yeah, I think a good cleaning is in order. Also, we need to know more specifically what it does and doesn't do. Can you describe in more detail what happens?
 

Thread Starter

DragonTheta

Joined Feb 6, 2022
85
Okay I can give it a clean out. Maybe I can brush it out. I don't know how exactly to clean it. It was under cover so it should have only been dust getting into it, besides moisture which probably got in also.

As far as its functionality, when I have it plugged in and I press the power button nothing at all happens. No lights come on, nothing at all.
 

MisterBill2

Joined Jan 23, 2018
11,877
"Stone dead" points toward the power circuit primary side. So do a resistance check across the power plug pins first. The problem might be really simple. With the switch "ON" the resistance should be less than 1000 ohms., or even less than 100 ohms.
 

ThePanMan

Joined Mar 13, 2020
367
Excellent point Bill. But what if it's powered from a remote? If it doesn't have an actual switch? Does it have a power switch? Or an "ON" button? Some units are always powered but in sleep mode. When you press the button it comes on.
 

MisterBill2

Joined Jan 23, 2018
11,877
The TS has not mentioned any remote.Then it gets complicated. And I have not come across an amp or receiver with remote ON/OFF, although there may be such. Waiting for the TS response.
But even with remote, the resistance check should reveal something.
 

Tonyr1084

Joined Sep 24, 2015
6,884
Ah. I see where Pan's going with this: I have some old stereo's that are always ready to switch on. The push of the power button doesn't actually apply 120VAC to the power board, it takes power from the power board and distributes it to the components. They're those energy hogs that are always consuming power all the time, even when "Off" (or actually in sleep mode - - - low current draw). But I see your point @MisterBill2. If the main power board is down then nothing will happen.
 

Tonyr1084

Joined Sep 24, 2015
6,884
How do I check the power plug pins
Still not certain of how your stereo powers on. Nevertheless, one test you can do is test for resistance across the two prongs of the plug. If your stereo has three prongs, ignore the round one, it's just a safety ground. Test for resistance. If you get a reading - report your findings. If you get an OL (Open or Over Limit) push the power button. Test with the meter set to ohms or resistance (both are the same thing). Report your findings.

Quick question on the power button, does it push in and stay in? Or does it pop back out after you've pushed it? If it pops out then it's probably not controlling the main power. Rather, it likely wakes the stereo up as opposed to turning it ON.

Can you provide a picture of the power switch / button?

Can't access your link. Would require I set up an account and sign in.
 

MisterBill2

Joined Jan 23, 2018
11,877
Yes, you should be measuring the resistance between the two line cord plug pins. With the button in, (for on) there should be a resistance reading. This is totaly safe to do because the receiver must be unplugged to do the check. To make sure that it is measuring resistance, also touch the two probes to each other and observe that you get a very low reading, less than 5 ohms.
 

Thread Starter

DragonTheta

Joined Feb 6, 2022
85
Thank you

Okay I put it into what I am not sure if it was resistance measuring or the buzzer test. It showed one symbol that means the buzzer test and one symbol that means the resistance measuring or I think it also means ohms.

When I touched the points to each other it buzzed and the number on the screen was like 0.2 or 3 or 5 or a couple times it was above 5 but it was mostly below 5.

When I touched the points to the power plugs on the receiver it did absolutely nothing.

The power button is always in the same place. It does not click in and out.
 

MisterBill2

Joined Jan 23, 2018
11,877
Thank you

Okay I put it into what I am not sure if it was resistance measuring or the buzzer test. It showed one symbol that means the buzzer test and one symbol that means the resistance measuring or I think it also means ohms.

When I touched the points to each other it buzzed and the number on the screen was like 0.2 or 3 or 5 or a couple times it was above 5 but it was mostly below 5.

When I touched the points to the power plugs on the receiver it did absolutely nothing.

The power button is always in the same place. It does not click in and out.
OK, so the resistance does not switch to some low value. Now you need to do that same test with the meter set to measure resistance in ohms.
BUT FIRST another simple check, if you can access the terminals of the main power switch. Connect one of the meter probes to both flat pins of the power plug, not the round ground pin. Then probe the terminals on the power switch. At some point there should be some reading less than the open circuit reading, unless the receiver has only remote control of the power function.
Also, check for some connection between the power plug and the fuse on the power circuit board. At least one of the pins on the board should connect to the fuse.
One more question: does the power board, have on it, or connected to it, a transformer?? Most stereo receivers of the older vintage have a power transformer. That will be a good clue as to what we are dealing with.
 
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