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  1. Yaesu-FRG-7
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FRG-7 lock light problem

 

Hi there.?

My friend very kindly gave my his old FRG-7. It works really well and I love it!

It has one problem. The lock Led will not work, unless the radio was turned off and sitting for a few hours.?
Then, the led will work but only very dimly. The led will continue getting dimmer and after a few minutes it will simply stop working.?
The actual bulb is fine, I know this because when powering up the radio, it will light up for less than a second at full brightness.

It's a strange problem. It seems like as the radio warms, up the led stops working.?

Other than that, everything works fine!?

I will appreciate any help, and I thank you in advance.?
 

Hi, sounds exactly like a bad solder joint. Probably at the pcb end. If your handy with a soldering iron, it should be an easy fix.? Hope this helps.?

Bob


On Wed, Aug 3, 2022 at 8:03 PM, yitzimarks@...
<yitzimarks@...> wrote:
Hi there.?

My friend very kindly gave my his old FRG-7. It works really well and I love it!

It has one problem. The lock Led will not work, unless the radio was turned off and sitting for a few hours.?
Then, the led will work but only very dimly. The led will continue getting dimmer and after a few minutes it will simply stop working.?
The actual bulb is fine, I know this because when powering up the radio, it will light up for less than a second at full brightness.

It's a strange problem. It seems like as the radio warms, up the led stops working.?

Other than that, everything works fine!?

I will appreciate any help, and I thank you in advance.?
 

But why would it get worse when the radio is on?
I checked all the joints, they look fine.?
 

It gets worse because when the radio is on it heats up. The bad joint opens because of Thermal expantion. It might not be the wire for the Led, it could be any of the transistors, resistors, etc associated with the Led operation.?

Bob


On Thu, Aug 4, 2022 at 5:41 AM, yitzimarks@...
<yitzimarks@...> wrote:
But why would it get worse when the radio is on?
I checked all the joints, they look fine.?

 

Thanks for the explanation.?

Last night I tested the voltage at the joint of the led wire. It was 1.45v when the led was working (fist time starting the radio after letting it sit for a few hours) then it dropped slowly all the way to 0v.

I tried to trace the what the led is connected to on the circuit board but it got a little bit confusing.

If I post a high resolution picture of the circuit board, will you be able to spot a bad joint??
 

Hi, just go through the area with a soldering iron and reflow all the connections. The main components that control the Led are Q110 and Q111, plus the surrounding resistors and capacitors. I assume you have a schematic diagram.?


On Thu, Aug 4, 2022 at 9:00 AM, yitzimarks@...
<yitzimarks@...> wrote:
Thanks for the explanation.?

Last night I tested the voltage at the joint of the led wire. It was 1.45v when the led was working (fist time starting the radio after letting it sit for a few hours) then it dropped slowly all the way to 0v.

I tried to trace the what the led is connected to on the circuit board but it got a little bit confusing.

If I post a high resolution picture of the circuit board, will you be able to spot a bad joint??

 

I have noticed that the lock light in my FRG-7 dims with humidity. I doubt this is the problem that yitzimarks@... is observing, but I toss this observation in to see if anyone else has seen that issue and resolved it.

-- Gary KD1TE

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