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This is the second time, fuse on the irlp board blown off on 5 volt input

kd1yh
 

This is the second time, fuse on the irlp board blown off on 5 volt input.
 
Does anybody have a clue why this  happens?
 
The node was stating a cor on issue, and  upon further investing found the fuse  destroyed , burnt board etc.
 
Paul Upham
KD1YH
node 8571

David Cameron - IRLP
 

Are you 100% sure that it's only 5 volt input? Some people accidentally send 12 volt, and that is the result.

Dave Cameron 

-------- Original message --------
From: kd1yh <kd1yh@...>
Date: 7/22/20 6:26 PM (GMT-08:00)
To: IRLP@irlp.groups.io
Subject: [IRLP] This is the second time, fuse on the irlp board blown off on 5 volt input

This is the second time, fuse on the irlp board blown off on 5 volt input.
 
Does anybody have a clue why this  happens?
 
The node was stating a cor on issue, and  upon further investing found the fuse  destroyed , burnt board etc.
 
Paul Upham
KD1YH
node 8571

Ramon Gandia
 

On 7/22/20 5:26 PM, kd1yh wrote:
This is the second time, fuse on the irlp board blown off on 5 volt input.
Does anybody have a clue why this  happens?
The node was stating a cor on issue, and  upon further investing found
the fuse  destroyed , burnt board etc.
Paul Upham
KD1YH
node 8571
One time, in 1965, solid state stereo players were new. Nobody knew how
to fix them.

My girlfriend then (an old woman now), had this one that would not work.
Kept blowing a soldered in fuse.

I couldn't see the problem. Stages were DC coupled too.

So, I put a piece of #12 wire in place of that fuse.

In short order, the bad parts identified themselves, and I fixed it.
Then I soldered the 3AG fuse back in.

Sounds to me like a driver transistor for the PTT has gone bad.
You could try to fix it; open up a connection here and there. Good
luck getting the schematic. But its not too bad to sorta trace it.

Or, you could do my "Smoke Detector" troubleshooting ...

Or, you can buy a new board. Nothing lasts forever.

If you gots a variable power supply, bring up the volts slowly and poke
around with your DVM. Good luck without a schematic.

For $350, Dave C might fix yours.

--
Ramon AL7X 3288 3289 7254
Nome, Alaska USA

kd1yh
 

It was built and running since 2017 in this computer. HP 5730,
what size fuse and tvs is it?
Paul Upham
KD1YH node 8571
 

From: David Cameron - IRLP
Sent: Wednesday, July 22, 2020 10:15 PM
To: IRLP@irlp.groups.io
Subject: Re: [IRLP] This is the second time, fuse on the irlp board blown off on 5 volt input
 
Are you 100% sure that it's only 5 volt input? Some people accidentally send 12 volt, and that is the result.
 
Dave Cameron
 
-------- Original message --------
From: kd1yh <kd1yh@...>
Date: 7/22/20 6:26 PM (GMT-08:00)
To: IRLP@irlp.groups.io
Subject: [IRLP] This is the second time, fuse on the irlp board blown off on 5 volt input
 
This is the second time, fuse on the irlp board blown off on 5 volt input.
 
Does anybody have a clue why this  happens?
 
The node was stating a cor on issue, and  upon further investing found the fuse  destroyed , burnt board etc.
 
Paul Upham
KD1YH
node 8571

David Cameron - IRLP
 

It's a 200ma polyfuse and the tvs is 5.7v.

I'd measure the voltage on the red wire that feeds the board. If that polyfuse is getting that hot, there is a short somewhere or the voltage is going over 5.7v

Dave Cameron 

-------- Original message --------
From: kd1yh <kd1yh@...>
Date: 7/23/20 3:34 AM (GMT-08:00)
To: IRLP@irlp.groups.io
Subject: Re: [IRLP] This is the second time, fuse on the irlp board blown off on 5 volt input

It was built and running since 2017 in this computer. HP 5730,
what size fuse and tvs is it?
Paul Upham
KD1YH node 8571
 
From: David Cameron - IRLP
Sent: Wednesday, July 22, 2020 10:15 PM
To: IRLP@irlp.groups.io
Subject: Re: [IRLP] This is the second time, fuse on the irlp board blown off on 5 volt input
 
Are you 100% sure that it's only 5 volt input? Some people accidentally send 12 volt, and that is the result.
 
Dave Cameron
 
-------- Original message --------
From: kd1yh <kd1yh@...>
Date: 7/22/20 6:26 PM (GMT-08:00)
To: IRLP@irlp.groups.io
Subject: [IRLP] This is the second time, fuse on the irlp board blown off on 5 volt input
 
This is the second time, fuse on the irlp board blown off on 5 volt input.
 
Does anybody have a clue why this  happens?
 
The node was stating a cor on issue, and  upon further investing found the fuse  destroyed , burnt board etc.
 
Paul Upham
KD1YH
node 8571

kd1yh
 

That make sense, need replacement
Paul Upham
KD1YH
node 8581
 

From: David Cameron - IRLP
Sent: Thursday, July 23, 2020 2:00 PM
To: IRLP@irlp.groups.io
Subject: Re: [IRLP] This is the second time, fuse on the irlp board blown off on 5 volt input
 
It's a 200ma polyfuse and the tvs is 5.7v.
 
I'd measure the voltage on the red wire that feeds the board. If that polyfuse is getting that hot, there is a short somewhere or the voltage is going over 5.7v
 
Dave Cameron
 
-------- Original message --------
From: kd1yh <kd1yh@...>
Date: 7/23/20 3:34 AM (GMT-08:00)
To: IRLP@irlp.groups.io
Subject: Re: [IRLP] This is the second time, fuse on the irlp board blown off on 5 volt input
 
It was built and running since 2017 in this computer. HP 5730,
what size fuse and tvs is it?
Paul Upham
KD1YH node 8571
 
From: David Cameron - IRLP
Sent: Wednesday, July 22, 2020 10:15 PM
To: IRLP@irlp.groups.io
Subject: Re: [IRLP] This is the second time, fuse on the irlp board blown off on 5 volt input
 
Are you 100% sure that it's only 5 volt input? Some people accidentally send 12 volt, and that is the result.
 
Dave Cameron
 
-------- Original message --------
From: kd1yh <kd1yh@...>
Date: 7/22/20 6:26 PM (GMT-08:00)
To: IRLP@irlp.groups.io
Subject: [IRLP] This is the second time, fuse on the irlp board blown off on 5 volt input
 
This is the second time, fuse on the irlp board blown off on 5 volt input.
 
Does anybody have a clue why this  happens?
 
The node was stating a cor on issue, and  upon further investing found the fuse  destroyed , burnt board etc.
 
Paul Upham
KD1YH
node 8571