All,
Had a client give me one of these things that did a quiet fade out to 'no operation' status.
Got it home, plugged in, and nada.
It did not light up.
Opened the case and did some casual poking.
The main power is a small compact switch mode unit.
In this case 120 vac in and 13.8 out.
The 120 side worked, the 13.8 gave me a big fat zero reading.
Took the PSU out and opened the case.
Looked cooked which is to be expected in a unit this old.
Did not find anything too bad.
Undid some screws and took the board out.
Grabbed the ever trusty ESR meter and went to work.
Four caps were bad.
220uF (>30 ohms)
56uF (5 or more for the rest)
1uF
and a .47uF
Subbed in exact when I could, and 'near enough' values where I did not have stock.
Re applied power and the unit lit up and worked.
Cool.
Put the cover back on, re install in the radio.
Turn it on, and nothing.
Here we go again, check the input, ok, and nothing on the output.
Tap on the cage cover and bang, sputter.
Yank the plug out.
Pull the unit out again.
Seems the land cracked under the 120vac input wire, and that shorted to the case.
Glass brush the solder mask, solder the wires to the lands.
Clean with solvent.
Glass brush the soot and spatter.
Plug it back in, ok, still working.
Re install it in the radio.
Still working.
Going to let it cook over lunch.
Will post photos later.
On a 'back up' computer and have some issues in that area.
Be well all.
Jack Crow
Had a client give me one of these things that did a quiet fade out to 'no operation' status.
Got it home, plugged in, and nada.
It did not light up.
Opened the case and did some casual poking.
The main power is a small compact switch mode unit.
In this case 120 vac in and 13.8 out.
The 120 side worked, the 13.8 gave me a big fat zero reading.
Took the PSU out and opened the case.
Looked cooked which is to be expected in a unit this old.
Did not find anything too bad.
Undid some screws and took the board out.
Grabbed the ever trusty ESR meter and went to work.
Four caps were bad.
220uF (>30 ohms)
56uF (5 or more for the rest)
1uF
and a .47uF
Subbed in exact when I could, and 'near enough' values where I did not have stock.
Re applied power and the unit lit up and worked.
Cool.
Put the cover back on, re install in the radio.
Turn it on, and nothing.
Here we go again, check the input, ok, and nothing on the output.
Tap on the cage cover and bang, sputter.
Yank the plug out.
Pull the unit out again.
Seems the land cracked under the 120vac input wire, and that shorted to the case.
Glass brush the solder mask, solder the wires to the lands.
Clean with solvent.
Glass brush the soot and spatter.
Plug it back in, ok, still working.
Re install it in the radio.
Still working.
Going to let it cook over lunch.
Will post photos later.
On a 'back up' computer and have some issues in that area.
Be well all.
Jack Crow
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