Cobra 138xlr squelch
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perrym1962
- Frequent Keyer
- Posts: 52
- Joined: Monday 4th Sep 2006, 17:00
- Location: East View, Ky.
Cobra 138xlr squelch
I recently acquired a Cobra 138xlr and for whatever reason someone removed all the wires from the squelch control. Just wanting to know if anyone knows the precise location to re-solder 3 wires back to the pcb so I can have the squelch function back intact. I have saw the schematic, but I am not an electronics wiz. Just need to know where the wires go. I.E. c87, tr 20, bla, bla, bla.....
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ramblingman
- Technical Helper
- Posts: 331
- Joined: Sunday 21st Jan 2007, 16:35
- Location: mississippi
Probably the reason your squelch wires were removed.
Someone might have used the squelch pot for variable
power control.Bad choice by the way seeing it is a 100k pot.
Would be very touchy.The tone control pot would have been
the best bet,it is a 20k.10k is ideal for variable power for
smooth operation.Anyway its done now.Reason i tell you this
is often when people use squelch/rf gain/tone controls as
variable pots.They use the existing wires.This means they
either unsolder the wires at the pcb,Or they just cut the wires
off close to the pcb.And looking at the schematic diagram on
your radio.You need to locate vr-3 which is the squelch
threshold adjustment,there should be a wire close to it that
is clipped off close to the pcb.or like i said has been unsoldered
from the pcb board around vr-3.You will need to run a wire from this
point to the top pole of squelch control.Next locate D-16,look close
to it to find a wire that has been clipped off near the pcb,or unsoldered
in this area.You will need to run a wire from this point to the center
pole of the squelch control.Then next all is left is the bottom pole
of the squelch control,You will need to run a wire from this pole
to circuit board ground.
Someone might have used the squelch pot for variable
power control.Bad choice by the way seeing it is a 100k pot.
Would be very touchy.The tone control pot would have been
the best bet,it is a 20k.10k is ideal for variable power for
smooth operation.Anyway its done now.Reason i tell you this
is often when people use squelch/rf gain/tone controls as
variable pots.They use the existing wires.This means they
either unsolder the wires at the pcb,Or they just cut the wires
off close to the pcb.And looking at the schematic diagram on
your radio.You need to locate vr-3 which is the squelch
threshold adjustment,there should be a wire close to it that
is clipped off close to the pcb.or like i said has been unsoldered
from the pcb board around vr-3.You will need to run a wire from this
point to the top pole of squelch control.Next locate D-16,look close
to it to find a wire that has been clipped off near the pcb,or unsoldered
in this area.You will need to run a wire from this point to the center
pole of the squelch control.Then next all is left is the bottom pole
of the squelch control,You will need to run a wire from this pole
to circuit board ground.