Cobra 148 GTL Not powering up.

[American-Vulture]

I have a cobra 148 gtl not powering up.nothing.
Have voltage at on/off switch so looks like diode is ok.This is a frankinsteind radio.
I cant believe what I bought.It has 4 slide switches underneath radio.Looks like an eq board.
The speaker is gone and in its place is this big ugly board that looks like it came out of an old tape recorder
or something.
Any ideas,The board is not connected .

 

[OldTech03]

We need images GOOD IMAGES so we can see what you are seeing. Do you have any lights?

 

[sp5it]

Take a DMM and find where voltage disappear.

 

[loosecannon]

do you get 13.8 volts at pin 2 of the MB3756 voltage regulator?

yes?
check voltages on the other pins of the voltage regulator.

no?
unsolder the voltage regulator's pin 2 from its trace, and make sure there is no connection between it and the trace.

now measure the trace and see if there is 13.8 volts there.

also, i would put a 1 amp fuse in line just as a safety precaution.
LC

 

[American-Vulture]

We need images GOOD IMAGES so we can see what you are seeing. Do you have any lights?

No lights .

 

[American-Vulture]

do you get 13.8 volts at pin 2 of the MB3756 voltage regulator?

yes?
check voltages on the other pins of the voltage regulator.

no?
unsolder the voltage regulator's pin 2 from its trace, and make sure there is no connection between it and the trace.

now measure the trace and see if there is 13.8 volts there.

also, i would put a 1 amp fuse in line just as a safety precaution.
LC

I think I got 13.8 at one and three.dont sound right.

 

[Low_Boy]

That is a Radio Shack cant remember the number off hand echo board. It came from Radio Shack in a counsel people used to put them in radios before the modern echo boards came out. I have a radio here that had one in it.

 

[American-Vulture]

I don't know it is very large the throw in the switches is better than an inch.
two wires coming from it and I haven't found out what part of the radio they connect to.
Also there is a jack in it to plug a power supply into but it is enclosed in the radio.
I will try to post some pics.

 

[nomadradio]

Remember that the mike must be plugged in to hear the receiver audio in this radio.

There is a single point LED on the front of the radio. Should light up green while receiving, and turn red when the mike is keyed.

Do you have an antenna attached to it?

73

 

[American-Vulture]

Remember that the mike must be plugged in to hear the receiver audio in this radio.

There is a single point LED on the front of the radio. Should light up green while receiving, and turn red when the mike is keyed.

Do you have an antenna attached to it?

73

Have a meter attached.Not getting any power to the volt reg ic.
It has weird mods done to it.The board only has two wires to attach to the radio .
Trying to make it normal so it can be trouble shooted.Otherwise out in the trash it goes!

 

[American-Vulture]

We need images GOOD IMAGES so we can see what you are seeing. Do you have any lights?

No lights, no smoke, and no sparks either.

 

[kopcicle]

and no pics...

 

[nomadradio]

If that much stuff has been modified/changed/trashed, you may need a working radio just to serve as a model to copy from.

Bad news is your model would have to come from the same production era.

Not so different from a passenger car model that was sold for ten or fifteen years. The wiring diagram, wire colors and such will change from year to year.

The 148 was made in a half-dozen or more different factories and even more versions since 1979.

Sounds like it may have been "shade-treed" beyond just a repair job. Sounds more like a restoration task.

73

 

[American-Vulture]

and no pics...

Do not know how to add pics.IM working in a fog here!

 

[kopcicle]

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