The Defpom Forum, for RadioMods, S&M Software and Music by The Defpom

Radio Make and Model: 1978 -1997 COBRA 148 GTL
PCB Number: PC 412
PLL Number: MB8719
Test gear available: VM METER HP O SCOPE SIG GEN
Symptoms: BLOWN D44

What is working: THE RADIO IS WORKING

What has been tried: REPLACE THE DIODE

Did it suddenly happen ?: After overvolt or shorted transistor.
Anything else that may be of help?: It is a common problem i see all the time when restoring these radio`s. it is supposed to be a bad transistor that makes the diode blow. if you put a new diode in it blows the fuse. the radio works fine with d44 out of it. can you help out rick or anyone. thanks very much in advance.

d44 is the anti spiking diode
i would check the big electroylic cap,in the right rear corner of pc board
it will be a 470 mfd @ 10 vdc,i think it is c-135 or 136
anyway if it needs replacing replace with a 470 mfd @ 25-35 vdc

nope try again. thanks for the info but there are no caps with any values that are even close to that. i did replace a large cap by the transformer. it was shorted but it still did not fix the d44 issue. those numbers you gave are 2 small caps by the voltage regulator. thanks alot. anyone else?

are all the voltages correct at the voltage regulator??

Ok i figured out what it was it is a ceramic cap a green one on the right side of the radio right by the audio chip. it was a dead short in the cap that caused the d44 to blow. c 235 is the cuprit. i put a new d44 in and changed the c 235 and it fired right up. no more blown fuse. this is a breakthrough for me. i am very happy that i figured it out.