SMT Bodges on back

[LeapFrog]

I understand these are here because at some point in manufacturing or development a change had to be made and it was too late in the game to revise the PC board.
(Just my personal conclusion)

Anyway my question will stay in regards to the Cobra 29 LTD Classic Radios..
[photo="medium"]4100[/photo]

• How can I find the amount of these that are supposed to be on the board from the factory?
  Cobra 29 LTD Classic (kepc-060G board )

• Where can I find these components (that are to be on the solder side) on the schematic, one is D13 I gather from internet searches..
  
  • Lastly, are all of these varactor/varicap diodes?

All the best.
-Sam (aka Leap)

 

[Tallman]

Those could be Engineering changes or some one has been in your radio.

 

[Tallman]

I have opened brand new Ranger Radios and found the very same things on it. Some times the person who does the PCB layout will miss a part every now and then and that's how they fix it. Cheaper than tossing out an entire PCB purchase just for one mistake.

 

[Tallman]

Could items could be the SCHOTTKY diode modification for receive boost?

Check here!
http://www.cbtricks.com/radios/cobra/29ltd_29ltd_st_29wx_st/index.htm

 

[LeapFrog]

Not in this area for the VCO! The schottky diode mod is well known, these parts do not go along with it.
In that mod people remove original diodes and the first transistor and replace the original components (not add on more).
This is not an after-market modification I am fairly certain these are factory updates to the circuit.
Searching the term "KCD-1SV215" will lead one to the forum thread I am talking about.
Although the schematic labels it correctly as a SVC251 at D13

 

[Tallman]

http://www.cbtricks.com/radios/cobra/29ltd_29ltd_st_29wx_st/index.htm

Here is some reading for you!

 

[Tallman]

If I could look at it hands on I would find out where those item connected to by looking through the circuit board with a strong light shining on the circuit board and determine what parts they are connected to then the schematic to determine the function.
For instance connected to R50 and TR66 ..... Fictional designators

 

[Captain Kilowatt]

If I could look at it hands on I would find out where those item connected to by looking through the circuit board with a strong light shining on the circuit board and determine what parts they are connected to then the schematic to determine the function.
For instance connected to R50 and TR66 ..... Fictional designators

I used to use a cheap laser pointer for that. The high intensity little red dot showed up really well on the other side of the board.

 

[LeapFrog]

Captain Kilowatt that was an amazing suggestion (Simple, but not thought of at first).

I will post the two smd parts location and designation when I get a chance..

 

[Captain Kilowatt]

Amazon has laser pointer pens for less than $10. Ihave even seen them in dollar stores for $2.00. The batteries with them cost more than that.

 

[Tallman]

I use the red laser pointer that I bought at a Walgreen's for $3.00.
I knew not every body had lasers so the strong light works out too. I have used the laser off of my Glock Model 22. The one from the Glock was stronger than the Walgreen's unit.

 

[LeapFrog]

When I get a good chance to sit down and Fiddle with the radio I will update this thread tomorrow.
-Sam

D13 1SV215 Varicap Diode
D16 1SV214 Varactor Diode
Will be found on the bottom of the radio..

A few capacitors belong on the bottom as well, If anyone can give a definitive answer as what is to be found on the solder side of a 29 LTD Classic I would be indebted to you.


If i'm too darn stupid to understand something already posted here please let me know!
How does the tech understand what belongs on the bottom or top, does he really examine the board in great detail and look for components that should be there according to the schematic and compare whats in his face?....
Thanks i'm just another ignorant radio newbie
-Sam