cobra 148 unlock PLL

[Low_Boy]

Funny someone marked a hfe on them?

 

[Handy Andy]

 

[ExitThirteen]

The 2166's are indeed fake. Not real. Hope you didn't pay a lot for them.


~Cheers~

 

[ExitThirteen]

These two are the real deal. The one on the right is an older one, the one on the left is a newer one, which has dots in the upper corners of the final.

Genuine Mitsubishi finals do not have the "gap" on each side of the mounting tab. They have a tabout "mark" on them, but not an actual "void" or "gap".

The other way to check for legit finals is to look on the bottom of the transistor, if you do not see a "rib" between each leg, it is a fake. ALL genuine Mitsubishi finals have a rib between the legs. You don't see 'em, they're fake.

 

[Robalo]

E 13 thank you for the info I going to be more careful i still waiting for mb8419 to finish this project.

 

[Robalo]

Finally i got it, its time to work!

 

[Robalo]

wow! almost 1000 views!
I'm disappointed, I got the same results I put in a lot of work, hours, and parts but I don't want to throw in the towel. We'll see tomorrow.

 

[Handy Andy]

Did you ever change - swap out the channel selector?

 

[Robalo]

Did you ever change - swap out the channel selector?

yes i did

 

[Handy Andy]

Ok thanks...hope these new parts get ol' Betsy to work...

 

[Robalo]

DO THIS METHOD BELOW ONLY IF YOU CANNOT MAKE THAT PLL CHIP WORK NO MATTER THAT TYPE OF TUNING OF L19 or L20 you can do - shows Pin 6 low - Out Of Lock....You have nothing left to lose...

IF you find the PLL appears dead - ground Pin 10 - try again.

Rotate you channel selector - try various channels and tweak L19 and L20 as a means to see if you can lock it in - it may not be a channel or a frequency on the standard 40.

Still dead?

Pull up Pin 10 with a 22K resistor jumped to Pin 9 (8VDC) - try again.

did not work this test

 

[Handy Andy]

Wow - channel selector changed too - this isn't making any sense...

You get 8V

PLL swapped out - lots of times.

UHIC no dice yet...

MB3756 seems to key up

Just trying to fix PLL Lock on Pin 6...

So if the channel can be changed does the Pin 5 of UHIC chip show any variation?

Else only other part that can even try to go bad is L19 - but that is a long shot...might have to take that one apart to see if it has an open wind.

Just need you to check the L19 if it's pads show a short but not to it's case...

 

[Robalo]

Ok here we go again on c1 or pll circuit I removed c87,r95,r97,c79,c91 and r207
now ic1 pin 5 charge pump has 8.24v and pin6 loop detect 0.0v . the rest of pin are ok. I try with 9 micro chip same results. pin 5 should be 3.45v and pin 6 8.0v whats going on

 

[Handy Andy]

PLL ROM - did you try all channels?

 

[Robalo]

PLL ROM - did you try all channels?

yes i did it