BCD436HP Discriminator and Teardown

Status
Not open for further replies.

N9JIG

Sheriff
Moderator
Joined
Dec 14, 2001
Messages
4,061
Location
Far NW Valley
I had so much fun tearing apart my 536 this afternoon I did the same with my 436 tonight.

The 436 will be tougher to mount a discriminator jack like any handheld. If I were to actually run the jack I would use a pigtail like I did with my Pro83 a few years back. There just is no easy place or way to do so otherwise.

Before you dig in remember that it is your radio and your fault if you hose it up. I am not responsible for errors or if you smoke your new toy.

Tear down:

Remove the batteries and antenna.

Remove the 4 screws on the case back and the 2 inside the battery compartment.

Gently pull the front panel off.

Remove the threaded antenna retainer. I uses a small jeweler’s screwdriver.

Gently pry up the control knob and remove it.

Remove the 4 screws marked with arrows on the board after setting aside the radio’s front panel.

Press in gently on the battery spring terminals to release the main board from the case. Be careful, as this also releases the control daughter board and a metal shield.

To the right of the large metal shield, just left of the two side mounted microswitches is the Discriminator tap point. Uniden nicely labeled it for us, it is the solder pad above the label:




Don't forget the ground on your pigtail.

Reassembly:


Replace the shield on the main board, there are 2 capacitors that have matching holes.

Insert the daughter board into main board, watching that the panel connecter is properly inserted.

Insert the 3 piece board assembly into the rear part of the case, with the antenna and control knob inserted first. Gently press down on the bottom part of the assembly watching the battery terminals carefully as they go into the case. While doing so jiggle the rubber boot for the left side switches (the one that says Menu and Func on it.

Replace the 4 screws holding the board to the rear case.

Replace the rubber boot for the right side switches

Replace the front panel, watch the rubber boots.

Place the radio face down on the desk and replace the 6 rear screws.

Replace the control knob as well as the retaining nut for the antenna jack. Carefully tighten it down. Replace the antenna, batteries and battery door.

If it all works again, your welcome.
If it doesn’t, you are on your own…

As for how to get a connection to the outside world for the discriminator you might be best to use a pigtail, due to the tight clearances in the radio. If you are real ambitious you can try modifying the earphone jack or mount a jack on the radio someplace.

Here is the radio in pieces after disassembly:





Here is the main board:



Here is the display and keyboard boards:



The Daughterboard:






*** Looks like there might be a second discriminator point here...

Explore at your own risk!
 
Last edited:

Dewey

Member
Joined
Dec 19, 2002
Messages
977
You are one brave soldier!!!

EDIT: Looking at the main board, it looks like Uniden has improved the GPS connection. I remember with either the 396T or the 396XT, some were complaining of the GPS jack separating from the board. Thanks again.
 
Last edited:

NUGEN

Member
Premium Subscriber
Joined
Jan 16, 2013
Messages
130
Location
Phila, PA
I wonder when Uniden will start providing replacement parts. I see they changed the speaker assembly from the 396. It looks like the metal spring type connectors touch the other board to provide the audio. I also wonder when they do provide replacement speakers will they have that spring piece presoldered onto them already.
 

W2SJW

Senior Member
Moderator
Joined
Nov 22, 2001
Messages
3,163
Location
Northwest NJ
Rich,

Thanks a million for doing this! Just in case anyone is wondering - if you get dust behind the plastic screen cover (not sure how the hell that happened on mine, but it was enough to drive me nuts!), taking out the 6 screws & lifting off the front cover is as far as you have to go.

Just a little canned air & a microfiber cloth & you'll be golden... ;)
 

kwd57

Member
Joined
Feb 8, 2007
Messages
57
Did you see the mystery backup battery that was said to take 50 hours to charge?
 

yaesumofo

Member
Joined
Jan 4, 2003
Messages
314
Location
los Angeles
Very cool. The radio looks very sophisticated.
There is a spot in the last image at the top edge of the can where it says epoxy but there is none. those diodes may look tempting to some....
The build on these radios is very clean. They are clearly using high quality automated assembly techniques.
Nice.
yaesumofo
 
Status
Not open for further replies.
Top