Connex cx-36hpf bias

[Eldorado828]

One of the other drivers was having an intermittent issue with his connex and had me take a peek inside just to check the obvious. Turned out to be tr-41 having some cracked solder joints on the board. The radio now works like it should but looking around inside I found some things different and new to me.

Maybe it's been a while since I've been in a 3600 board, but the final section isn't what I recall in others like the 33hp or 3300 seen before.

Vr20 and the parts to go with it aren't there..... Vr10 is still there though and L33 is different too?

So how would you check bias voltages? So would you go vr11 for the driver and vr10 for both finals on this one?
Just trying to understand why they did that.

 

[Crossbow]

VR11 sets the driver voltage and VR10 sets the voltage for both the finals.

 

[Eldorado828]

VR11 sets the driver voltage and VR10 sets the voltage for both the finals.

Thank you for the reply, so it seems they have changed it since the last time I dug into a 3600 board.
I see they did away with the diodes under all the finals too...

I guess they're nickel and dime'n components out to save money but selling them for more.

Thank you for the response

 

[Crossbow]

Yep they changed a few things around on this unit. If you noticed they ran another jumper back there from one gate to the other gate allowing one trimmer to control the voltage on both finals. These seem to be some good working radios.

Take notes and pictures of that back panel. I have copied how they done this radio and changed out a few of the old single bipolar radios using this new way on putting triple mosfets in them. Worked out perfect!!

 

[Eldorado828]

10-4, I'll keep that in mind and take some pictures for future reference. I was going to do the talk back modification on it since he asked but I'll do it another time as I've got some notes somewhere unfound at the moment. It's repaired now and working well so I won't touch anything else inside now. Just had me curious about the way they bias these now. Learned something new.

 

[Crossbow]

Here ya go.

 

[Eldorado828]

Thanks again. I've got that one for the 14b board but there's a slightly different one for the 15c that works a little better. I won't take credit for it as it was shown to me by Don in Erie Pennsylvania. I had shared it on cbt when it was alive but also had it written with photo somewhere in my notes. Just gotta find it, and when it's found I'll be sure to post it here.