[Motorola] Need FID for Mitrek T81JJA

[Paul Cavnar]

> While you have da-book out :)
> What are the levels of the; SW B+, B-, and the routing
> for the SQUELCH and VOLUME lines ? 

SW B+ is Vehicle battery-positive
SW B- (Pin 6 jumpers to 17 for Gnd

SQUELCH ties directly to the wiper on the squelch pot.
VOLUME ties directly to the wiper on the volume pot.

> Chan Select is prob
> same as Micor - (7/8/9/10) to GND to select, and PTT is
> Hi-to-Lo to key ?

Correct on the Chan Select.
PTT LO goes to ground to xmit and 
PTT HI goes to ground through a pilot light XMIT indicator

> Is circuit "B" looking for an internal regulated voltage,
> or same potential as "A" (eg A+ to B+, A- to B-) ?
> A+ and B+ in the Micor are the same levels, iirc.

A+ goes through the main fuse to the battery
SW B+ (4) connects to A+ (13) for "power on"
A- and B- are comon

> All I really need to do for now, until I get a cable
> and remote head is verify operation with test leads.
> (guess I'd better find a head and cable for this ;)

I have a 4-ch Mitrek head I'll include with the other
stuff we discussed.... :)

> I have a spare TLN1096A-3 (from a Micor) with the pots
> in it, if I have to provide a balanced resistance to
> the SQUELCH and VOLUME lines.

The old metal MICOR, MOTRAC, T-POWER heads will
work fine - you just have to watch the wiring.  Don't forget
NOT to ground the Mitrek audio output - either side since it
is isolated from ground on both leads and does not use an
output transformer.  Grounding one side of the speaker can
destroy the audio output section....

> I'm assuming (hate doing that), that the DET AUDIO, and
> Discriminator Buffer Out on the Micor, are one in the same,
> and used to feed the SQ and VOL controls.

Draw a small schematic with a single common point in the
center.  This is pin 11, DET AUDIO.  To the right, is a 3.3k
resistor connected to the high side of the SQUELCH pot.
From the single common point, connect a 10k resistor that 
goes to the high side of the volume control.  The outside of
both pots go to ground. 

Paul