For the mating connector go to WAL*MART. In the auto section they have
"conversion" plugs for GM cars/radios. Some of them have a wiring diagram
included. If that doesnt do the trick look in a manual (at Autozone or pep
boys) for a wiring diagram. The radios used in GM cars are pretty standard
and interchangable...good luck.

wrote in message ...
I'm looking for suggestions (preferably other than "Trace the internal
wiring, Idiot!" or "Next time, buy a radio with a manual, Idiot!) on how
to determine the pin-outs of a Delco AM/FM radio "about 10 years old"
that came with NO manual and has NO identification other than MTD-1316
stamped into the metal on the rear.

On the rear, in addition to the standard antenna jack, there is one 13-pin
recessed (mostly?) male connector (I do NOT have the matching connector)
for which (I'm hoping) someone will recognize the pin-outs. If =
represents a horizontal flat "pin", o represents a slight dimple (but
NOT a hole) in the plastic which holds the = pins, 0 represents an
actual hole which goes through the plastic, and everything else represents
the shell and keying plastic, the plug kinda looks like this:
___________________
/ = = = | 0 | = = = \
| o o o o o o o |
| = = = | = | = = = |
+-------------------+

I'm NOT going to try to "draw" an actual ASCII picture of the front of
the radio, but it has the following controls sorta in the indicated
positions:
+----------------------------+
+---+ TREB SET | |
|PWR| | |
+---+ BASS AM-FM | |
| |
BAL +----------------------------+
UpArow UpArow ==== ==== ==== ==== ====
VOL FADE TUNE
DnArow DnArow SEEK RCL SCAN
========= ======= =========

CONCLUSIONS SO FAR:
* It is obviously digitally-tuned and probably has only five digital
memories for each band.
* The BALance control implies the radio has at least two speakers.
* The FADE control implies the radio has four speakers.
* Because the PoWeR switch BARELY depresses and does NOT have two
distinct positions (instead, it has a plastic-covered hole probably
for a pilot-light to show through), the switch probably controls
some electronic circuit to turn the radio on and off.

GUESSING:
* Each group of three = = = pins probably belongs to one speaker,
and an internal examination may show the middle pin is ground.
* The HOLE in the top row EITHER
* doesn't have a connector hidden behind the plastic (in which
case the chassis will be GROUND) OR
* if there is a hidden connector, it will be GROUND (like a U-GROUND
outlet) (My reasoning: one would NOT want the matching connector
to have a hot 12-volt pin sticking out like a sore thumb!)
* The pin immediately below the hole will then be for +12 volts.
* Since all 13 pins are now "accounted" for, there probably is no
antenna-control power wire.

I am definitely open to other possibilities!

--Myron, W0PBV.
--
Five boxes preserve our freedoms: soap, ballot, witness, jury, and
cartridge
PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785)
539-4448
NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle,
Pistol)