This pictures shows the internal HEI shematic and wire circuit but not
the IC circuit. The RH you referred to on the left side could require
a correct polarity. If inputing external power source as to trigger,
it normally requires a correct polarity.
Great info on that page, but one last point of confusion: We see the
upper-left terminal marked + connected to the coil primary +, and the
lower-left terminal connected to the coil primary -. This must mean the
module is fed +12V in parallel with the primary + of the coil, yes? That
is, an ignition switched source of +12V must simultaneously feed the
upper-left module terminal and the coil primary +, yes?
I'm not certain what is meant by the right hand on the left side, but
yes--on some HEIs, the pickup coil leads are crossed while others are
not; it is advisable to retain this configuration when switching
modules. Crossed or not was indicated by color of the connector;
crossed pairs usually have a white or black connector, non-crossed
yellow. Some sources indicate that a crossed wire pickup requires the
primary winding leads to cross as well. Failure to retain proper
orientation here can lead to intermittent "no start" or "no power"
problems. However, the pickup coil (timer core in GM speak) produces an
analog (AC) signal, so polarity isn't necessarily an issue, particularly
since the original poster suggested that he was using the HEI module to
rig a non-GM car. The zero voltage threshold (switchover from
"positive" to "negative" portion of wave as viewed on an oscilloscope)
of the pickup's signal is interpreted by the module (effectively a
Darlington pair) as in instruction to open the primary winding circuit
(as connected to module terminal C.) All electronic ignition modules
require a power source, thus the B terminal should receive 12v from an
ignition-switched source. The remaining terminal is the aforementioned
trigger, terminal C. This connects to the coil negative side, as
virtually all ignitions are ground-side controlled, and leads into what
amounts to a relay inside the module, which is used to interrupt primary
current. We are *not* inputing an external power source here, that
would lead to bad juju, like car no vroom vroom. The ignition fires the
plug by interrupting primary current flow, thus collapsing the magnetic
field inside the coil assembly and inducing voltage in the secondary.
Grounding of an HEI module is provided through the case of the
component, where one of the mounting screws shoulders against a metal
ring embedded in the plastic.
Correction, the RH (right hand) he referred to on the right side.
(This is grammatically redundant, please ignore.)
Correct, the reluctor produces an AC sawhorse waveform. I`d noted just
in case some reluctors have embedded polarized capacitors, which is
unlikely. Or an external trigger is used in case of non-GM
applications or modified for computerized control, which is unlikely.
Note that the post read "...*what amounts* to a relay inside the
module.." (emphasis added). I concede that an actual relay is not
contained in the module, but as the circuit in question is switched by
an output associated with the module's dwell predictor circuit, the
function can be likened to that of a relay, which is all I intended to
express. I stand by my words.
CORRECTION; the RH is on the `RIGHT` side.
This picture shows the internal HEI schematic and wire circuits but
not the IC circuits. The RH you referred to on the ``RIGHT`` side
could require a correct polarity. If inputting external power source
as to trigger, it normally requires a correct polarity.
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