Re: (ET) Fwd: Re: Card 1 wire 8 or...

Pin 7 of Card 1 is the sense pin for the armature voltage and is part of the circuit that is supposed to lock out the field reversing relay until the back EMF has dropped to a “safe” level that won’t burn the relay contacts. See page 5-3 of the HSM for further reading.

By wiring this pin to wire 8, which would put it directly in parallel with the high side of the armature would probably be the more conservative (reliable) place to wire it if you want to read armature voltage. Putting it on wire 6 would add the two armature resistors (R1 and R2) between the sense and the armature. Having it on wire 6 would actually put it electrically “closer” to the field winding.

I’m not sure which would be the better choice. The manual’s description of the circuit function refers extensively to the armature back EMF and not field potential (maybe the voltage spikes of the field are prone to taking out the card components?). Either should work, and accordingly I would probably leave it as it is. However, there would be no harm in rewiring to wire 8. Perhaps this change in the manual was done to help mitigate card and relay failures, who knows.

This is not the only error in the manual. The E20 diagrams have a few non-conformities also.

Nick

From: stupidemail5 lycos com [mailto:stupidemail5 lycos com]
Sent: Thursday, April 30, 2015 8:17 AM
To: Elec-trak cosmos phy tufts edu
Subject: Re: (ET) Fwd: Re: Card 1 wire 8 or...

So it looks like the troubleshooting manual disagrees with itself

page 21 of my manual, dated 11-72, the schematic shows wire 8 on pin 7 of card 1, while the control panel layout shows wire 6 on pin 7.

I guess the question is, is there a problem, and should I fix it? With my limited knowledge it 'seems' like wire 8 is a better idea.

Just checked my E12S it also has wire 6 on pin 7

On 2015-04-29 22:26, stupidemail5 lycos com wrote:

26AE15CB
MN22379

I have the hsm on pdf and paper, the troubleshooting guide pdf and paper and the full green looseleaf binder of the dealer manual

most places call for pin 7 to be wire 8 except for the one place in the troubleshooting guide that lists it as wire 6 but it is only a partial

On 2015-04-29 22:07, RJ Kanary wrote:
Physical locations of the numbered wires on the numbered pads are available on Page 5-26 on Paper, Page 132 in .PDF.

RJ
On 4/29/2015 2:46 PM, stupidemail5 lycos com wrote:
Umm, I have all of the manuals, although I am not looking at all of them now, but that is why I know the wiring diagram says it should be wire 8 and it is in fact wire 6. This is an original AFAIK unmodified machine. The original connectors used on the card edge fell off the card from just opening the panel, and are brittle so I have replaced them with a 'real' edge card connector, and in the process of doing so kept track of the wire numbers thus discovering the anomaly

Is there an earlier/later wiring diagram that shows this as normal?

On 2015-04-29 17:43, RJ Kanary wrote:
Do you possess a Homeowners Service Manual? If not, I can PM you some helpful illustrations.

RJ

On 4/29/2015 12:54 PM, stupidemail5 lycos com wrote:
http://www.elec-trak.com/forum/showthread.php?5605-My-recent-Ebay-find-barely-used

this is the machine

On 2015-04-29 15:54, RJ Kanary wrote:
The information on the plate riveted to the front battery compartment would be most helpful...... :)

RJ
On 4/29/2015 11:44 AM, stupidemail5 lycos com wrote:
Mine seems to have wire 6 where wire 8 wants to be [pin 7] and it rings out to be wire 6 and is labelled as such

This is on the machine I just bought and I have not run it, and it has not run in a very long time

ideas?
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