Re: (ET) new relay in- now no reverse

[David C Robie <mycroftxx1 juno com>]

YAH - with a 15 you could go 'good hi tech'  with a new electronic
controller,  Low tech like the 16,  or no tech at all like they are
already.  First 15 I saw behind the panel made me say  'OY VAY' . Looks
like an old Jap hi fi set.  The 20 did too.  Here in this part of  New
England we got  salt air often. GE shoulda spent the necessary quarter or
so to conformal coat that PC and a buck more on the contact scheme. 
That's why my 20 is bones and the 15's just waitin for available time to
'sixteenize' her.

Dave
Weymouth MA

  

On Sat, 5 Aug 2006 18:15:39 -0400 "RJ Kanary" <rjkanary nauticom net>
writes:
>           Chances are that any SCR that you purchase today will have 
> performance specs that are light-years ahead of the "Apollo Era" 
> units that 
> were in their infancy then. Even ones from RadioShack® will fill the 
> 
> bill.Just make sure to get the terminals in the correct places.{A 
> heatsink 
> would be a plus, too. }
>          Again, an analog VOM on the low ohms scale would likely 
> provide 
> enough current to the gate to bias it ON.You can observe gate 
> closure with 
> you sand based meter. I don't have any of those cards here, since 
> any of 
> those tractors that found their way to my doorstep ended up getting 
> 'updated' to the more primitive all switches. relays, and contactors 
> type 
> control scheme. :)
>      And I think that you're beginning to see WHY.
> 
> ----- Original Message ----- 
> From: "Michael S Briggs" <msbriggs alberti unh edu>
> To: "RJ Kanary" <rjkanary nauticom net>
> Cc: <elec-trak cosmos phy tufts edu>
> Sent: Saturday, August 05, 2006 5:55 PM
> Subject: Re: (ET) new relay in- now no reverse
> 
> 
> >
> > RJ, yup, it's a DC relay. See
> > 
>
http://www.surpluscenter.com/item.asp?UID=2006080216301211&item=11-2382&c
atname=
> >  I'll check the resistance in both directions to make sure it's 
> not
> > directional though - will need to borrow an old analog ohmmeter 
> from work.
> >  Interesting point about the SCR on card 1 being what would be
> > taken out - see the post I just sent just before yours - I think 
> I've
> > narrowed it down to the SCR being the problem, just trying to make 
> sure
> > I'm looking at the right SCR (since they aren't labelled on my 
> card. Based
> > onlocation and trying to look at the etchings on the backside 
> without
> > removing the card, I think the one just under pin 8 is SCR 106, 
> the one
> > its directly connected to, but I'm not positive).
> >  If SCR 106 is dead, the plan then becomes:
> > 1. Temporarily jumper pins 8 and 9 together, with a 10A fuse 
> between them
> > (I've put a 10A fuse on wire 11 coming out of the reverse relay to 
> protect
> > it also) so I can mow the lawn tomorrow. Be very careful to wait a 
> while
> > before going between forward and reverse.
> >
> > 2. Order a replacement SCR (is this something Harrold carries, or 
> should I
> > just go through Newark?), remove all wires from card 1, remove 
> card 1,
> > replace the SCR and while the card is out, check every other 
> component on
> > there and "freshen up" the connection points.
> >
> > 3. Order a REAL reverse relay instead of a replacement part that 
> (1) isn't
> > very well built (now that I think about it, I'm pretty sure the 
> first of
> > these relays I put in was shorted across the coil connections, and
> > presumably is what fried SCR 106 or something else on card 1), (2) 
> is
> > HUGE, and thus very difficult to fit in the same spot the real 
> relay goes,
> > (3) uses screw on connections instead of spade connectors. Ugh.
> >
> > 4. Put everything back in, and hope something else doesn't fry. :)
> >
> > Mike
> >
> > -- 
> >
> > --------------------------------------------------------------
> > Michael S. Briggs
> > UNH Physics Department
> > (603) 862-2828
> > ---------------------------------------------------------------
> >
> > On Sat, 5 Aug 2006, RJ Kanary wrote:
> >
> >> Are these DC rated relays? Before you try another
> >> relay..........get your analog VOM out . Use the X1 or X10 
> resistance 
> >> scale
> >> . Measure the coil resistance in BOTH directions of an 
> uninstalled 
> >> relay.If
> >> it is different in one direction, those relays have a clamping 
> diode 
> >> across
> >> the windings to keep EMF from the collapsing magnetic field from 
> killing
> >> delicate components downstream.{Your sand based DVOM can't 
> perform this 
> >> test
> >> reliably. }
> >>      You have a 50 / 50 chance of hooking it up wrong and taking 
> out the
> >> SCR for the Reverse relay on Card 1.
> >>       Glad I could brighten your day. <VBG>
> >>
> >> Anyone else following along may wish to take note of this when 
> using
> >> "upgraded" components. Know what you are using.  :(
> >>
> >>
> >>
> >> RJ Kanary  Bandi Bros. Inc.
> >> Member TRNi  Since 1998
> >> ASE® Certified Master Auto Technician
> >>
> >> rjkanary nauticom net
> >> 
> 
> 
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