Hi Don,
On 4/29/2012 2:54 PM, Donald Henderickx wrote:
On 4/29/2012 1:36 PM, Ed Palmer wrote:
Thank you Ed,Paul,and Marco for the reply's
The foam I was referring to is or was around ceramic base were the
igniter wire goes . Yes my wire also broke loose however I do not want
to disassemble any more than I have to. I think that just inserting it
back in to the hole and securing in some way should work. I do not
know what the potential is but I have seen a spark jump at least an
eight of an inch.
The igniter wire has to be connected to the base of the lamp. The
patent explains it quite well. Just inserting it into the hole in the
ceramic is unlikely to work. I don't know what the voltage is, but the
capacitor that stores the voltage is rated for 400V.
Does the foam look original? It definitely isn't on mine so I wasn't
sure if it was supposed to be there or not. The patent describes how
the base is the coolest part of the bulb. I don't know if a foam
covering is appropriate.
Tell me about the lamp voltage test point. My manual has no mention of
it? Were is it located?
All the test points are described on page 5-3 of the manual. The lamp
heater test point is the sixth one from the top. Ground is the seventh
point.
In you first posting I think you mentioned some grounding problems. On
this unit there is a three pin amp connector on the rear on mine the
bottom pin -20 must be grounded or the unit will not work. The red
light will come on very bright but nothing else works.I believe you
can also ground the +20 this allows this to work in various ground
polarity systems IE telco systems +ground. Perhaps I am wrong.
Do you mean the 3 pin round connector on the back? That's for an
external DC power supply. It has no other function and grounding the
bottom pin (which is ground) shouldn't make any difference.
Ed
I have Hp113,Hp115 that caution you on the ground polarity of the
systems you are installing them in. I think all the -20 floats from
chassis ground until they get to that rear plug.
Thanks for foam an fiberglass suggestions.
Hi Don,
You know that we're going to be swapping many emails, don't you? :-)
On 4/29/2012 11:16 AM, Donald Henderickx wrote:
After following Ed Palmer's thread on 304b restoration,I was
inspired to get my GTC (tracor) 304b ser#279 going. It seems that
the failure of this unit was the break down of the foam that was
wrapped around the vcxo located inside the control box. The vapors
or the moisture the foam collected corroded the steel fasteners and
caused the switches to become intermittent.
The foam around my OCXO is still in great shape. Still spongy and
providing lots of holding force for the OCXO. My unit is serial #449.
The replacement of the foam in the control box is not that much of a
problem,what I need help with is what to use around the Rb lamp
base. The foam has turned to powder.
Do you mean foam around the back end of the lamp where the wire lead
comes out or the foam that surrounds the reflector (#16 in the
picture in the patent that describes the lamp (3311775))? My #16
foam is really solid.
Should I try Home foam sealant? The cell's ,of this seem about the
same as the old foam.Will it take the heat?Should I make a
fiberglass cocoon to put around the lamp base.
Read the fine print on the can. It may list the maximum temperature
rating. I'd try a fiberglass cocoon first just because it's easily
reversible if it doesn't work. When your unit is running is the lamp
test point voltage correct?
Ed
The unit now achieves lock in about an hour. The only other thing I
did was to replace the caps in the main supply.
Any thoughts on the insulation?
Don H
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