Hi Don,
On 4/29/2012 6:41 PM, Donald Henderickx wrote:
On 4/29/2012 6:27 PM, Ed Palmer wrote:
Yes, there's a partial copy of the manual online. It's missing a few
schematics, but is otherwise complete.
http://sundry.i2phd.com/ServiceManual_304b.pdf
Ed
The bottom pin is not chassis ground,on this unit.
The bottom pin (pin B) is connected to circuit ground which is connected
to chassis ground on my unit and the schematic confirms it. That could
be why you have to ground that pin to make your unit work. There
appears to be a broken or missing ground somewhere in your unit.
The foam looked original before in crumbled.
That's good to know. Thanks!
The 400v cap in the ignitor circuit dumps into the primary of a
autotransformer, from the spark I observed I would i would guess 10kv>
so I do not think intimate contact is necessary
I looked right at the autotransformer on the schematic and still didn't
see it.
You asked about lamp voltage test point not lamp heater test
point,that is what confused me. I will check it when I power it back up.
You're right. Sorry for the confusion. This has not been one of my
better days.
Ed
On 4/29/2012 5:18 PM, paul swed wrote:
Curious is the manual online?
Would be interesting to look at.
On Sun, Apr 29, 2012 at 6:33 PM, Ed Palmer<[email protected]>
wrote:
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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