[time-nuts] General Technology Corp model 304b

[Donald Henderickx]

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.
Tell me about the lamp voltage test point. My manual has no mention of 
it? Were is it located?
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. 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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