[time-nuts] General Technology Corp model 304b
paulswedb at gmail.com
Sun Apr 29 23:18:13 UTC 2012
Curious is the manual online?
Would be interesting to look at.
On Sun, Apr 29, 2012 at 6:33 PM, Ed Palmer <ed_palmer at sasktel.net> 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
> 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
> 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.
> 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
>>> 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?
>>> 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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