[Hallicrafters] SX-117 disaster

Tue Aug 2 19:30:39 EDT 2016

Thanks all for your help.  I've gone through everything, and it looks 
like the 50.75 kc system is shot.  One coil totally destroyed.

Can anyone advise if any of the 50.75 KC transformers from the other 
Hallicrafters rigs will work, if I'm lucky enough to find some?  Based 
on the sounds of things, I think the 1650 KC ones are shorted out 
internally as well.

These are similar to the SX-101s...

I appreciate everyone's help and messages.  Totally disheartened.

Jeff

WB3JIH

On 8/2/2016 2:41 AM, Richard Knoppow wrote:
>    Check R-64 and R-63 for value.  This is a voltage divider from the 
> B+ that sets the voltage at pin-2. I don't know how this relates to 
> the RF being burned but worth checking.  Its possible the AVC is 
> partly shorted due to a fried cap in the RF but this is pretty removed 
> from there.
>
> On 8/1/2016 7:58 PM, Jeff wrote:
>> Doing some voltage checks this evening, and interesting observations.
>>
>> I'm leading towards the AVC, as I'm not getting much fluctuation on the
>> S-meter (meter movement seems OK...).   DC Voltage checks on all of the
>> tubes show very close to the manual specs, with the exception of V10B,
>> Pin 2.  My manual indicates that the voltage there should be 24 volts,
>> and I am seeing 4.
>>
>> Any thoughts?
>>
>>
>>
>> On 7/31/2016 11:47 PM, Richard Knoppow wrote:
>>>    Well, the cap is easy enough to check, a VOM will tell you if its
>>> shorted and depending on the value may give you a kick if its OK.  My
>>> guess is that its OK.
>>>
>>> On 7/31/2016 7:44 PM, K9FFK wrote:
>>>> Jeff:
>>>>
>>>> C4 is also a suspect. Its a 300V mica.
>>>>
>>>> If it is shorted, AVC goes to ground through L5 along with V1's
>>>> bias...red plates.
>>>>
>>>> If it is open, no signal. V1 is normal. Receiver is deaf.
>>>>
>>>> Dick, K9FFK
>>>>
>>>>
>>>> On 7/31/2016 7:26 PM, Jeff wrote:
>>>>> Thanks to all the fast responses. I've drowned my grief a bit, and I
>>>>> did some disassembly.  The Antenna coil surely does look like it got
>>>>> toasted.  I've included an image on my webserver:
>>>>>
>>>>>
>>>>> http://www.podengo.com/sx117/L5.jpg
>>>>>
>>>>>
>>>>> In looking at it, it looks as if the coil form actually deformed
>>>>> (inside) so that the slug won't move past a certain point.  I don't
>>>>> see any damage to rotary switches or other components. The 6DC6s test
>>>>> OK, but I don't have any replacements in my stock to try a different
>>>>> one.
>>>>>
>>>>> Anyone have any advice on the coil (or a spare you can part with?)
>>>>>
>>>>>
>>>>> Jeff
>>>>>
>>>>>
>>>>>
>>>>> On 7/31/2016 3:05 PM, Jeff wrote:
>>>>>> Looking for some advice or consolation...
>>>>>>
>>>>>> Previously well working SX-117/HT-44 twins.  I hadn't run them in a
>>>>>> long time, and many cables got messed with in the mean time.
>>>>>> Unfortunately, in my haste to hook the pair back up again, I got the
>>>>>> transmitter output fed into the receiver antenna input... and then
>>>>>> hit transmit to tune up the transmitter...
>>>>>>
>>>>>> It's taken me a while to stop cursing about it, but now my SX-117 is
>>>>>> deaf as a post.  A quick check of the RF amp and 1st mixer show that
>>>>>> the tubes are OK.  A signal generator on 14.250 is barely audible,
>>>>>> but I can no longer get a good strong peak on the preselector.  I 
>>>>>> can
>>>>>> get a bit more of a peak on 40 meters, but it's still quite deaf.  I
>>>>>> had the rigs in 20 meters when the mishap occurred.
>>>>>>
>>>>>> It's just about acting like there's no antenna at all hooked to it.
>>>>>> I get no increase in noise whether or not it's hooked to the antenna
>>>>>> or dummy load.
>>>>>>
>>>>>>
>>>>>> I've had the courage to admit I've done something heroically stupid
>>>>>> -- so I'm reaching out to the list for any thoughts or guidance 
>>>>>> as to
>>>>>> how to fix this.
>>>>>>
>>>>>>
>>>>>> Jeff
>>>>>>
>>>>>>
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>>>>
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>>>
>>
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>