[Hallicrafters] My First Boat Anchor Restoration: SX101 MkIII

[Jason Hissong]

Quick question, will a 12BY7A work if I got one off of ebay?

Jason

On Mon, Nov 14, 2011 at 2:37 PM, Jason Hissong <jhissong at gmail.com> wrote:
> I was reading something about the 12BY7 going bad after a while.
> Maybe I will put a power strip in and turn it off at the source to
> save the tube.  I am wondering if that tube is the problem itself.
>
> I will check tonight and see if the tube is even working.
>
> Thanks again guys!
>
> Jason N8XE
>
> On Mon, Nov 14, 2011 at 2:11 PM, Mike Everette <radiocompass at yahoo.com> wrote:
>> Jason,
>>
>> Something else you might check... take a look at the tubes and make sure the correct tubes are in the sockets!
>>
>> I experienced this with an sx-100 a number of years ago... brought it up pn a variac, and no signals except a few in the 12-34 mc band.  Noise on the others except for the AM BCB which was stone dead.
>>
>> Guess what... the first mixer tube had been replaced, probably by the seller to fill an empty socket before taking it to the hamfest.  The tube was a 6AG5, instead of (I think) a 6BA6.  Don't ask me how the thing was working on band 4 (12-34 mc) because the basing of these tubes is totally different except for the filament pins.  I put the right tube in, and WHOOOOOOOMMMMM -- here came the signals!
>>
>> You should clean all the tube and socket pins, preferably with De-Oxit.
>>
>> The "always on" oscillator filament feature means you'll be replacing tubes every few months.  Otherwise, you'll surely like the 101 Mark III.  I think it is the best of the 101 series.
>>
>> If they just weren't so heavy...!
>>
>> 73
>>
>> Mike
>> W4DSE
>>
>>
>>
>>
>> --- On Mon, 11/14/11, Ross Stenberg <k9cox at charter.net> wrote:
>>
>>> From: Ross Stenberg <k9cox at charter.net>
>>> Subject: Re: [Hallicrafters] My First Boat Anchor Restoration: SX101 MkIII
>>> To: hallicrafters at mailman.qth.net
>>> Date: Monday, November 14, 2011, 1:17 PM
>>> Could be the LO is not on due to a
>>> resistive heating device (I forget
>>> what they are called) being open. I had it happen to me
>>> once and
>>> replaced it with a resistor and it came back to life.
>>>
>>> On 11/14/2011 10:20 AM, Jason Hissong wrote:
>>> > Hi guys,
>>> >
>>> > I am new to using and hopefully restoring old
>>> radios.  I have grown
>>> > particularly fond of Hallicrafters gear since I got my
>>> HT37 at Dayton
>>> > a few years back.  Well, I picked up an SX101 Mk
>>> III at Dayton this
>>> > past year.
>>> >
>>> > When I opened it up, it appears that someone already
>>> went in and
>>> > replaced the caps with Olsen type "TV"
>>> Capacitors.  It also appears a
>>> > few caps were added to the capacitor can in the power
>>> supply.  I was
>>> > told by local hams to replace the Olsen caps so I plan
>>> to do this.
>>> >
>>> > The unit is in great cosmetic condition.  When I
>>> fire it up, there is
>>> > no hum whatsoever.  All the features appear to
>>> work, selectivity,
>>> > volume, notch, mode switch, audio etc.  However,
>>> I hear barely
>>> > anything coming out of the receiver with the RF gain
>>> all the way up.
>>> > I went in a cleaned up the band switch contacts and
>>> that improved
>>> > things somewhat.  I can hear signals, however,
>>> the frequency does not
>>> > change when I turn the VFO knob. The volume changes
>>> (i.e, the receiver
>>> > appears to get less sensitive as I move away from a
>>> particular
>>> > frequency).  This only happens when the
>>> Calibrator is engaged (which I
>>> > picked up after I got the radio).  With the
>>> calibrator off, I hear
>>> > nothing.
>>> >
>>> > I went ahead and ordered a cap replacement kit for it
>>> from Hayseed.  I
>>> > am hoping there are some bad caps in there.
>>> >
>>> > Any tips or a general idea what may be going wrong
>>> would be
>>> > appreciated.  This will be my first boat anchor
>>> project.  I do have
>>> > experience building kits (I have build a few K2s, KX1,
>>> etc)
>>> >
>>> > Thanks es 73,
>>> > Jason N8XE
>>> >
>>>
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>