[Hallicrafters] Very slow warm-up for SX-62

[Carl]

Bill,

Then Id suggest taking it out of the case and flipping it over and get an 
idea of whats going to be involved.

Its always best to replace the PS and audio electrolytics as well as all 
paper caps in the audio stages. Then there is a minimal chance of causing 
transformer damage.

Replace a few caps at a time, turn on and check that you didnt goof and keep 
going. Its also easy to check resistors along the way. Since there is no 
such thing as a completely accurate schematic dont worry about it unless a 
major problem creeps up. Just do the caps and resistors around 3 at a time 
and creep along.

Most of the set is just crowded but its not all that hard if you have a 
small iron. Its the stuff under the bandswitch that will require learning 
some new cuss words.

Between the SX-42 and 62 series Ive gone thru about 25 of them and made up 
some tools to speed the process but it is still an involved set.

Depending upon production date you may also have intermittent IF capacitors, 
aka SMD: Silver Mica Disease.

Have fun! Its a great radio when finished.

Carl
KM1H




----- Original Message ----- 
From: "Bill Husted" <bhusted at bellsouth.net>
To: <Hallicrafters at mailman.qth.net>
Sent: Tuesday, July 13, 2010 12:09 PM
Subject: Re: [Hallicrafters] Very slow warm-up for SX-62


> I've taken Carl's advice to heart and unplugged the radio. Before I did 
> that
> I noticed that the warm-up time had decreased - that part is actually near
> normal now.
>
> I am basically a first-timer when it comes to tube type radios (I did 
> recap,
> without creating any sort of disaster that let the smoke out of the radio,
> an SX-100). But I do not want to cause any harm and since Carl says the
> SX-62 is difficult and not a job that a first-timer should tackle I'm at
> sort of a pause now. I'd like to do the work myself and think - if I take 
> my
> time - I can. But, for the moment, the radio is just sitting on a shelf
> amongst a few other old Hallicrafters.
>
> I truly appreciate those who have written with advice on this thing. It's
> fun to learn and I'm taking all the advice to heart.
>
> Bill KQ4YA
>
>
> ----- Original Message ----- 
> From: "Todd, KA1KAQ" <ka1kaq at gmail.com>
> To: "Carl" <km1h at jeremy.mv.com>
> Cc: "Bill Husted" <bhusted at bellsouth.net>; <Hallicrafters at mailman.qth.net>
> Sent: Tuesday, July 13, 2010 11:52 AM
> Subject: Re: [Hallicrafters] Very slow warm-up for SX-62
>
>
>> On Sat, Jul 10, 2010 at 12:42 PM, Carl <km1h at jeremy.mv.com> wrote:
>>> Unplug the radio and do a full recap as well as checking for out of
>>> tolerance resistors. Otherwise you risk burning up the power and audio
>>> transformers.
>>>
>>> This is the hardest, along with the similar SX-42, Hallicrafters to work
>>> on.
>>> Its not for a first timer.
>>
>>
>> SX-28 is a bear, too!
>>
>> After doing as Carl suggests (especially the audio output and power
>> supply circuits), go to the tubes. Weak tubes can indeed cause low
>> audio, but so can a mismatch in speaker impedance. They can also cause
>> the slow warm up symptoms you describe as it takes them longer to
>> build up some level of functionality due to their depleted condition.
>>
>> A tube tester is excellent for checking things like dead shorts, gas,
>> and so on, but won't necessarily guarantee a 'good' tube. Couple years
>> back I had some issues with a 75A-4 after changing a weak tube with a
>> NOS JAN replacement. I checked it twice on the tester, it looked
>> great. It was only after I placed another tube in its place that the
>> radio worked properly again.
>>
>> ~ Todd,  KA1KAQ/4
>
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