Re: 545 HV won't oscillate 100% of the time.


Don Black <donald_black@...>
 

I'm not so sure. Yours may be faulty, these are tested good so they must be a rare animal.

Don Black.

On 08-Dec-13 2:31 AM, Daniel Koller wrote:
 

I'll check and see what's in there.   And when I take them out, I'll sell them on e-bay to an audiophool!!
http://www.ebay.com/itm/4-TUBE-AMP-CAPACITORS-0-1uF-400V-Sprague-Bumblebee/171185528791?_trksid=p2047675.m1982&_trkparms=aid%3D333005%26algo%3DRIC.FIT%26ao%3D1%26asc%3D177%26meid%3D3232141210003616509%26pid%3D100009%26prg%3D1088%26rk%3D1%26rkt%3D5%26sd%3D181276706729%26

(No affiliation with the seller!)

Dan

On Friday, December 6, 2013 11:27 PM, Chuck Harris wrote:

>Most of the time with the 545, the problem is the black beauty oil/paper
>tubular capacitors used for the HV filters.  They always go bad, and if
>they haven't been replaced, you must replace them.  Ceramic is fine.
>
>There is also a BB cap that is in series with the grid feedback winding,
>and another in parallel with the plate winding.  Both must go.
>
>-Chuck Harris
>
>Daniel Koller wrote:
>> Howdy,
>>
>> The recent discussions on HV repairs has me thinking I should look into the issues
>> in my 545 (not A or B, old style square case).   It works very very well, but
>> about half of the time, increasingly more, the HV circuit will not oscillate.  If
>> I pull the plug-in out and drop it back in, it will work.  I know this is not a
>> recommended option!  Alternatively, if I shut it off and wait for it to cool, it
>> will work when I turn it on with about the same probability, or a little less.
>> Once the scope is on it's up to spec.
>>
>> The 6AU5 is not brand new, but is good.  It was replaced recently with no
>> improvement.
>>
>> So, suggestions as to where to start on this intermittant problem are welcome.  Is
>> there anything I should look for or measure that might indicate what is getting
>> tired?
>>
>> Dan
>>
>
>
>
>





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