[Heathkit] sb-610 quad section cap

[GDM]

Antique Electronic Supply has new manufacture, multi-section 
electolytics in FP type cans.  I don't about physical size, but they do 
have the right values and voltages you are looking for cost.  Cost is 
$30-35 each.  For the most part, these are NEW, not NOS.

73, Gary  W9OAK

Jim Brannigan wrote:
> On the electrolytics:
> Cans are not made anymore.  A few fellows make specialized items for a 
> few radios.
> The 610 can is too small to be "stuffed" with new components, so you 
> will have to use discrete components.
> 40ufd @ 500VDC is fine.
> 
> Replace the diodes, they are prone to fail short.
> 
> It is good practice to replace all the resistors in the HV section of 
> the scope.  They tend to drift higher in value.
> 
> With the above accomplished, you can see if the device needs more TLC.
> 
> Jim
> 
>> Hello all,
>>
>> I've been slooowly working on an sb-610.  I am looking to replace the
>> 4-section twist-lock capacitor can, part number 25-63. It is listed in
>> the parts section as having 30ufd, 20ufd, 20ufd, 20ufd.  There is no
>> mention of the working voltage.  These 4 sections are handling a maximum
>> voltage of +265V in the power supply section.  So I have a few
>> questions.
>>
>> 1. When looking for a replacement, are these twistlock style cans come
>> in different mounting sizes? I don't want to get one that won't
>> physically fit. Does anyone know what "size" I should look for?
>>
>> 2. Can anyone determine looking at the power supply circuit diagram if
>> there is any problem increasing the capacity of all 4 sections? Would
>> there be harm in doing 50ufd for all 4 sections? Might this raise the
>> corresponding voltages somewhat and might that not be good? Or, when
>> filtering rectified AC, the bigger cap the better? But then, why would
>> heathkit specify different capacities for each section? Why wouldn't
>> they just do 40/40/40/40? What about Working voltage? Is 500VDC enough?
>>
>> 3. Does anyone know what an "acceptable" amount of ripple would be on
>> any of these sections? I am seeing some odd things that may a) mean my
>> caps are bad in the can or b)I am supposed to see what I am seeing and I
>> just don't know any better!
>>
>> For example. On the semi-circle section of the cap, when viewed on my
>> scope (in ac-coupling) I see a perfect descending ramp pattern where
>> Vp-p is about 4v.
>> Other sections have some crazy 2.5Hz .6vp-p waveform with a 60Hz .4vp-p
>> ripple super-imposed!
>>
>> Should these sections be plain old dc with limited ripple? If not, then
>> it would seem like the values of these sections are important. If it
>> should be plain old dc, then it would seem that the capacity values are
>> less important (can be bigger), no?
>>
>> ----
>> Other questions.
>> 4. Should I replace all diodes? D1-D4 are silicon D5 and D6 are
>> selenium. Do I understand that selenium should be replaced as a matter
>> of good practice? These are handling some very high voltages, if I were
>> to replace them, what would I use?
>>
>> 5. I know that it is good general practice to replace the electrolytics,
>> but what about the micas and ceramic discs? Assuming I have no specific
>> problems with any of them, do they fail? Or should I only change them if
>> they fail?
>>
>> Mucho thanks in advance!
>>
>> Eugene
> 
> 
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