[Heathkit] sb-610 quad section cap

[Mark K3MSB]

But for about half the price,  you can get 4 new individual ones from 
Mouser and stick them under the chassis and disconnect the original FP 
and leave it for effect.  Works well, and is a reversable mod for the 
purist.

 >>but what about the micas and ceramic discs?

I wouldn't worry about the disc ceramics unless you visually see 
evidence of an issue.   The exception to that,  at least for me, are 
those that are used for line bypassing applications.   I typically use 
3KV for those,  most of the ones I've seen in Heathkits are not that big.

73 Mark K3MSB
 

GDM wrote:
> 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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> _______________________________________________
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