[Heathkit] sb-610 quad section cap

[Bob McGraw - K4TAX]

Don't forget about the HV caps.  Mouser has suitable replacements.  Number 
is 5984-940C16P15K-F and sell for about $4 ea.  These are 0.15mf @ 1600V 
units.  Failure of one of these can cause failure of the HV winding on the 
xfmr.  That's not good.

73
Bob, K4TAX


----- Original Message ----- 
From: "Mark K3MSB" <k3msb at hughes.net>
To: <heathkit at mailman.qth.net>
Sent: Tuesday, July 10, 2007 10:42 PM
Subject: Re: [Heathkit] sb-610 quad section cap


> 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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>> dfischer at usol.com **         $$ See the vintage area on the HCI web 
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>>
>
> _______________________________________________
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> dfischer at usol.com **         $$ See the vintage area on the HCI web site - 
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