[Hammarlund] BBODs in SP600

[Joe Connor]

With my first SP-600, I was in the same position as Wes. The set performed well even with an RF deck full of BBODs. I was on the fence about going through the trouble of removing the RF deck but I bit the bullet and replaced all the BBODs. When I fired it back up, I was shocked at how much better it performed, even though I thought it was playing well before. After that, I change out every BBOD or wax paper cap in every boatanchor I work on. Lesson learned.

Joe Connor



On Thursday, January 16, 2014 8:46 PM, Al Parker <anchor at ec.rr.com> wrote:
 
Hi Wes,
>    It's great to hear when good advice gets confirmed.  The Simpson, or 
>any normal VOM, VTVM, digimeter, etc, only put 9vdc on things to measure 
>resistance.  You found out what the receiver sees when it puts 
>200-400vdc on them, lotsa leakage.  I've done as you, ckd with the Fluke 
>when I take them out of an SP-600, or other, and later check them on my 
>bench megger, which can go to 1kv.  Usually it sees maybe half a megohm 
>at 200-250 volts, often at much less voltage, and often much less 
>resistance.
>    The BBOD's will get that way whether the rcvr was used or not.  And 
>that's why you should check all resistors, particularly dropping or 
>decoupling resistors.  If they've got a leaky cap downstream from them 
>they've probably been overheated for a long time and have drifted high 
>in resistance.  Then the downstream voltage, e.g. to tube screens, will 
>drop, and the tube gain wills suffer, along with the rcvr's overall 
>performance.
>    Your SP-600 should proved many more yrs of good perfomance.
>73,
>
>Al, W8UT
>www.boatanchors.org
>www.hammarlund.info
>
>"There is nothing -- absolutely nothing -- half so much
>worth doing as simply messing about in boats"
>Ratty, to Mole
>
>
>On 1/16/2014 7:31 PM, wes bolin wrote:
>> I kept the Black Beauties Of Death that were replaced when I went through my
>> SP600JX26.  And, I just fixed a Heathkit TC-2 Capacitor/Resistor tester to
>> work
>> again after who knows how many years. I decided to test the BBODs for
>> leakage.
>>
>> I tested 50 of them and every one was leaking at less than 200 volts.
>> These had
>> measured reasonably good with my Simpson VTVM Ohmmeter ie. some with many
>> megohms of resistance.
>>
>> Several contributors advisde me to replace all of them (the radio was
>> working good) so I did it and am glad they told me to do it.  I recommend
>> it too.  And, the radio has been working great for about 6 months now.
>>
>> FYI
>> Wes
>> ________
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