[Hammarlund] BBODs in SP600

[Al Parker]

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
> ________