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THE AM BULLETIN BOARD => Technical Forum => Topic started by: xe1yzy on March 08, 2005, 09:55:37 PM

Title: BC-610-E Restoration progress
Post by: xe1yzy on March 08, 2005, 09:55:37 PM

Im start today to disassambling one of the BC-610-E, Im going to make a good sandblast in the cabinet panel and the 3 chassis, the modulator reactor L4 are lost in both units, and also the vacuum capacitor in the rf deck, all the rest looks complete.

Im going to start with the P.S. restoration, it is advisable to go " solid state" ?

Im also like to improve the rf deck, with a VFO capability, I dont like to trust to much in the " jesus stick" in each adjust  :? .

any idea or tip will be appreciated .

Thanks in advance guys!

Title: BC-610-E Restoration progress
Post by: KL7OF on March 08, 2005, 10:08:06 PM
Pedro,,,,Congratulations on the BC 610.......I like to solid state the power supplies in my big rigs.....I use the big K2AW diodes .....they are available in many values, are bullet proof and take up much less space than diode strings.........Steve

Title: BC-610-E Restoration progress
Post by: W2VW on March 08, 2005, 11:46:07 PM
Hi Pedro,

   A wise old man who hacks a lot on the air once described how to cook high Voltage power transformers into service after they sit around for a long time. The enemy is moisture and sometimes if you don't cook out the moisture, the transformer will fail after a short time. What you want to take the plate transformer and short out the primary (which is the 110 side in your case) then apply 110 volts from the wall socket across the whole secondary. This normally produces a few hundred Watts worth of heat.  You might want to use a variac and carefully measure current  with certain transformers in order not to break stuff. If you don't get the thing to warm up then use 240 Volts.  Let it cook for a few days.

Title: BC-610-E Restoration progress
Post by: w3jn on March 09, 2005, 08:41:07 AM
By all means solid-state the power supplies, and BAKE THOSE TRANSFORMERS AND CHOKES!!  With Mexico City's low humidity, I would think that laying them out in the sun for a couple days might do the trick.

ALthough the glow of 866 mercury vapor rectifiers is cool, those miserable tubes have burned out many a power transformer when they flash over.  Also they are prone to creating RF noise.  A good sub, if you don't have solid state replacements handy, is a 3B28 xenon rectifier.  Direct sub for an 866 but won't flash over.

73 John

Title: BC-610-E Restoration progress
Post by: xe1yzy on March 09, 2005, 11:02:04 AM
Steve, Dave and John

Thanks, then I go solid state in the P.S., yes Im going to make a good BAKE in those transformers, and before that some electrical test to each one, an put some voltage for a while, yes Mexico city is normally dry, arround 30% of R.H. all year, execpt of course in the rainy season.

But this transmitters were storaged for many many years, its amazing the amount of dust!

About the 866's, yes they glow cool, but I know they are also a trouble makers, in my first viking restoration I replace those tubes with the 3B28, and works very well.

well guys, then Im going to cook some " Transformers au solei "  :)  

many thanks!
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