Check your voltage "TO" the pass transistors. If it's high the
transistors will run hot. IIRC the VS and RS use the sane control
circuit, but it's been quite a while since I had one apart.
Please NOTE the Green wire is not neutral! It is a true ground, or
"earth" connection. Never, ever treat it as neutral. Your power cord
should also have a green.ground / earth AND a neutral (White) wire. If
it is one of the newer modular cords, it goes to the round pin below the
hot (larger blade) and neutral (smaller blade) . I don't know if the
newer Astrons are using those cords, or are still using direct wired
power cords.
73
Roger (K8RI)
On 1/28/2015 9:50 PM, Gary Smith wrote:
Gentlemen,
Thank you all so much for the replies regarding upgrades, suggestions
and green wire dealings with my two Astron power supplies. The only
reason I asked that here was the mention of the green neutral being
left in a floating condition on at least some of the Astron PS. I
need to repair the one that is Kaput and am looking around for a
LM723 around here as the links mention that to be a common culprit,
I've used them before in several projects and probably have several
gathering dust in an old Radio Shack package. If not, I see them
listed quite inexpensively on ebay and will pick up several for
future issues I may encounter.
The four 2N3771 transistors really do run hot on the VS-35M, can't
say I touched them on the RS-35M but surely they are the same, the
circuit between the two PS are very similar. I'm assuming I can use
any off the shelf 2N3771 & the .05 5W wirewounds will balance them
fairly. On the PS I made some years back I used 3055's and I have
several of them unused, would these be more rugged or should I stick
with the 3771 as it comes with?
Mention was made of Arctic Silver; I have some Arctic Silver 5 & some
of their Ceramique which I too used in overclocking computers. I can
certainly remove & replace the heat sink compound with this, not a
big job and using it did lower my core temps on the computer
processor.
I really appreciate the links and help.
Thanks & 73,
Gary
KA1J
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