Thanks Ian!
73, Roger (K8RI)
On 4/26/2017 3:38 AM, Ian White wrote:
K8RI wrote:
At close to 200W per device, it would require 8 devices in a circuit
much like the Yaesu Quadra, but with a legal limit out for less money.
BTW I saw several posts praising the Quadra, but the Quadra has several
inherent problems in the basic design according to the Yaesu news
groups.. One is the PS is designed for 220 VAC and not the current
standard of 240 leading to a number of failures. Another is the way the
power supplies feed the individual amps. OTOH it is a nice amp and I do
see a number of hams claiming to be running 1200W out for many years.
I
have two.
The main problem with the Quadra PS is its tendency to blow the
step-start resistors (R2A, B, C) that limit the startup surge current.
This is caused by two design errors, both of which can easily be
rectified at repair time.
1. Step-start resistors are overloaded by design, but the cement-cased
resistors that Yaesu selected are quite poor at handling surges! If they
fail, replace all three with glass-coated resistors with better
surge/overload characteristics.
2. If the step-start relay fails to activate for some other, unrelated
reason, then the step-start resistors *will* blow because they have no
other protection. Following an idea from Alpha, insert a time-delay fuse
that is rated to blow in several seconds. (This idea will not work with
the existing Yaesu resistors... guess why.)
73 from Ian GM3SEK
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