> I understand that the AL-1500 has a grid-trip circuit. The 8877 (s/n
> HSZ501)I tested this morning had gold-sputtering. It was removed from an
> AL-1500.
Alas, the grid-trip circuit in the AL-1500 limits at a whopping 175ma Ig, and
is not adjustable.
> >An 8877 has no business having over 75 ma grid current flowing for any
> >reason.
>
> Only c. 5W?
At 2250 watts output, an 8877 draws less than 65 ma grid current.
75 ma limiting is plenty of headroom. A cap sits in the base circuit
of the TIP120 to prevent nuisence trips.
> >8877's are $700 + per pop (pun intended) now from RF Parts. The above is
> >really
> >cheap insurance. Works good, lasts a long time.
> >
> Ever ran an 8877 with no suppressor whatsoever?
I have not personally, but if you look at old Orr and ARRL Handbooks,
you will see several 8877 projects sans the Supp.
(((73)))
Phil, K5PC
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