Having problems with a SPECTRUM 4000 UHF repeater that the voltage regulation
works ok on RX, but when you kick it into TX, the SCR fires and blows the fuse
or frys the resistor.
This is the newer version power supply board that has the current limit control
on it.
We replaced the SCR and .25
Could it be RF triggering the SCR?
Jerry W9FS
- Original Message -
From: Ed
To: Repeater-Builder@yahoogroups.com
Sent: Thursday, October 15, 2009 9:17 AM
Subject: [Repeater-Builder] Spectrum UHF Repeater SCR Crowbar circuit
activating during TX
Having problems
I had a similar problem with a home brew supply.
My fix was a choke (100 uHy)in series with the gate as close to the
gate a possible.
I bypassed the choke on both sides with 0.01 uF capacitors with leads
as short as possible.
This fixed my problem.
You are probably rectifying RF inside the SCR.
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