That's right, Joe -- the Molex connector must be fully inserted and
inserted correctly. Like most Molex, I don't think it's possible to
insert it wrong.
I just looked at the schematic to refresh my memory. That
multi-conductor cable carries the power interlock, filaments, the 28V DC
supply, and 120VAC to run the fan. Check my schematic. The interlock
goes through a micro-switch under the cover of the PSU and another under
the rear cover of the RF deck.
See my notes on the schematic about failures that can fry traces in the
28VDC section of the power supply. Also, there's a 4A slow blow in the
surge protect circuit. It's inside the PSU. And there's a 1 ohm resistor
in series with the 28VDC line that serves as a fuse for the 28V bus.
I have three vintages of 425s here. All have the main power switch on
the RF deck (it's the bottom switch).
My schematic does NOT include details of the RF circuitry around the
tubes (LPF at input, and the tank circuit), and there are variations
from one vintage to another.
http://k9yc.com/Titan.pdf
73, Jim K9YC
On Tue,10/25/2016 11:49 AM, Joe Giacobello, K2XX wrote:
I've sold my Titans, but besides the HV cable you need the low voltage
cable between the P/S and RF deck. IIRC, the power switching is done
through that cable. (Make sure the green dot faces up when you plug
the cable into the Molex socket.) Also, IIRC, there is a power switch
on the P/S together with voltage selector and fan speed switches.
Some of the earlier units may not have had the voltage selector or fan
speed switches.
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