[Hallicrafters] Alligator wrestling in the Swamp

[Carl]

Depending upon how creative you want to get a lot of heat and weight can be 
eliminated.

For the PL-172 Id toss the oil cap, filter choke (ground the center tap), 
and 3B28's.

Use about 20-25uF of total filter C and plug in a pair of those 866/3B28 SS 
replacements or wire in a bunch of 1N5408's underneath.

Seperate the 120VAC inputs and run individual line cords for T-1 and T-2. 
Rewire so T-1, F-1, B-1, SW-2 are completely seperate from T-2.

Hook a small Variac to the T-2 line and set for the correct no load HVDC. 
Measure the voltage difference and look for a suitable high current 
transformer with close to the necessary secondary voltage. Wire in bucking 
mode. Just the secondary winding needs to handle the full current so 15A 
will be fine for SSB/CW. This can be external to keep the weight down.

The other option is a standard size 18A variac in place permanently.

Do not decrease line voltage on T-1 unless the filament voltage is excessive 
and then treat that as a seperate issue.

Replace both electrolytics in the bias supply no matter what you do.

Blasphemy is good when it comes to extending the life of an obselete 
product.

Carl
KM1H


----- Original Message ----- 
From: "John King" <k5pgw at yahoo.com>
To: <hallicrafters at mailman.qth.net>
Sent: Monday, November 07, 2011 9:45 PM
Subject: [Hallicrafters] Alligator wrestling in the Swamp



Howdy folks. There has been some discussion of the Hallicrafters HT 33A on 
the list over the last few days.

Down here in Louisiana we find ourselves faced with wrestling an Alligator 
every now and then. That is a job because they are big and have nothing to 
grab onto. Thirty minutes of wrestling an alligator is like working on a 
Hallicrafters HT 33A for two hours.

I bought a HT33A about five years ago in Chambersburg, Pa. near Gettysburg 
and it has been on the shelf since I got it home. When I bought it, I knew 
that the HV capacitor in the power supply needed replacing because there was 
heavy/sticky PCB oil
 everywhere. I am going to replace the capacitor tomorrow.

I have some oil filled caps but an thinking of using series electrolytic 
caps on a board in place of the oil cap. Not original, but dependable.

This amplifier
 is so covered with tar and nicotine that I thought the chassis was GOLD 
anodized like the old WRL Galaxy 1 transceiver. I put cleaner on it with a 
brush and the gunk slid off on the floor and the result looks like burned 
motor oil out of a diesel engine.

The amplifier is a monster and picking it up is like picking up a very large 
rock. I think at my age, I need a forklift in my shop. I believe what little 
manhood I had just got up and went. 160 pound amps will strain you and 
Grandmaw.

What do you think of eliminating the oil filled cap and taking the 
electrolytic route. I know, I need to repent for such blasphemy!!! 73, John, 
K5PGW

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