Hallicrafter 8R40

8/2/2009 1:57:26 PMCharlie Griffin

I am a bit puzzled, and was hoping someone out
there could help me out. on the Hallicrafter 8R40
where the 5Y3GT rectifier tube is suppose to be, there is what looks like a electrolytic Capacitor. is this
the tube...? or is it possible, this Radio was
Modified..? any Answers would Be of help to
Me. Thank You, and 73's to All. KC9KDO...Charlie

8/2/2009 2:38:37 PMEdd

Sir Charlie. . . .

First, look inside of the set just towards the front of the chassis from your "5Y3" rectifier tube position and see if
a large alumininny-i-yum-yum canned electrolytic is still present.

You then see if the mystery "5Y3" will unplug.

If so, a former owner invariably replaced the 5Y3 with a solid state equivalent, it's saving 10 watts of filament power
loading of the power transformer as well as being much more c o o o o o o l running.

73's de Edd

8/2/2009 2:52:04 PMWarren

Charlie : Edd is right about that. I like to make my own solid state full wave rectifier, with the use of an old tube base. Cuts down on all that heat, makes the Hallicrafters happy.

8/2/2009 3:33:34 PMCharlie Griffin

:I am a bit puzzled, and was hoping someone out
:there could help me out. on the Hallicrafter 8R40
:where the 5Y3GT rectifier tube is suppose to be, there is what looks like a electrolytic Capacitor. is this
:the tube...? or is it possible, this Radio was
:Modified..? any Answers would Be of help to
:Me. Thank You, and 73's to All. KC9KDO...Charlie
:

8/2/2009 3:42:31 PMCharlie Griffin

:Thank you Gentlemen,for your responses.
I took the chassis out of the case. I can see
where there was a tube socket riveted in at one time.
it has long since been removed, and a Electrolitic
Cap. Put in its place. there is a Electrolytic
in front of that. that is on the schematic.C-27.
Now I have to Decide what to do with it. I got it cheap,But I do Love the Hallicrafter Radios. I now Have 14 in all.any Gusse's to why this would have been done? and is it recommended to put it Back to Original?
Thanks Again, for the Help. 73's KC9KDO...Charlie

8/2/2009 4:19:53 PMNorm Leal

Hi Charlie

A solid state rectifier doesn't have filaments so it saves 10 watts of heat.

There are a couple disadvantage. A solid state rectifier will supply higher B+ voltage as the drop within a tube is eliminated. A solid state rectifier doesn't have a delay bringing up voltage. A tube is delayed buy requiring filaments to light first but 5Y3 doesn't have much of a delay.

Either way will work. Be sure voltages don't exceed capacitor rating when using a solid state rectifier. I would tend to leave a tube in the circuit if the proper one was available. A 5Y3 is common.

Norm

::Thank you Gentlemen,for your responses.
:I took the chassis out of the case. I can see
:where there was a tube socket riveted in at one time.
:it has long since been removed, and a Electrolitic
:Cap. Put in its place. there is a Electrolytic
:in front of that. that is on the schematic.C-27.
:Now I have to Decide what to do with it. I got it cheap,But I do Love the Hallicrafter Radios. I now Have 14 in all.any Gusse's to why this would have been done? and is it recommended to put it Back to Original?
:Thanks Again, for the Help. 73's KC9KDO...Charlie
:

8/3/2009 4:43:08 PMEdd

Sir Charlie . . .

W E L L, if you are finding an additional filter hard wired in the 5Y3's former position, you should also be finding a set of SS rectifier diodes . . . . 1N4007, etc . . . . . mounted on a terminal strip under chassis. Don't know their logic for the extra filtering , however.

If you are uncertain as to what was done, a close up photo of the underchassis new parts and wiring in that very select area probably would help in making an analysis of their mindset for making the change.

73's de Edd

8/27/2009 3:51:09 PMLes Layton

The early versions of the 8R40 used a selenium rectifier and voltage doubler circuit instead of a 5Y3. The transformer is also different as it doesn't have a 5 volt filament winding. There are two capacitors on top of the chassis, one is a large wax type , the other is a smaller electrolytic. Later in production Hallicrafters changed to the tube type rectifer. Maybe to keep more parts in common with the S-40 series?
The SAMS photofact I have shows the early version with the selenium rectifier and I own one in that configuration.

::I am a bit puzzled, and was hoping someone out
::there could help me out. on the Hallicrafter 8R40
::where the 5Y3GT rectifier tube is suppose to be, there is what looks like a electrolytic Capacitor. is this
::the tube...? or is it possible, this Radio was
::Modified..? any Answers would Be of help to
::Me. Thank You, and 73's to All. KC9KDO...Charlie
::
:

8/28/2009 1:39:31 PMEdd

Sir Charles. . . .

With the last info coming forth from Sir Les, I pulled this info, should you need its info / data in the future, or to just further fulfill upon your current query.

73's de Edd

HALLICRAFTERS 8R40 Pictorial and Schematic Info: