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substitute for PL172




 
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Author Topic: substitute for PL172  (Read 4337 times)
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Tom W2ILA
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« on: March 04, 2005, 02:20:30 PM »

My neighbor wants to donate a fairly beat Hallicrafters HT33 linear to me.  It has a HB outboard power supply and in general has been played with.  He says the tube is beat and the PL172 is of unobtanium.
Has anyone tried a 4CX1500 converstion for old PL172 circuits?  The specs look reasonably close.  There is plenty of room etc etc.
I dont really need another project but if its free its for me.
Ideas?

TM
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K1JJ
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"Let's go hiking in the woods, Tommy!" - Yaz


« Reply #1 on: March 04, 2005, 02:54:58 PM »

Quote from: Tom W2ILA
My neighbor wants to donate a fairly beat Hallicrafters HT33 linear to me.  It has a HB outboard power supply and in general has been played with.  He says the tube is beat and the PL172 is of unobtanium.
Has anyone tried a 4CX1500 converstion for old PL172 circuits?  The specs look reasonably close.  There is plenty of room etc etc.
I dont really need another project but if its free its for me.
Ideas?

TM

Hi Tom,

Since you said it has an outboard power supply now, I would gut the old power supply, including the string of VR tubes used for the screens. [I owned one myself years ago and did just that]

You now have plenty of room to grow in there.

I would then put in a pair or triple 3-500Z's -  or some other hi-mu GG triode.  Simplicity and clean.  a 3CX-1200, 8877 -  the possibilities are many.

73,
T

BTW, I had someone today tell me that my email print type is too small when received. I tried sending it in enlarged font, but it goes back to 8pt. when sent out. Anyone know how to increase the font in Outlook Express that will stick when emails are sent out?  I tried the options page, but they don't seem to do the trick.
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WA1GFZ
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« Reply #2 on: March 04, 2005, 03:34:33 PM »

Tom check the grid specs I think it will work but a triode would be easier.
Murphy Surplus has 3CX800s A pair would rock.
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Steve - WB3HUZ
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« Reply #3 on: March 04, 2005, 03:43:33 PM »

Get rid of Outlook Express. It's a security nightmare and as you can see, functionally it sucks too. Next you'll tell us you are using Internet Explorer.

Try Eudora or Thunderbird.
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Tom W2ILA
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« Reply #4 on: March 04, 2005, 04:00:12 PM »

Good ideas all around.
The only reason I was thinking 4cx1500 was ...I have them in stock awaiting an unknown project. But you're right Tom, Frank with all that deck space there can be a boatload of configs.  I still have to see what bits are still  in there, what was torn out etc. before the plan comes together.
So many projects....

TM
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WA1GFZ
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« Reply #5 on: March 04, 2005, 04:04:16 PM »

Tom,
Just check the grid dissipation on the 4CX1500s. Go for it.
Plenty of mil rigs used the 1500. Heck drop a pair of them in.
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