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T-195 tips, suggestions




 
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AA4HA
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« on: December 31, 2012, 09:34:03 PM »

I picked up a T-195 (not A, not B) with a companion R-392 and would like some tips on the T-195 transmitter. I plan on going over the transmitter from top to bottom before firing it up and understand that there are some upgrades/ modifications that can be done. I have the maintenance and operations manuals and went through the theory.

The transmitter and receiver are currently operational so they "should" be in decent shape.

I am good with the R-392, I have quite a bit of experience with the R-390 and the R-390A.

Does anyone have any guidance to offer?

thanks,
Tisha, AA4HA
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WQ9E
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« Reply #1 on: January 01, 2013, 09:48:43 AM »

Tisha,

I have no guidance to offer but please share your impressions about the T-195 once you have it going.  I have been tempted several times to acquire one to go with my R-392.

If you have not read them already take a look at the ER in Uniform article in Electric Radio for December 1997 and the three part design series in the Sept-Nov 1998 Electric Radio issues.
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Rodger WQ9E
N8ETQ
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Mort


« Reply #2 on: January 01, 2013, 09:50:39 AM »


  Hi,


       I had one for a while, they work great
as is. Later models had an inverter for the TX
HV versus the dynamotor but either one works
fine.

       The TX will load a 20' whip through out
it's coverage range however if you have a set
of Military Cans on you may get an RF burn on
your ear on 160 m.


      You may want to run the R392 from a
seperate 28VDC supply as the TX will really
haul down current when the dynamotor starts.

GL

/Dan
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AA4HA
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« Reply #3 on: January 01, 2013, 10:17:19 AM »

Dan,
Thank you for your reply. I do plan on running the R-392 off of a separate supply as it would not mind running at 24VDC. I understand that the T-195 prefers a higher voltage (~28VDC) so the auto-tune will work correctly.

A few things on my list so far;
  • Tubes, obviously, if something it bad I have spares for everything but the 4X150d (set on order, I always keep spare tubes for everything).
    Clean all of the mechanical gears, bearings, bushings and re-lubricate with synthetic oil.
    Repack the dynamotor bearings and where possible, the tuning motors with synthetic grease (since they probably have never been done).
    Check all of the caps for leakage and value changes (gives me a reason to use the Sencore LC53).
    Check all of the resistors for cracks/ value changes.
    I will preemptively change out anything that is a black beauty (BBOD) or a 60 year old electrolytic.

Are there component value changes or circuit mods that I should consider? I know that the T-195 is different than the T-195a or T-195b. I have not found anything that explains those differences. I understand that the later revisions draw less current and if I can realize that advantage I would like to do it while the case is open.

I am willing to consider all suggestions,

thanks,
Ms. Tisha Hayes, AA4HA
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N8ETQ
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Mort


« Reply #4 on: January 01, 2013, 11:00:17 AM »


Hey Tisha,


    Well the only thing you can do to keep the
Current and noise down is try to find the SS HV
supply.  They look exactly like the dynamotor
and it was a plug and play swap. Keep your dynamotor
however as the SS thing is pretty much unrepairable
since all the components are sealed in with
some sort of "Goo".

    As I recall they sounded pretty good in "RELAY"
mode since that bypassed the Carbon Mic speech amp.
They used to feed line level audio in to that.

   Here's a pix of mine prolly circa 1990 or so.
I still have a TX/RX mount in my garage I picked up
somewhere you can have it if you need it.  The only
complaint I ever had about the thing was the noise.
Mine also had the HV Dynamotor.

73

/Dan


* GRC-19.jpg (178.22 KB, 1264x880 - viewed 424 times.)
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KA3EKH
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WWW
« Reply #5 on: January 01, 2013, 12:54:37 PM »

The start up current requirements for the transmitter can be an issue, your going to need a huge power supply. The newer versions of the 195 had the solid state inverters that were a direct replacement for the two dynamotors and were not quite as bad as the dynamotor version. The only dynamotor version I have seen in operation required a set of car batteries in line with the power supply in order to get it started. The auto tune system is a thing of beauty when working but sometimes fails and you have to let the radio try to tune again. I have my old M151A1 out in the garage and have thought about building up a GRC-19 (R-392/T-195) and stuffing it on the back but have decided that if anything will go with a newer set maybe something like a GRC-106 or one of my newer Harris sets being they are smaller, lighter and for me easy to work on, good luck and start rounding up heavy gauge wire and lots of 28 volts.
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AA4HA
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« Reply #6 on: January 01, 2013, 02:31:15 PM »

I am going to keep an eye out for the solid state inverter for the 1000 VDC supply. If I cannot find one I may make my own, just getting 500 mA at that voltage is going to be challenging while keeping it in the form-factor of the dynamotor space.

I already have a pretty stout 27.3 VDC bus setup for the other mil gear I operate. It is a 225 A/Hr battery bank with a 50A switching supply to keep things charged up and peaked up.
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N8ETQ
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Mort


« Reply #7 on: January 01, 2013, 06:59:47 PM »



  Set "Way Back On",

       I think the LV dyno supplied the 400cy AC for
the tune motors.. Brain Clogged pretty gud about Now..

/Dan
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N8ETQ
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Mort


« Reply #8 on: January 01, 2013, 07:33:33 PM »



Posted by: KA3EKH

"The start up current requirements for the transmitter can be an issue, your going to need a huge power supply. "

    Hey Man,


    That may be the first "Understatement of the year" for 2013!!

I had 2 X 28VDC Lamda supplies 30A each. Had to
disable the Over Current thing on both of em..

   Pretty "Manly" radio there Trisha, I think you'll
be Ok.

/Dan

   Pix of my "New" dog Mort.   She is standing on the
front fender of my Bud's M35A3 duece and a half
scanning the tree line for pesky tree rats..


The start up current requirements for the transmitter can be an issue, your going to need a huge power supply. The newer versions of the 195 had the solid state inverters that were a direct replacement for the two dynamotors and were not quite as bad as the dynamotor version. The only dynamotor version I have seen in operation required a set of car batteries in line with the power supply in order to get it started. The auto tune system is a thing of beauty when working but sometimes fails and you have to let the radio try to tune again. I have my old M151A1 out in the garage and have thought about building up a GRC-19 (R-392/T-195) and stuffing it on the back but have decided that if anything will go with a newer set maybe something like a GRC-106 or one of my newer Harris sets being they are smaller, lighter and for me easy to work on, good luck and start rounding up heavy gauge wire and lots of 28 volts.


* mort 004.jpg (1214.65 KB, 3648x2736 - viewed 426 times.)
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