Tuesday, January 19, 2010

Alpha 78 Arrives from AZ

Alpha 78 arrived yesterday from AZ. 1st inspection looks like it survived the UPS trip ok. According to K5VT this amp has made several trips to Africa with the Voodudes "That amp did some time in VP5 before I got it and then we had it in XT2 for 2 contests and TZ got two contests. I love it when the gear has a bit of a 'story to it'  http://www.voodoocontestgroup.com/.  It looks a bit rough but if it runs ok it will be a useful addition to the station here.

This thing is a bit of a monster.  The transformer came in a seperate box.  The red item next to it is an auto tire gauge for size.

Wednesday, January 13, 2010

Drake T4Xb On the Air Again

The T4Xb is on the air again.  The radio was purchased along wtih a R4B, MS4 and AC4 about 2 years ago.  The R4 was working when received but failed after a few months.  Last week I found a loose rivet on the RF Gain Pot that was keeping it 3/4 muted.  After repairing the loose connection it was working well again and I deceided to unpack the T4 and give it a try.  The rig fired up and seemed to be working for about 15 min. and then the +250 V filter Cap in the AC4 'smoked'.  I replaced the twist lock dual cap with two computer electrolytics under the chassis and tested it again.  Now working sort of but only at low power levels and the plate meter was pegging at very low output like 5-7 watts.  The tubes were putting out 80 watts with the bias control cranked all the way and the meter was 'hard pegged'.  One of the guru's on the Drake list suggested looking at the meter shunt resistor which is located on the vertical board behind the three power resistors.  This resistor was found to be open and the 2.2 ohm resistor was replaced and this brought the power up to 110 watts with a more normal meter reading. The meter was still reading a good bit low though so back to the Drake Forum and it was suggested to put a 5 ohme resistor in the B- line and measure the voltage drop to set the idle current.  I had a 6 ohm and calculated that .075 A should give about .45V (Note the AC-3 had a test point here with a 5 ohm res but it was deleated in the AC4).  Then I removed R39 (on the slide switch) and replaced it with a small 0-200 ohm pot.  Adj the pot until the meter reads .075A then measure the pot and replace with closest value resistor.  Mine changed from 122 ohms to 24 ohms, not sure why but now the meter is reading correctly at the idle current point at least.  Another try on a Cantenna and by increasing the loading a bit more managed 120W output.  Still a bit low but the plate meter is correct at least and the output is in the ballpark at least.  Alignement or new driver or PA tubes is probably the next step but for now 120W is fine for my purpose.   Lots of fun to get these old things on the air again!

After working FB for a couple of weeks I did buy some used tubes on eBay for the Finals and they were weaker than what I had.  I left them in for a few days and one AM when I turned it one it started smoking after a min or two and I am still troubleshooting it again.  Should have left it alone.  The Filament fuse opened and so did R3 the 100 ohm 5W resistor in the AC4 250V B+ line.  I looked for where the smoke was coming from but just cant see it so I think it is a wire somewhere.  I hooked up the filaments and replaced the resistor with a 'test' one and the 250V line is still nearly shorted somewhere.


With much help from the 'Drake List' folks the following problems were solved.  One of the Finals was shorted and took out a screen grid resistor R30 68 ohms.  This is where the smoke 'came out'.  With the original finals back in the radio was not switching VFO's properly with the R4B and it was drawing idle current all the time.  Tube V2 was also found to be shorted Cathode to grid and was pulling down the 'transmit control' line.  After replacing V2 the rig started performing correctly.  Lots of work trying to get a few more watts out of the rig was a bigger 'learning' experience than I expected but it was a good way to spend the 'Blizzard of 2010' here in Maryland.

Thanks again to all who helped me troubleshoot this!

Friday, January 8, 2010

First Grandchild Born Jan 6 !

Lillian out first grandchild was born on Jan 6th at 3:36pm at the WVU City Hospital  in Martinsburg West Virginia.  We took a ride out to visist and spend a few days nearby.

Saturday, January 2, 2010

SKN Straignt Key Night

New Years Eve is also know as straight key night and I like to see if I can find my straight key and make a couple of contacts.  This year I worked 3 stations and one contact with KO1E Dave in RI which spanned the 2009-2010 minutes.  Dave mentioned that he was using a Begali Key that he received from his wife as a Christmas Gift.  I had to look it up and here is a picture of it.

See  http://www.i2rtf.com/html/camelback.html

This straight key stuff is 'real' old school ham radio and it is great way to spend a few min on New Years Eve or day.

Happy New Year from K3PG

Friday, January 1, 2010

Oh No! Another Amp on the way!

Hello my name is Paul and I am an Ampaholic. It began about 1980 when I bought my 1st amp it was just a GLA-1000 hey it's just a couple of sweep tubes and I can turn it off anytime I want! Who's it gonna hurt anyway? I need to be able to work that new DXpedition and ALL I have is this little wire and mini beam, who's it gonna hurt. A few years go buy and I turn the amp one once it a while to work a new one, hey I am not using it ALL the time but it would be nice to have a bit more when I really need to work that new one. Reading the paper one day a few years later I saw an ad for an old Hunter Bandit for $200 that was working. I went to look at it. Hey this guy REALLY knows his stuff and he has THREE amps. He says that this other one that I have NEVER heard of is really the best deal but it needs a little work. UH OH!? It really does look nice it has two 3-500z and a separate power supply and it is not a Drake but kinda looks like one, it is a 1969 Raytrack DX2000L. It ONLY needs a CW/Tune relay but it is 'strapped' for SSB and it runs fine, Uh how much? I stammer and I can feel my knees get weak, even though it is ALL my money I hand it over and carry it out to the car where my friend is waiting in the car. I get this home and 'strap' it up for 220 in the 'CW' position.

A couple of years go by and things are going along ok, every now and then I switch on the AMP even though I live in a townhouse! I have to work that new one. Maybe no one will notice if I keep it short! Hit the switch turn the beam...come on ....come on ...call again call one more time..YES! YES! "Got him" Yes 599 even though the band noise is horrific and but I have heard my call and report Yes! Well one night I cam calling on 40 got the big doublet loaded up on the KW Homebrew tuner with the rotary inductor and BIG caps got the amp in 'CW' all loaded up and am in a QSO when all of a sudden bang it sounded like a gunshot and parts of the meter come flying out the front of the radio and smoke comes out of the power supply! Holy Crap what the H___ happened. Well I replaced a tube, found a meter that was sort of a match and tried to make the burned meter switch work. I got it working again and life continues.

A big move takes place and we buy a new old house about 35 miles away and need to move the station. I have a 220 line put in for the amp on the 3rd floor and we get moved but I am very busy and now working two jobs not much time for radio really but I still turn it on once in a while when I NEED to. You know, well it's just sitting there waiting to be used. It's not going to hurt anything and I am now a bit farther from the neighbors, who's it going to hurt, no one will even notice it probably! Well the poor meter switch now takes a bit of wiggle to get it to work right and eventually it wont work at all and I take the station down to repaint the room.

Five years later I see the old FT-990 sitting in a corner and think heck I just hook up the exciter and listen a bit, you know see if it still works and maybe ck into to a net once in a while. Hey maybe this one contest just RTTY I can quit anything I want and hey it's just the exciter, it won't bother anyone.

One day I see an ad for someone wanting to buy Raytrack gear so I take the DX2000L out and take some photos of it and the person who placed the ad is K8ICB the original "Mr. Raytrack" now retired in Florida. Dan the designer of the Raytrack kind of encourages me to try and get it going but changing the meter switch and installing the relay is something that I have just not taken the time for so it goes back in the storage pile.

Three years later and I am now 'retired' and have the station set up but I miss having the amp to switch on when I NEED it, you know when you just HAVE to be a bit louder. I send Dan an email to see if he is still around and ask him a few questions about repairing the amp. I did have a ceramic switch that was a bit larger but would fit for the meter switch and I had a 20amp relay for the SSB/CW switch but Dan suggested using a 30A relay instead because that was the original design. I also removed some of the bias changes and put it back to the original design as much as I could. New meter switch and new SSB/CW relay to switch the HV taps and I am ready to go. Lots of testing of the amp and tubes to make sure it is solid. I did make a mistake while testing tubes and smoked the p/s so I got to replace the diodes with some hefty 1n5408's. The Heathkit Condenser Checker says the Caps are still "OK' (they had been replaced once before). Couple of new 'safety resistors' and more tube testing to get a good pair. Hey the amp can now go into SSB and is putting out over a KW and this is good.

Lots of net check in's and a little contesting with the newer FT-1000MP Mk V and it is humming along fine. I thought...until one day I see an add for a Clipperton L distress sale and I just had to buy it because it was working and had 160M on it well that would be fun to try and it's only $400 and who's it gonna hurt to have another amp, besides it will MATCH my MT-3000a tuner now that would look good and hey sometimes I operate from my 'other' location portable and well one might need a backup right? It won't hurt to have two.

Buying tubes on eBay like crazy to test for the amps. Some are broken some are good some are bad but you really NEED a nicely matched pair of 3-500z's and a quad of the 572B's. These things WILL put out a bit more if the tubes are really good and matched and you might NEED that in the next pileup right? Hey there is a an ad for someone with some parts for a Clipperton and I MIGHT need that power supply board and hey maybe he has some of those panel lights and a set of parasitic suppressors they COULD be bad or go bad and then what??

Maybe I will look at Craigs List, you know just 'in case'. No way an old Heathkit amp for $250 right nearby too maybe I'll go look at it, just for fun, you know, what could it hurt? Well on the way home with a SB-230 that was stored for over 20 years what could be wrong with it and I got it for $200 heck I could probably part it out if I 'had to' what the heck it won't really hurt anything. Well this amp had a few bad connections of push on connectors and that was it. Brought it up slowly and it works fine! It sure is quiet with no blower maybe will use it for something but it is really only 5-600 watts and no 160 or no QSK but it is pretty and works fine, tube is very strong too. Maybe I could put the vacum relay in it for fun and have a very quiet QSK amp it would be almost like solid state.

At Thanksgiving dinner I meet K1RA who says he recognized me from one of the amp lists and asked me what I had been up to. George suggested that I look into some sort of ALPHA amp as some othem worked on 160 and had QSK and are still well supported if you need anything except the tubes which might be hard to find. So when I saw an ad for a '76' I asked for the pix and thought well I am just going to 'look' right? Hey you don't have to buy so I found out that the 76's usually had regular T/R relays so I declined but THEN he said well I have this old '78' that is like a 5 that I could sell IF you want it. Well ok then I will take a look at the pix. The pix don't really look that bad and the price is right and the guy seems OK so I send the check but you know what if the tubes go bad? Then I see a set of 4 8874's on the 'auction site' and thought well I will just make a note of the ending time and see how high they go. It might not hurt to have a spare or 4 right?

Anyway I am now waiting for my 4th Amp! It won't hurt to have QSK and 160 and THREE tubes, you never know when you might need it to work that new one and hey I can quit anytime, I don't even run it all the time, who's it going to hurt anyway? Huh...?

Happy New Year

Update Dec 2012 Added a TT Centurion 422.  I added the 10M mod and some missing plastic trim.  It worked fine for a few months.  It has nice QSK and I love the Peak Reading LED's on the front.  Then the nice LED's came on at start up and stayed on.
Update Feb 2012
The Clipperton went to ME to my friend KB1OV but he had RFI issues with a neighbors phone so it was sold to another ham in NY.  Hope he enjoys it.
The Alpha 78 filament transformer connection at P1/J1 failed at the crimp and after a month or two we finally figured it out and repaired it with a 'by-pass'.