AXW - I (wife) has used a dish washer for many years and we never had the problem with aluminum that you mentioned.  It could be the detergent you are using or maybe the water itself. 

Any way when cleaning a rig in the dish washer remember it will not remove rust and /or corrosion - only dirt, nicotine residue, and oily gunk.  Once again I only recommend using a dish washer on the worst of the worst and only as a last resort when everything else has failed.

Depending on the level and the identiy of the filth, I usually spray the chassis with Crud Cutter or a similar cleaner a couple of minutes before I put it into the dish washer.  Then instead of dish washing detergent I usually just squirt some Dawn into the botton of the dish washer and turn it on.

It works.

Dick  AD4U

As a boat anchor restorer I have done this several times when all else failed and on total basket cases.  When it comes to drying the rig after its bath, I always just place the rig on a table directly in the hot summer sun for up to a week to make sure everything is dried out.  I DO NOT use the drying cycle in the dish washer.

Once I am sure everything in the rig is dry, I spray DeOxit on all pots, switches, and tube sockets before inserting the tubes.  Also you may have to put a DROP of oil on certain switch "bearings" and maybe on the PTO shaft.

Good Luck

Dick  AD4U

In the real world about the only way to tell is to plot SWR curves with each antenna mounted in its normal location with the other antenna removed.  Then do the same with both antennas mounted as you described.  If the SWR curves changed, then there is interaction between the two antennas.  If not then there MAY NOT be interaction between the two antennas.  SWR is only one of several indicators of interaction between antennas, but in the real world it is about the only one that you can test with simple measuring equipment.

Dick  AD4U

I have them all - from the 7G605 all the way through the last version of the 7000, except the military version.  They all still work.  As Zenith said, "The quality goes in before the name goes on".  If needed parts are still available.  I wonder how many of the current SWL radios will still be working in 75 years.

Dick  AD4U

3KV and 350mA = approx 1000 watts input.  You should be getting 500-600 watts output under these conditions.  If you are only getting 125-200 watts out on 20-10 meters, this is VERY POOR efficiency.  If it were mine I would look for the problem(s) to be somewhere between the tube anode to the SO-239 output connector.  Put another way I would look for the problem to be in or around the tank circuit - tune cap, load cap, coil, bandswitch, relay, and / or associated wiring.

Dick  AD4U

PS:  Make sure the wattmeter you are using is accurate.  Do you have access to a Bird 43 or similar?

Assuming you verified that all is in order per the recommendations from Ameritron, what you are seeing (decreasing output as the frequency increases) usually indicates a soft tube.  I know your 3-500 is new, but "is it good"?  Unfortunately the only to tell is to replace it with another 3-500 that is known to be good.

With proper drive power - is the plate current around 400 mA on all bands or does it drop off as the frequency increases?

Dick  AD4U

Typically it will be 20M in the daytime and 40M at night.  Of course that can (will) vary from day to day.

Dick  AD4U

Dale - Thanks for posting the video.  You and I corresponded several times about our FPM-300 MKII restoration projects.  After a year of off and on work I also got mine working great.  Ironically the VFO in mine was fairly stable after an hours warm up. 

Then I decided to replace the original HV filter caps with brand new 100Uf 450V caps I bought at the Charlotte NC hamfest.  Upon turning the rig back on after replacing the caps I got smoke and then the AC fuse blew.  I removed the PS board again and found no evidence of a wiring error.  Maybe the caps were bad.  After all replacing HV filter caps is not rocket science.  Any way I got angry and put the rig aside a month ago and started another restoration project.  Sooner or later I will get back to the FPM-300.

Last you and I talked you had power output issues.  I get (or got before the smoke) 150W PEP.  I recommended a Raytheon green banded Japanest 6KD6 which solved my power output problems.  Did the green band 6KD6 solve yours?

My FPM-300 looked almost new from the get-go, so I did not have to do any cosmetic restoration.

73  Dick  AD4U

Bill I have 3 Glaxy GT-550A transceivers.  I wanted to have a properly working one in my boat anchor collection.  Unfortunately I ran into the same problem(s) that you did.  Of course this rig was completely hand wired.   It looks like Galaxy built this rig in layers under the chassis without much thought to future access for repairs.

In each of mine the B+ resistors on most of the tubes had gone very high in value due to 40 years of age and / or heat.  Getting to them is a night mare because so many other components were installed on top of them.  While trying I broke off phenolic and wax paper formed coils and ruined the rigs.  I do not consider myself to be a klutz.

After trying to return 3 different GT-550A rigs to original working specs (mainly replacing defective resistors), all I have left are 3 nice parts rigs because I broke critical (un-obtainable) parts while trying to replace defective parts..  

Unless I find a mint working GT-550A, one of these won't be in my collection.

Good Luck!

Dick  AD4U  

Agreed..........If anybody wants to run with the BIG GUNS in HAM radio, you DO NOT do it with an Alpha 77SX, except perhaps as a driver for the big amp.

Why do you drive a car that can go faster than the legal speed limit?  It is because you drive 100 MPH every where you go??  I bought the 77SX in 1991 for $2000 because the owner had to sell it and I wanted to buy it.  I have ben offered and refused $5000.  Good investment??

Except possibly a pair of 8877's in an Alpha 77SX.  I know because I have one.   HI   

Dick  AD4U

I will admit that compared to the real experts on this site, my knowledge would not amount to a drop of water in a swimming pool.  Again...I never said an AL-80 would not put out 1000 watts PEP on some bands - it will.  I never said an AL-80 amp was not a good amp - it is.  I never said an AL-80 amp was not a well designed amp - it is.  I never said the 3-500 tube in an AL-80 amp was being driven so that its plate dissipation was being exceeded - it is not.  Actually I think the AL-80 offers (by far) the best bang for the buck on the market today.

When I studied EE in the late 1960's every amplifying device (tubes, transistors, and otherwise) came with a set of characteristic curves that showed what could be expected of the device under different operating conditions. Most of these curves were never a straight line for their entire length.  Typically the curves tapered off, even "wiggled" at some points along their length, but especially toward the high end of the curve which equates to maximum plate or collector current.  Depending on the application sometimes that mattered and sometimes it did not matter. I assume that still applies.

In order for a device to be used as a LINEAR amp I was taught that the device must be operated within the linear (straight line) part of the device's characteristic curve.  When the device is driven to the point where it is being operated out of the linear part of the curve, which is most often high plate or collector current, the device is no longer considered to be a LINEAR amp.  That is why when IN MY OPINION any 3-500Z is used in a LINEAR amp it should be operated within the linear portion of the curve.  In EIMAC tubes that used to be up to around 400 mA of plate current.  Driving an EIMAC 3-500Z so the plate current exceeds the linear portion of the curve results in an amp that is no longer linear.  Whether or not that causes problems or a "dirty" signal is an issue that I cannot address.

Dick  AD4U

I recommend either a commercial trapped dipole or a fan dipole.  If you use good quality coax, losses in 250 feet at the frequencies you want to use (160M-40M) should be low.

Dick  AD4U

"Eimac hasn't built a 3-500Z in decades.  The tubes used in the AL-80B aren't Eimacs, they're 3-500ZGs (graphite anode) built elsewhere.

Philips (now Richardson) specs the Amperex 3-500ZG quite differently.  If you refer to the Amperex data sheet, (lower section of page 3) they list OPERATING CONDITIONS as 3000Vdc Ep, and 770mA peak anode current, for 1420W peak output power (single tube): http://www.mhzelectronics.com/ebay/manuals/amperex_3-500z_tube_datasheet.pdf

I have no idea why people still refer to Eimac data sheets that are 40 years old, when Eimac doesn't manufacture this tube. "


On page 3 of the Amprex 3-500ZG tube data sheets that you linked us to, the maximum peak plate current of 770 mA is for a single tube in an AUDIO AMPLIFIER or a MODULATOR.  

If you refer to page 2 of the Amprex 3-500ZG tube data sheet and look under LINEAR AMPLIFIER service, the ABSOLUTE MAXIMUM plate current of the Amprex 3-500ZG tube in LINEAR AMPLIFIER service is 350 mA.

Dick  AD4U