• You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.

Toshiba 2290 testing info.

Up to 45 bucks as of today at RF Parts. Makes it sound as if stock is dwindling.

73
No matter how hard one tries, you'll never be able to pay more money for any RF part, than when you buy it from RF Parts. This is the same company that raised the price on the 2879 from $14.99 to $204.99 over the last 25 years. Also, the $44.95 for this transistor at RF Parts, has not changed since I first found it there over a year ago. Not to mention, every other source I can find for this part, has it for less than half the price as RF Parts.

I'll also mention the complete inability to purchase a single quality glass tube anywhere today, has this company in an awkward position of having to be resistant when covering tube warrantees, in an effort to reduce their losses with respect to the flood of crappy tubes on the market today. If Merritt's wife tries to stick you with filling out a complete tube failure form before taking back their junk, just do what we do. How many people have their eyes glued to the grid current meter at the second the tube fails?

RF Parts knows the tubes sold today have far from a hard vacuum inside and yet they now want you to jump through hoops to facilitate a return on this glass junk. If they try to beat you like this, just go to the tube data sheet and give them any of the normal numbers they want, from the class of operation in use. The only way to force a normal grade of tube quality back into production, is to consistently reject all of the garbage that didn't get pumped down to a good vacuum level and won't provide a fraction of the life as a result. Trying to get away with selling every marginal tube you can, is counterproductive.

25 years ago RF Parts had a responsive employee named Chip that handled defective parts shipped to customers like a dream. One day I called and got my first different experience from them and found out they fired Chip. When I asked why, I was told "He didn't have the companies best interests in mind"! 25 years later and the owner still hasn't figured out that addressing customers concerns regarding defective parts, was absolutely placing the companies long term interests FIRST!
 
Last edited:
I am still working on this.. here are several pics. I did find out that the burnt resistor is 10 ohm and the bias choke 2.2 or 2.7
 

Attachments

  • 20210502_071037.jpg
    20210502_071037.jpg
    3.2 MB · Views: 106
  • 20210502_071054.jpg
    20210502_071054.jpg
    1.3 MB · Views: 112
  • 20210502_071109.jpg
    20210502_071109.jpg
    3.6 MB · Views: 109
  • 20210502_071118.jpg
    20210502_071118.jpg
    3.8 MB · Views: 109
  • 20210502_071144.jpg
    20210502_071144.jpg
    1.5 MB · Views: 106
  • 20210502_071156.jpg
    20210502_071156.jpg
    1.5 MB · Views: 95
  • 20210502_071209.jpg
    20210502_071209.jpg
    3.1 MB · Views: 101
  • 20210502_071223.jpg
    20210502_071223.jpg
    3.6 MB · Views: 99
  • 20210502_071230.jpg
    20210502_071230.jpg
    3.4 MB · Views: 119
  • 20210502_090716.jpg
    20210502_090716.jpg
    1.3 MB · Views: 111
Update..

So what I have done is replaced all the bad value parts as I pulled them out and tested 1 at a time. The 2290 & 2789 are all good with forward induction. At this time it was still not working correctly, it would pass thru signal fine and the SWR staying the same. When I would key up they relay would activate and the corresponding led would light as well but immediately the SWR would shoot up and no output. I decided to clean the relay and then it started working, Yay. I tested the unit and about 15 minutes later it was down again. I did notice that the relay was arching inside sometimes as I was keying up. They relay sticking open and the receive not activating. I am going to take out the relay and hopefully I can still read the case and order a new one.

So here would be the setup if anyone could help me with what I should actually see out of the amp or explain to me how to get the approx value's myself if Im not doing it correctly.

Icom 7300 - output on 28.410 AM
4 watts into the 2290
Stacked power supplies at 13.8v (80amp) available.

If I am reading the spec sheet correct for the 2290 at 12.5v 2.5-4w 60wPEP so this would average 24-30w. If we split that into 4-2879 that would be 6w into each. Spec sheet on the 2879 at 12.5v 6-10w 100wPEP. So 4x100=400wPEP about 150-200w average.

I was watching a video on the same amplifier he had this setup..
15v power
30w radio
claiming 800-900w pep

Any help clarifying would be appreciated.
 

dxChat
Help Users
  • No one is chatting at the moment.
  • @ Wildcat27:
    Hello I have a old school 2950 receives great on all modes and transmits great on AM but no transmit on SSB. Does anyone have any idea?
  • @ ButtFuzz:
    Good evening from Sunny Salem! What’s shaking?
  • dxBot:
    63Sprint has left the room.