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yamanx1 Profile
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Head Honcho

Registered: 09-2007
Location: In a world of my own
Posts: 4777
Karma: 25 (+26/-1)
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L4 PS Harbach conversion


Well about a year or so ago my L4B Drake Linear amplifier went kaboom! It kind of is the reason I haven't been as active as I would normally be. I just turned it all off, turned out the lights and got on with other things.

Gutted.

Then I thought, lets have a go at getting it fixed. Well I contacted everyone I could find on the internet to help me. No-one.

So lets get it on the bench and have a look, now this is dangerous stuff, very high voltages, and it really is best to know what you are doing. My knowledge is even more dangerous, because I have some, but not really enough.

Never-the-less, I have a good look to at least see if I could "see" the problem. I thought I could, I replaced the 50k ohm resistors and the .82 safety one which was clearly damaged.

It never came on, each time I switch the power supply on the 13amp fuse went within a millisecond. Doh!

Put it away then.

So I've got an expensive non-working linear. Not acceptable, there must be a way and information out there to carryout repairs. I hit the internet in earnest.

I bought a Harbach power supply kit from the USA, set myself up on the bench, built it, fitted it, checked it.

It worked, I now have a fully functioning Drake L4B linear amplifier, good for around 1500 watts emoticon

It has taken me quite a while to, get myself properly organised, get the parts and get around to doing the job.

I have made a neat and tidy job as well emoticon



---

By all means think yourself big, but never think others small.... R.F.Scott
10/Sep/2019, 4:50 pm Link to this post Send Email to yamanx1   Send PM to yamanx1
 
Vendee85 Profile
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Freebander

Registered: 08-2016
Location: Yeovil
Posts: 13
Karma: 0 (+0/-0)
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Re: L4 PS Harbach conversion


Hi Dave.

 Congrats on sorting ur ps. I too have handled
 High Volts on Radio's/TV's ie. CRT tubes in
 '50/60s. Why do U need 1500w? Are u trying to
 Contact Aliens on Exoplanets 110 mil light
  yrs away. I've never used more than 100w in
 60yrs of operating radio's Qrp is fun & a
 Challenge. 73's Mike 855.
14/Sep/2019, 11:37 am Link to this post Send Email to Vendee85   Send PM to Vendee85 Blog
 
yamanx1 Profile
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Head Honcho

Registered: 09-2007
Location: In a world of my own
Posts: 4777
Karma: 25 (+26/-1)
Reply | Quote
Re: L4 PS Harbach conversion


1500w is way too much, but its like having an R1 on the road emoticon

---

By all means think yourself big, but never think others small.... R.F.Scott
14/Sep/2019, 1:57 pm Link to this post Send Email to yamanx1   Send PM to yamanx1
 


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