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yamanx1 Profile
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Heathkit SB221


#@*$£!?~+&*!

 emoticon

I'll tak about it later emoticon

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By all means think yourself big, but never think others small.... R.F.Scott
3/Mar/2011, 8:08 pm Link to this post Send Email to yamanx1   Send PM to yamanx1
 
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posticon Re: Heathkit SB221


"Live its too short for QRO" emoticon

Good luck and BE AWARE of HIGH VOLTS with lamps... 73 de Juan
3/Mar/2011, 10:43 pm Link to this post Send Email to 30fb001   Send PM to 30fb001
 
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Re: Heathkit SB221


Its fixable Dave, dont go swinging the lump hammer yet.


Mark

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http://gw0wvl.weebly.com/
5/Mar/2011, 12:37 am Link to this post Send Email to madmark1   Send PM to madmark1 Blog
 
yamanx1 Profile
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Re: Heathkit SB221


OK, having now spent the best part of 30 hours on it, I think I know what the problem is. The capcitors for the HV and the resistors require replacing.

I haven't decided yet whether to fix it or return it, but it is a good example apart from the fact it dont work!

Apart from the time, its cost me a sixty five quid multimeter, binned it as it was toast and the TS 870 wont TX now from 40m emoticon this is the band I was testing the amp with, low power, but who knows, I'll sort that later.

I have decided this baby is my nemesis emoticon

It may have to go.

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By all means think yourself big, but never think others small.... R.F.Scott
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Re: Heathkit SB221


Thank God its not just me that can bugger radios [sign in to see URL]


Good luck with it..


VC7 Jon
5/Mar/2011, 8:41 pm Link to this post Send Email to VC7   Send PM to VC7
 
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Re: Heathkit SB221


i`m just gratefull that the meters lead insulation was up to snuf, and that we`re not mourning your a$$ and looking for a new Admin!

Praise the Lord for small mercies! 65 quid is nothing compared to other outcomes emoticon

BTW, I repair/restore old valve radios, so if you Need anything, I`ll have a look and see if I can help, I also have several Online resources to get the old HT caps and a few tricks to Gut the old ones and replace with Modern ones but keep the original "Look".
I`m sure Others here are similarly equipped and will help too emoticon

---
I`m also on Twitter as "YT2095" ;)
6/Mar/2011, 12:02 pm Link to this post Send Email to YT2095   Send PM to YT2095 Blog
 
yamanx1 Profile
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Re: Heathkit SB221


Right then, I've kept it emoticon Done a deal with the seller, the valves are good (I think) and the trannies are good as well, so as Mark says, the rest is a project emoticon

What difference would I find from 8 off 450v caps instead of 500v?

---

By all means think yourself big, but never think others small.... R.F.Scott
25/Mar/2011, 7:10 pm Link to this post Send Email to yamanx1   Send PM to yamanx1
 
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Re: Heathkit SB221


Try these guys, I know a few that have and they come with a good rating, hopefully this will help you also, and Happily they now have an English translation there too emoticon

[sign in to see URL]


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I`m also on Twitter as "YT2095" ;)
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Re: Heathkit SB221


quote:

yamanx1 wrote:

What difference would I find from 8 off 450v caps instead of 500v?



It would make a loud bang, that's all. emoticon

Seriously though, it would be worth fitting 9 in place of the 8, including the extra bleeder resistor.

Increase the capacitance of all 9 to allow for the drop in the combined capacitance - you know how to work that out, don't you?? emoticon

Actually, I doubt you'd notice any real difference if you were to use caps of the same capacity. If you are brave, measure the HT and see if you really need 500v caps X 8. Maybe 450v ones would do, but if it were me doing this, I wouldn't want to see any more than 400v across each cap off-load, just to be safe.

What's wrong with the original caps?



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yamanx1 Profile
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Re: Heathkit SB221


Maybe nothing wrong with the original caps, I'm just surmising, as there is no HV on the meter. As far as I can tell, there is no faults with the meter circuit, there is HV at the anodes emoticon trust me there is emoticon but I dont know what it measures.

I know the valves are good because I've tried a good one and no difference, I'm half certain T1 and T2 (ransformers) are good because of the hi voltage at the anodes. But the caps have some evidence of big heat, the holders have melted, and they're original items, probably 40 years old or more.

I dont have all the necssary test equipment here, but I'm ebaying atm emoticon Also John FB193 has offered to loan me some test kit which will help me work through the problem. Methodically, after all PA's are nnot rocket science, are they? (Actually maybe they are emoticon )

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By all means think yourself big, but never think others small.... R.F.Scott
27/Mar/2011, 3:52 pm Link to this post Send Email to yamanx1   Send PM to yamanx1
 


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