[ARC5] The HP-606 saga. (Was screw removal, but now it's different ...)

[Leslie Smith]

Hi Wayne,
Thanks for the offer.
I have good news and bad news.
First - the good news.  I fabricated a tool made from a "proper" (short)
Allen wrench.  (We call them Allen keys, but down here, on the other
side of the world, we're funny ...)  So - that's the good news.
More good news.  Poked around and replaced the 250mA fuse.
Turned the set on for a few moments.  (I'll speed this story up a bit
....)

(Had been told "sig gen is working" by the knowledgeable fellow who sold
it to me.)
So I turned it on a few times and then off, each time giving it a longer
"on" spell.
Measured +300V line.  -3% from expected i.e. 289 volts.
Measured -200V line.  As expected.
Measured 25V heater line.  As expected.

Cycled power over several hours, first "on" 10 seconds, then off for
some minutes - I'm giving the caps time to "make".  Also pls note:  I
bought this from a fellow who knows a good deal more than I do, and he
said, "It's ok."  Got to the place where I left the 606B "on" for 5
minutes, then 10 etc.  Cleaned up a bit ... 

Let the 606 sit (power on) for about an hour - zero beat with a local AM
radio station.
Feeling happy.  Thinking coffee.  Don't mind the incessant rain outside.

Decided, "Right.  Time to look at the output waveform."
In terms of output - frequency = very close to spec.
In terms of output - amplitude is NOT to spec BUT I'm not terminating
into 50 ohms so ....

Found the output was consistent in terms of amplitude as I swung the
attenuator thru the range from "little" to quite "big".  Avoided the two
highest range.  (See manual, which suggests avoiding the 3V range except
where needed.)

Decided to measure the output at the low and top freq on every band.
Noted excellent correspondence between dial and observed freq. out.  
Repeat this at 50kHz ... 530kHz ... and "up".
Thinks to self, "Self, this is looking good."  Feeling happy.

Swung turret bandswitch "up" to (probably) second highest band.
Saw "Flash!"  Heard "Bang!"  Observed: white smoke.  
Noticed a peculiar but familiar stink.  
I noted it came from under a particular valve.
Thinks to self, "Self, I believe there is a relationship between flash,
band and stink."
I made the judgement:  "This is NOT as it should be ...."

I turned the set "off" and made a cup of coffee.
I thought a little and went to bed ...
Tomorrow is another day ...
Maybe I can calibrate my ARC-5 sets some other way ...

73

  Leslie Smith
  vk2bcu at operamail.com


On Fri, Mar 2, 2012, at 09:08 AM, Wayne Eleazer wrote:
> My HP-606A came with the Loooong Allen wrench.  It's not a Bristoll but
> an Allen.  I'll measure it when get the chance.
> 
> Wayne
> WB5WSV   
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