[Central-Electronics] 6550

[Jim Candela]

Gordon,

"At first I thought it might be the RFC-1,  mine shows 2.3uH when measured out of circuit"

  Looking at the schematic, RFC-1 says .022mh. This converted to uh is 22uh. I'd remove that part temporally and run up the drive. This might explain why you have more power output with increasing frequency. 

Jim
WD5JKO


________________________________
 From: Gordon <gordon at n6wk.com>
To: central-electronics at mailman.qth.net 
Sent: Wednesday, July 24, 2013 6:25 PM
Subject: Re: [Central-Electronics] 6550
 

Hi George and the Group,
George, I have double checked everything you mentioned..Same results.
  I tried the new tubes, and as everyone said,  They are NOT the problem.
I do have a question though. If I disconnect the Coax from the last 
wafer that goes to the RF Sampling circuit and the SO-239 connector, 
Connect my MFJ-259 to the loose end of the Coax  , with a 50 Ohm load in 
the SO-239, shouldn't the MFJ-259 show 50 ohms? Mine is no where near 50 
ohms. If I check the dummy load by itself, it is exactly 50 ohms.
The only thing on that Coax is the Amps Sampler for the RF output and 
the SO-239. At first I thought it might be the RFC-1,  mine shows 2.3uH 
when measured out of circuit, So it appears to be good.
I also noticed that the Neutralizing Cap is NOT shown on the 100V 
Schematic I have in front of me.

Gordon
N6WK



On 7/24/2013 9:48 AM, George Maier wrote:
> Hi Gordon:
>
> Great job on the 100V; glad to see so much enthusiasm for such a worthwhile
> project.   Not sure why you are having the RF O/P problems, but your coupler
> sequence is correct, and the voltages all seem within limits.  Not sure what
> you've done electrically, but here are a few simple things you may want to
> consider, if you have not already addressed them.  If you have, please
> ignore my drivel:
>
> 1 - Remove each coupler and apply a high quality contact cleaner to the base
> pins and the tap connectors; i.e. - Caig Pro-Gol applied with a q-tip or
> Caig pen.
> 2 - Same exercise for all of the of the lower stage coil banks, which are
> all removable.
> 3 - Be sure to replace the 100 mf - 15V cap (C418) across the PA screen over
> current relay; they're almost always bad. Also, burnish the relay contacts.
> 4 - Check the 10 Ohm resistor (R450) that is in series with the power
> control,  to make sure it's not open., and also the rest of the surrounding
> connections and circuitry.
> 5 - Remove all of the chassis interconnecting plugs (carefully) and clean
> them with Pro-gold also.
>
> Those steps should help to eliminate any flaky stuff, unless of course you
> do have bad tubes along the line.  Generally, I agree with the other folks
> here, that the PA tubes do not usually fail totally, but hey, it's certainly
> possible.
>
> Keep chugging, Gordon; you'll get there!
>
> 73, George - W1LSB
>
>
> -----Original Message-----
> From: central-electronics-bounces at mailman.qth.net
> [mailto:central-electronics-bounces at mailman.qth.net] On Behalf Of Gordon
> Sent: Tuesday, July 23, 2013 9:02 PM
> To: central-electronics at mailman.qth.net
> Subject: Re: [Central-Electronics] 6550
>
> I am still fighting the no to Low output on my CE-100V.
> I have ordered new 6550 tubes, but now I am thinking they are nt the
> problem. The tube tester shows both as very strong I am now wondering if
> someone has mixed up the Broadband output Coils.
> Can anyone tell me what color is correct for each band?
> I have Red for 80, yellow for 40, green for 20, blue for 15 and slate for 10
>
> Is this correct?
> I have now discovered that I get more output as I move up in bands. I get a
> whole 12 watts out on 20 and 15 meters..LOL Is there a way to test the
> center Frequency of each of these broadband output coils?
>
> Thanks,
> Gordon
> N6WK
>
>
>
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