[NJARC] Radio Debugging PS

[Al Klase]

Hi Scott,

Why didn't you replace the main filter caps when you're agonizing over 
all the minor details?  They're 70 years old, and are the ones that are 
going to kill your power transformer when they short out.  Leave them in 
place.  Cut them dead, and install some new caps below decks.

While it's a good idea to make sure each tube has reasonable plate and 
screen voltages, it's a fool's errand to carefully measure all the 
voltages, and attempt to access the condition of the set from the 
resulting matrix.  What works?  What doesn't?  Which stage is questionable?

1.  Signal trace to the BAD STAGE.
2.  Make voltage measurements in that stage to identify the BAD 
CIRCUIT.  (Plate, screen, grid, etc.)
3.  Turn off the power, and make resistance measurements to find the BAD 
COMPONENT.

(Testing the tubes is a good idea as well.)

Clear the first problem and move on to the next one,

Have fun,
Al

Scott Roberts wrote:
> Visit our web site - See http://www.njarc.org
> _______________________________________________
> PS- I replaced all the paper caps, and a coupe electrolytics, but
> NOT the two large electrolytic caps C-44 & C-45, both 16mfd @
> 400V. I replaced electrolytic cap C-40, 10mfd @ 25v, with a 10mfd
> 450. Is this too big? or just overkill?
>
> Scott
>
> --- Scott Roberts <ng19delta at yahoo.com> wrote:
>
>   
>> Visit our web site - See http://www.njarc.org
>> _______________________________________________
>> Hi Everyone!
>> I am finishing up my recap on the Hallicrafters SX-16. Today, I
>> checked the voltages on the tubes, using an  Extech True RMS
>> DMM,
>> Model 22-816. I am working with about 113VAC house current. 10%
>> tolerances, per manual. Settings IAW Hallicrafters manual
>>     
>
>
>
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-- 
Al Klase - N3FRQ 
Flemington, NJ 
http://www.skywaves.ar88.net/