[Collins] 30L-1 Problem

[Dr. Gerald N. Johnson]

On Sun, 2006-06-25 at 14:43 -0500, Robert & Linda McGraw K4TAX wrote:
> At present my 30L-1 is being operated from a 120 volt mains.  Actually 
> measures about 126 VAC no load.  I'll switch it over to the 230 volt 
> configuration when I replace the 6 filter caps and perform a diode check.
> 
> Plate voltage (no load) is 1950 volts
> Plate voltage (full load) is 1600
> Plate current is 0.650 A
> DC input power is 1040 watts
> Output is 700 watts
> Efficiency is 700/1040 or 67.3%
> 
> I suspect the 811A's are getting a bit soft in your case.  Every thing else 
> seems about normal even though the voltages are a wee bit high.  The book 
> says 230 VAC +/- 10%.  Remember this is a voltage doubler type power supply 
> so a 5% increase on the primary would net about 10% on the secondary which 
> is about what you are seeing.

NOPE! 5% is 5%. 5 volts change at the transformer gets 14 volts at the
DC point but its still a 5% change.
> 
> As to the voltages on my amp, I measured these using the front panel meter 
> after confirming its accuracy at 1000 volts with the unit being powered via 
> a Variac.  I was in the process of "bringing it up" after it being stored 
> for 20+ years.  My DVM only measures to 1000 volts.  It still has the 
> original filter caps and diodes.  However, new caps are on order.
> 
> 73
> Bob, K4TAX


-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer