Heathkit HP 23 Fixed Bias Voltage

[Bernie Murphy]

That should be OK.  Since the bias supply is under load, the value looks 
reasonable.

I assume that you can set the idle current on the finals at 50 mils? If so, 
you should be good to go.

Also, check the voltage on the +HV when transmitting to make sure the power 
supply is not sagging under load (usually caused by bad electrolytics). Will 
drop to around +790V or so on CW key down.

73, Bernie


----- Original Message ----- 
From: "Tom Buchanan" <tlbuch at SCRTC.COM>
To: <HEATH at LISTSERV.TEMPE.GOV>
Sent: Sunday, February 18, 2007 1:57 PM
Subject: [HEATH-TEMPE] Heathkit HP 23 Fixed Bias Voltage


>I am working on a HP 23 power supply.  I found a bad capacitor (40MFD/450V)
> and replaced it with a modern electrolytic of same value.  All other parts
> appear to be original.  The following voltage readings were taken with a
> Heathkit SB101 on receive:
>
>
>
> * +LV = 318v - 323v
> * +HV = 823v
> * -130v Fixed Bias = -112v
> * Adj. Bias = - 58v
>
>
>
> Is the Fixed Bias voltage in an acceptable range or should it be closer to
> -130v?
>
>
>
> Thanks,
>
>
>
> Tom KG4KGY
>
>
>
>
>
>
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