[Heathkit] meter basic movement in SB 220

[Mark K3MSB]

John –



I have successfully used a meter from an HM-2102  to replace a blown out
SB-220 meter.



I believe BOTH the SB-200 and SB-220 amps use the same 200 uA meter.



I believe that SOME of the HM-102 or 2102 meters can be directly used, but
you have to check first.



I made measurements on an SB-220 meter and came up with the following:



280 mV for full scale deflection

1400 ohms measured resistance.



Full scale deflection current = 0.28 / 1400 = 200 uA



The meter from an HM-2102 was DIFFERENT:



105 mV full scale deflection

1040 ohms measured  resistance



Full scale deflection 0.105 / 1040 = 100 uA



My notes show that I put a 1760 ohm resistor in series with the HM-2102
meter, and shunted the pair with 2800 ohms.



I hope this helps.



73 Mark K3MSB


On Mon, Jun 9, 2014 at 2:54 PM, John King via Heathkit <
heathkit at mailman.qth.net> wrote:

> In the back of my feeble mind, I seem to remember that the movement in the
> HM102 watt meter is the same as the plate
> current meter in the SB 220 and the HM 102 meter can b used in the SB 220
> with a swap of meter faces from the the HW 102 to the meter in  the SB 220
> or Vice vesa. Please tell me what you know about the interchangeability of
> the Hm 102 movement with the plate current meter in the SB 220. Your input
> will be greatly appreciated. 73, John, K5PGW
> ______________________________________________________________
> Heathkit mailing list
> Home: http://mailman.qth.net/mailman/listinfo/heathkit
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Heathkit at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>