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Re: [Amps] SB220 Meter blown

Subject: Re: [Amps] SB220 Meter blown
From: Artek Manuals <>
Date: Fri, 15 May 2020 13:14:26 -0400
List-post: <>
Comments below

On 5/15/2020 12:13 PM, Jim Thomson wrote:
Date: Fri, 15 May 2020 11:10:06 -0400
From: Artek Manuals <>
To: "" <>
Subject: [Amps] SB220 Meter blown

<I am resurrecting a SB220 that had an apparent classic Grid/plate short
<event. One of casualties appears to be the right hand meter movement.
<This is the one for Grid Current and HV. I am pretty far into it and the
<meter movement measures open , the internal shunt resistor is blackened
<( and open?)

<Anyone got a surplus movement from a parted out unit? Nothing found on
<evil-bay at the moment

<Dave NR1DX

## I believe harbach sells replacements. The heathkit shop might sell em.

They only have "meter diode/ resistor boards" no actual meter movements

The rest below are all good ideas but moot if I cant find a meter movement, Nothing in my manual says what the actual values of the movement is either 8^(

Next time be sure to install rvs connected 6A10s or 1N5408s between
B- of hv power supply caps..... and chassis. HV fuse, followed by 50 ohm glitch resistor is series
with B+.

## Toss all the grid chokes and caps. Bond each of the 3 x grid pins directly to chassis
with strap.

## Install a 2nd HV series with one leg of the plate xfmr secondary....either leg.

## Ok, now there is no way to blow anything up..including meters. Cro bar anything u want,nothing happens
except for a blown hv fuse.


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