[Amps] AL-82 "Glitch" Protection

[Punkymcd at pacbell.net]

I understand the meter protection scheme but if you take the time to read the 
AL-82 schematic provided with the amplifier you will see on page 13 the 
capacitor board is listed as 50-01167-1 and on page 13 the same board is listed 
as 50-01143-1. On the latter there is tie point named PCM. Maybe (P)late 
(C)urrent (M)eter but it's unclear what point it is attached to the metering 
board. Point to point check of wiring on the amp has it connected to the B- side 
of R1 and R2.

Back to drawing.....

Don, W6OA

R. Measures wrote:
> **  The easy solution is to protect the meter movements with back to back 
> 3a diodes across the movements themselves.  Protecting the shunts 
> requires some knowledge of polarity at the shunt, understanding that Si 
> diodes Begin to conduct c. 0.5V,  as well as knowing basic Ohm's-Law.  
> 
> 
>>Comparing grid and plate current metering circuits of the SB-220 and AL-82 I 
>>find the AL-82 grounds the negative side of the plate meter. Trying to 
>>sort out 
>>how to install the metering glitch diodes is a bit confusing here. Of course 
>>Ameritron's idea of an amplifier schematic doesn't make things any easier to 
>>trouble shoot.
>>
>>Can anyone give me some help as to where to physically (electrically that 
>>is) 
>>put these diodes. I can understand the one across the grid current shunt 
>>resistor but I need help with the three in series from -HV to ground.
>>
>>Is there by chance a schematic of the AL-82 that incorporates all the sub 
>>boards 
>>in one print?
>>
>>Thanks in advance.
>>
>>73, Don, W6OA
>>
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> 
>