[Amps] AL-1200 Glitch Resistor

[Carl]

----- Original Message ----- 
From: "Paul Christensen" <w9ac at arrl.net>
To: <amps at contesting.com>
Sent: Sunday, April 12, 2015 9:10 AM
Subject: Re: [Amps] AL-1200 Glitch Resistor


> Carl,
>
> Any idea when it went into production?   I see it in the on-line parts 
> list as P/N 10-10154 for $19.11 but I don’t see it on the current PDF 
> schematic.

** No I dont Paul, time flies at my age but Id say at least 5-6 years.


> In this particular AL-1200, the only HV fault current limit is though the 
> filament choke, plate choke, PCB traces, and wiring post HV filter cap 
> board.


** As its been since the 80's when it came out.


> A single 1N5408 does exist between B- and chassis ground.

** Thats an upgrade as it used to be a 1N4007 which was considered 
sufficient by its "designer" but the slightest little burp would short it.

 Their schematics need a thorough clean-up.  I noticed several parts,
> off-sheet connect points, and module numbers that don't match-up.  Some of 
> this may be due to evolutionary changes.

** Good luck with that, their latest schematics are harder to read than ever 
so it takes longer to find errors which werent changed.
Pretty soon they will equal TenTec for schematic confusion.

Carl
KM1H


>
> Paul, W9AC
>
> -----Original Message----- 
> From: Carl
> Sent: Sunday, April 12, 2015 8:45 AM
> To: Paul Christensen ; amps at contesting.com
> Subject: Re: [Amps] AL-1200 Glitch Resistor
>
> See the photos of the current big Ameritron series. They use a big carbon
> resistor that is in the parts list, sort of pricey however.
>
> Carl
> KM1H
>
>
>
> ----- Original Message ----- 
> From: "Paul Christensen" <w9ac at arrl.net>
> To: <amps at contesting.com>
> Sent: Sunday, April 12, 2015 8:25 AM
> Subject: [Amps] AL-1200 Glitch Resistor
>
>
>> I'm working on an AL-1200 for a friend.  While finding the problem in the 
>> PS, I noticed that a glitch resistor is absent in the design that would 
>> otherwise limit HV fault current.  I verified this on both the schematic 
>> and by tracing actual amp wiring.  I was expecting a resistor (e.g., 
>> 50/50W) in the B- lead, or in the alternative, in the B+ lead with 
>> appropriate isolation.  While the 3CX1200 may be statistically immune to 
>> flashover, it seems a good idea to include one to ensure that HV fault 
>> current is limited under all conditions.
>>
>> Has anyone here added one to their AL-1200?
>>
>> Paul, W9AC
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