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Re: [Amps] Upgrades for LK500ZC?

To: "Zev Darack" <zevdarack@gmail.com>, "amps" <amps@contesting.com>
Subject: Re: [Amps] Upgrades for LK500ZC?
From: "Carl" <km1h@jeremy.mv.com>
Date: Fri, 20 Jul 2012 19:08:16 -0400
List-post: <amps@contesting.com">mailto:amps@contesting.com>
I believe the Ameritron are higher value and a higher rated peak, they are 
also all tested for leakage and voltage at incoming inspection.
There is no need to spend extra on the JI "inspired" pulse rated resistors, 
no other manufacturer does.

Ameritron usually sends what you ordered if you give them the correct part 
number or description; I spend a few thousand dollars a year with them and 
havent had a problem yet.

Carl
KM1H


----- Original Message ----- 
From: "Zev Darack" <zevdarack@gmail.com>
To: "Carl" <km1h@jeremy.mv.com>; "amps" <amps@contesting.com>
Sent: Friday, July 20, 2012 11:48 AM
Subject: Re: [Amps] Upgrades for LK500ZC?


> Carl,
>
> I appreciate your response.  I could not find suitable 450v screw down
> capacitors for less money than Harbach charges (including shipping).
> I know you can get snap in caps for cheap but is it possible to solder
> the snap in caps into the holes for screw down caps?  If it is I may
> go that route for my SB220.
>
> In looking for an appropriate glitch resistors I found info
> recommending the RCD Pulse rated resistors in a article from
> NE7X/W8JI: http://ne7x.com/Henry_B_minus_resistor.htm
> turns out that Ameritron just sent me the wrong part (non pulse rated)
> so I can't use what they sent me anyway....Ameritron quality control
> hihi
>
> In the wirewound I see OHMITE L25J25R 25 OHM 25W around for <$10.
> Anything else you would recommend?
>
> I was thinking of mounting it right on the side of the Power supply
> board B+ output.  Is there any reason to put it inside the RF section?
> I would think that you would want to avoid that?
>
> 73,
> Zev N2WKS
>
> On Thu, Jul 19, 2012 at 12:02 PM, Carl <km1h@jeremy.mv.com> wrote:
>>
>> ----- Original Message ----- From: "Zev Darack" <zevdarack@gmail.com>
>> To: <amps@contesting.com>
>> Sent: Tuesday, July 17, 2012 2:10 PM
>> Subject: [Amps] Upgrades for LK500ZC?
>>
>>
>>
>>> I am in the process of upgrading an LK500ZC and am looking for
>>> recommendations:
>>>
>>> I am currently working on the following:
>>> 1. Installing the Harbach Power Supply
>>
>>
>> I see absolutely no reason to waste money on that, just buy new caps from
>> Ameritron
>>
>>
>>
>>> 2. Installing the Harbach Soft Start
>>
>>
>> Most ZC's came with it but none of the earlier models had a problem
>> withoutit....its just a useless frill in that amp that can cause its own
>> problems.
>>
>>
>>> 3. Replacing the Plate Choke which was rewound by someone with an
>>> Ameritron Plate choke.
>>
>>
>> They work well
>>
>>
>>
>>>
>>> The amp also has a fuse between the Zener diode and the QSK board so I
>>> am going to install a panel mount fuse holder for this.
>>
>>
>> If the fuse blows you better go inside and find out why instead of 
>> drilling
>> holes.
>>
>>
>>
>>> KM1H recommended I install Glitch protection.
>>
>>
>> Yep
>>
>>
>>
>>> The current tubes are showing a blue color during transmit so I will
>>> be replacing the tubes as well.  Eventually one of the tubes flashes
>>> over and causes the fuse on the zener diode to blow.  The amp is
>>> putting out over a KW so I think everything else is ok.
>>>
>>> Questions:
>>> 1. Glitch protection: I plan to add 3 10 ohm RCD 175P-10R0-FBW
>>> resistors in series in the B+ line.
>>
>>
>> Whatever they are?
>> Why not just one 20 Ohm 25W enamel wirewound?
>>
>>
>>
>> Looking for advice on where/how
>>>
>>> to mount this in the amp?
>>
>>
>> Replace the small RFC at the base of the plate choke with the resistor.
>>
>>
>>
>>> 2. Recommended mounting location for the soft start in the amp?
>>
>>
>>
>> The factory one mounted above the power distribution board
>>
>>
>>
>>> 3. Is there anything else I should look at that could have caused the
>>> tubes to go bad?
>>
>>
>>
>> Lack of use and regular gettering
>>
>>
>>
>>> 4. Are there any other recommended upgrades for this amp?
>>
>>
>>
>> The Ameritron choke will improve 160M output. Id measure the parasitic
>> resistors and if out of spec replace with Ohmite OY type from Mouser.
>> At the front wafer, right side support make sure there are no sharp edges 
>> on
>> the 160M lug. Also paint the junction of the ceramic spacer, nylon 
>> washer,
>> and wafer with an anti corona dope or something else to prevent an arc to
>> that 160M contact.
>>
>> Carl
>> KM1H
>>
>>
>>
>>>
>>> Thanks es 73,
>>> Zev N2WKS
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>>
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>>>
>>
>
>
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