[Amps] Equalising the air flow on Commander 2500 tubes/replacement neoprene chimneys

[Carl]

Is that a Command built or Palstar built amp? A very visible Palstar change 
is the air holes added to the front face of  the RF chassis to cool the PS 
board which was easily fried and a royal PITA to access..

Palstar made many changes to the RF deck but what you describe is one I have 
not seen in the many amps Ive serviced....especially the no chimneys 
version. That sounds more like a Hammy Hambone job.

Carl


----- Original Message ----- 
From: "Jay Sturtevant" <k2ztdx at gmail.com>
To: "Steve Ireland" <vk6vz at arach.net.au>
Cc: <amps at contesting.com>; "Phil Hartwell" <vk6gx at yahoo.com>
Sent: Friday, July 27, 2018 11:30 AM
Subject: Re: [Amps] Equalising the air flow on Commander 2500 
tubes/replacement neoprene chimneys


> Steve,
>
> I have a Commander HF 2500, 1996 vintage, however, there are no chimneys 
> on
> top of the 3cx800s and I do not have a "solid screen".
>
> The amplifier you're describing may be a later vintage.
>
> I don't want to waste your time-- curious.
>
> Thanks!
>
> Jay, K2ZT
>
> On Fri, Jul 27, 2018, 10:13 AM Steve Ireland <vk6vz at arach.net.au> wrote:
>
>> G’day everyone
>>
>> A good friend of mine has recently acquired a Commander 2500 which is 
>> need
>> of repair/rebuild after a long and hard life.
>>
>> On taking the amp apart, he noticed one of the neoprene chimneys on the
>> (two) 3CX800 tubes was more melted than the other.  He then put the amp’s
>> fan on and discovered the tube with the more melted chimney was receiving
>> considerably less air flow than the other, owing to a screen placed 
>> between
>> the two tubes.
>>
>> A potential solution was to replace the solid screen with a mesh one, but
>> I said it was likely that someone on this reflector had already come up
>> with a solution/modification to solve this problem and I’d ask for him.
>>
>> It also occurred to me that someone may know where some suitable neoprene
>> can be purchased, so he can make replacement chimneys for the two tubes.
>> Any ideas on this would also be approached.
>>
>> Vy 73
>>
>> Steve, VK6VZ
>>
>> ---
>> This email has been checked for viruses by Avast antivirus software.
>> https://www.avast.com/antivirus
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
> 


---
This email has been checked for viruses by AVG.
https://www.avg.com