The PM 800 caps are superior and modern technology. The other set goes back
to 1970's designs and once called computer grade.
If you look at the MFJ catalog they are selling 270uF screw terminal caps in
under half the height which are what is used in all their amps and the cap
internals are a modern design for those still using screw terminals.
Carl
KM1H
.
----- Original Message -----
From: "KB8NTY" <kb8nty@wowway.com>
To: <amps@contesting.com>
Sent: Tuesday, July 08, 2014 2:24 PM
Subject: [Amps] Amp Supply LK-500ZBx or generic P/S capacitor Question
Appreciate all the help this group provides.
I have a nice clean unmodified LK-500ZBx (not sure what the x means), an
early
serial number 500x, the all gray front not the colorful
version.
P.Dahl transformers, QSK option, no ALO, step start, or fan speed option.
Original 8438 code Eimacs, producing 1400 out on best band.
As an admitted somewhat novice in the amp theory I look to the group for
valued help
/ advice.
H/V seems to read 2900 +/- Idle, 2500 key down, but more concerning is
the
steady "buzzing"
coming from the P/S board (not the transformers) when powered on and when
keying
amp as well.
In the thoughts to save a impeding disaster a P/S replacement is in order.
I am a recovering leukemia patent, disabled, and recovering from both L&R
shoulder reconstructive surgeries from a fall after being discharged home
from long hospital stay.
Not complaining, I am blessed to be here and appreciate every day!
So not being up to repair/replace the original board, or ship out for
upgrade, I plan to purchase the PM-800 P/S from Harbach:
http://harbachelectronics.com/shop/amp-supply/pm-800-replacement-power-supply-module/
My question..I also see he offers a capacitor:
http://harbachelectronics.com/shop/misc/cp-210-set-of-eight-8-220-%ce%bcf-450vdc-filter-capacitors-with-sems-screws/
Similar to the original's in my LK-500ZB, these are physically larger than
the modern caps supplied with the PM-800 kit.
Any thoughts or opinions regarding the newer smaller modern caps compared
to
the older larger caps?
His smaller caps are 105 deg hi-temp rated, which is good. So considering
with
the values being close to the same 210/220 mfd, any reason to not go with
the smaller modern size?
Of-course the PM-800 board will be much easier for me to deal with and all
components & new board are all supplied, based on vintage the complete P/S
component replacement should be a good thing!...However if there is
compromise by use of the smaller size caps compared to the original larger
types, I will have to step back and re-evaluate my purchase plan.
I'm overthinking but if the smaller size, modern caps are equal or better,
has me overthinking then why dont present day tube amps such as ameritron
use the smaller caps?
Thank you very much for your thoughts and experience. I value your
contribution.
-73- Ross KB8NTY
RossRadio: RF Ground Radial Website
http://www.rossradio.net/
Ground Radial Discussion: Please Visit & Join In!
https://groups.yahoo.com/neo/groups/groundradial/conversations/messages
--------------------------------------------------------------------------------
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
--------------------------------------------------------------------------------
-----
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2014.0.4716 / Virus Database: 3986/7818 - Release Date: 07/08/14
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|