[Heathkit] Power supply parts for SB-200

[km1h]

That would certainly not be my choice of capacitor for a HV doubler supply. 
First of all the ripple spec is far from good, the load life is low and the 
temperature rating is only 85C. Now for many hams the mantra is "Cheap Is 
Best" but this is not the time to count pennies.

However I suggest the 105C Cornell Dublier 381LX series which is designed 
for switching supplies and is a superb cap for amp use. Ive been using that 
series since they came out for all my amp needs.

The Mouser # is 5985-450V150 @ $6.80 each in small quantities. Then reduce 
the heat in the PS compartment by replacing the equalizer resistors with 
100K 5W MOX. Mouser # 286-100K @ .49 each.

The 330MF version of that cap fits perfectly in the SB220 plastic blocks and 
noticably improves the regulation.

The amp you save may be your own.

Carl
KM1H
National Radio 1963-69
Member of NCL-2000 Design Team




----- Original Message ----- 
From: "Glen Zook" <gzook at yahoo.com>
To: <heathkit at mailman.qth.net>
Sent: Monday, November 21, 2005 11:44 AM
Subject: [Heathkit] Power supply parts for SB-200


> Since I have had several requests for the Mouser part
> numbers for the electrolytic capacitors and diodes to
> rebuild the power supply in the SB-200 linear
> amplifier it is easier just to post the information to
> the entire reflector.
>
> Also, the same capacitors are used in the SB-400,
> SB-401, HP-23 series, Apache, DX-100, Seneca,
> Marauder, and probably several other transmitters and
> power supplies.
>
> The original value is 125 mfd @ 450 volts.  The "new"
> capacitors are 120 mfd @ 450 volts.  Remember that the
> original capacitors had a tolerance of -50% / +80%
> while the new ones have a tolerance of +/-20%.  Thus
> the new capacitors have a much better chance of being
> nearer to the design characteristics than the
> original.  The 5 mfd difference doesn't mean anything
> in electrolytics at this high a value.
>
> The silicon diodes in the power supply should be
> changed out at the same time as the capacitors.  The
> replacement diodes have a considerably higher voltage
> rating and current capabilities.
>
> Also, the parts to rebuild the bias supply are less
> than 50 cents and it only takes a couple of minutes to
> replace them.  Therefore, it is best to rebuild the
> bias supply while doing the rest.  Just use the same
> type of diode in the bias supply as is used in the
> high voltage supply.
>
> The mouser part numbers and quantity needed:
>
> 120 mfd @ 450 volts electrolytic capacitor
> p/n 140-LS121M2W-2240
> Quantity needed:  6
> Price $3.14 each
> Total: 18.84
>
> 1000 volt 3 amp diodes
> p/n 583-1N5408
> Quantity needed:  17 (but buy 20 to have spares)
> Price $0.21 each
> Total:  $4.20
>
> 22 mfd @ 160 volts electrolytic capacitor
> p/n 140-XRL-160V22
> Quantity needed:  1
> Price:  $0.20 each
> Total:  $0.20
>
> Total price of parts is $23.24 plus shipping.
>
> Mouser has no minimum order requirements for orders
> from the United States, Canada, or Mexico.  Their URL
> is
>
> http://www.mouser.com
>
> However, ordering over the Internet sometimes adds a
> day, or two.  The sales staff at Mouser definitely
> suggests telephoning because the order is immediately
> processed by computer to the shipping department.
> Their "800" number is (800) 346-6873 and if the order
> is received by 8:00 PM Central time it normally ships
> that evening.
>
> I do not have any connection with Mouser except that I
> order parts from them on average 2 or 3 times a month.
>
>
> Glen, K9STH
>
> Web sites
>
> http://home.comcast.net/~k9sth
> http://home.comcast.net/~zcomco
>
>
>
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