[Boatanchors] 'Stoopid' OT question

[Chuck McGregor]

Phil-
Suggest an ebay search on your power supply number.... if it is Samlex SEC
1223, there are parts kits available, and also prices on a replacement
supply which you might want to compare.  See ebay item:  142415928057

Availability of a repair parts kit suggests this may be a frequent
failure.....You might want to compare with alternative makers.
73
Chuck K7MCG


On Fri, Aug 11, 2017 at 7:30 PM, Phil <ko6bb1 at gmail.com> wrote:

> Hi,
>
> Right now I have a Samlex SC1223 12V switching PS on the bench.  It was
> used on one of the remotes for the club W6BXN repeater system.  Anywhoo, it
> failed, blowing he primary fuse.  Samlex was nice enough to send me a .PDF
> file of the schematic.  Found the output switching transistors (2SC3320)
> are both shorted.  No problem, they're readily available at reasonable
> cost.  Over the past 60+ years I've repaired a gazillion power supplies,
> but not a lot of experience with the switchers, hence the question.
>
> This unit has three 2200uF 25V Caps for filtering of the 12 Volt line.
> Two in parallel right after the rectifier and a third after some filter
> chokes.  The two parallel units are "bulging" at the top, it appears that
> luck was with us and they didn't blow their guts all over the inside of the
> unit.
>
> My plans call to replace them along with the transistors, I'm just not
> sure of one thing.  In a switching supply (runs at 25kHz), do I need to
> order some special "Low ESR" 'lytics, or will everyday run of the mill
> 2200uF 25Volt 'lytics do just fine???
>
> --
> 73 From "The Beaconeer's Lair"
> Specializing in DXing NDBs (Longwave Beacons)
> Phil, KO6BB,  http://www.qsl.net/ko6bb/
> KO6BB/B beacon, ~20W on 28.290 MHz, Ringo Vertical
>
> HF/LF RADIOS:
> HOMEBREW:   7 Tube+Rect 1v3 Regen RX for LF (built 2015)
> Icom:       IC-7200 Xceiver, DSP IF & filters (~2015).
> Kenwood:    TS-450SAT Xceiver, cascaded 250/125Hz Inrad filters.
> 10M Beacon: 2 x Realistic HTX-100's on 28.290MHz
> SDR:        Softrock Ensemble II LF (built from a kit 2017).
>
> ACC:   HOMEBREW  LF-MF Pre-Amp, 8Hz Audio Filter.
>        HOMEBREW  4 Port Antenna Multicoupler, Feeds 4 RX's.
>        ANTENNAS: 88 foot Long Ladder-line fed dipole, 35 feet AGL for
> MW/SW.
>           Active Mini-Whip, 36 Feet AGL for LF/MW/SW.
>           37 foot "Low Noise Vertical", 11 feet AGL for LF/MW/SW.
>           Cushcraft AR-10 Ringo Vertical, 14 feet AGL for 10M beacon.
> Merced, Central California, 37, 18, 37N   120, 30, 6W CM97rh
>
>
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