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G8MNY > TECH 27.05.16 12:13l 119 Lines 4530 Bytes #999 (0) @ WW
BID : 6234_GB7CIP
Read: GUEST
Subj: 12V 75A Del SMPSU Mods
Path: IW8PGT<CX2SA<GB7CIP
Sent: 160527/0727Z @:GB7CIP.#32.GBR.EURO #:6234 [Caterham Surrey GBR] $:6234_GB
From: G8MNY@GB7CIP.#32.GBR.EURO
To : TECH@WW
By G8MNY (New May 16)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)
I bought this Del Model 7000815 server SMPSU, at recent car boot sale. I needed
75A @ 13.8V for my HF linear. So this seemed to meet the requirement, instead
of floating a battery in the shack. But I have always wondered if a SMPSU would
be quiet enough for this application?
____________________________________
/ /|
/___________________________________/ |
_| | |
| | |2 rear
| | |
MAINS |/|intake
IEC | |
LEDs | |fans
ÀÄ¿ | |_
Air| |/ /| rear
Vents| /__/ / connector
|______________________________________|/
Powering up gives just the power connected green LED, until the external links
are sorted out. When 12V is on another green LED lights, A fault yellow LED
indicates overloads etc.
2 Rear connector links are needed get the 12v going.
REAR CONNECTOR
1 5 9 13 17 21
: : : : : :
: : : : : : ] [ ] [ ] [ ] [ ] [ ] [
4 8 12 16 20 24 0v 0v 0v 12 12V 12V
Pin
1 3.3V PSU control (+ve = on)
2-3 0V
4 Start voltage (+6v) link to pin 1
7 Fan speed link to 0V for slow.
8 put to +12v for +0.6V more volts.
9-12 0V (3.3V rail)
13-16 +3.3V output (6A)
23 12V PSU control (0v = on, once 3.3V is on)
MOD TO RAISED OUTPUT TO 13.8V
This involves disconnecting the mains, removing the steel cover locating the IC
& some fine soldering (large surface mount IC pins).
== == == == == == == ==
____ ____ ____ == == == == == == == == ==
/ \ / \ / \ 4 MAINS MOSFETS 2 MAINS MOFETS
/ \/ \/ \
MAINS HT CAPS | ÚÄÄÄÄÄÄÄ¿
\ /\ /\ / ³| ± | ³ 12
\____/ \____/ \____/ ³| ± | ³ ,,,,,,,, Carefully solder a 39K between
== == == == == == ³| ± | ³ ÚÄÄÄÄÄÄÄÄ¿ the 12v SMPSU IC's feedback pin
== == == == == == ³| ± | ³ ³39k' ³ pin 1 & earth pin 12 the output
4 MAINS MOSFETS ÀÄÄÄÄÄÄÄÙ ³| ³ is raised to 13.8V
ÚÄÄÄÄÄÄÄ¿ ÀÄÄÄÄÄÄÄÄÙ
³| ± | ³ 1''''''''8
³| ± | ³ ___________________
³| ± | ³ [ o o o o o o o o o ]
³| ± | ³
ÀÄÄÄÄÄÄÄÙ
DRIVER TRANSFOMERS
Be aware when testing, most of the components are at mains potential! Use an
mains isolation transformer if doing live testing.
MOD TO SLOW FANS DOWN WHEN COOL
I used a 100k thermistor in a heatshrink sleeve, placed near the front of the
PSU in the exiting air to control the fan speed...
ÚÄÄÄ<+12V (e.g. top of CURRENT shunt)
1K
³ As the thermistor warms up it gradually
Therm increases the fan control voltage.
ÀÄÄÄÂÄÄ>pin7 The 2k2 mounted on the external pins sets
2k2 the fan's slow running temperature.
ÀÄÄ>pin3
This mod also stops the fans spinning at full speed is a battery is paralled,
but there is still some battery drain on no mains.
MOD TO PTT SWITCH THE 12V.
As I only use this SMPSU for my 400W HF PA & it is 0V controlled, it can be
directly connected (Via a resistor & diode if needed) to the rig PTT-PA control
line for less QRM on Rx. (N.B. 3.3V SMPSU still runs!) But this may not be
quick enough?
___ _______
Mic>Ä´RIGÃÄÄÄ´400W PAÃÄ>ANT
³pttÃÄÂÄ´ptt ³
ÀÄÂÄÙ ³ ÀÄÄÄÂÄÄÄÙ
_³_ ³ __³__
³PSU³ ÀÄÄ´SMPSU³
ÀÄÂÄÙ onÀÄÄÂÄÄÙ
MAINSÄÄÄÁÄÄÄÄÄÄÄÄÄÙ
ON AIR
All seems every good, DC is better regulated than the battery system. The QRM
is only very slight on 160/80/40m with a decent aerial, & mostly below my
neighbour's TV/PC QRM (as it seems to be on the same spot frequencies).
With a spectrum analyser & ferrite ring pickup the cable RFI was very low. But
magnetically quite loud near the box case, as the earthed steel case is very
thin.
Also see my Tech bul "T500M 12V 500W HF Linear"
Why don't U sent an interesting Bul?
73 De John, G8MNY @ GB7CIP
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