Use HP DSP-1200SB A a a power source to ham equipment

[axm1955@yahoo.com]

Hello all,

Acquired a couple HP DSP-1200SB A server power supplies and would like to adapt it (as I did with previous HSTNS-PD18) to supply my ham radio equipment, but have been unable to locate any diagrams on the unit.

The actual PN is 656364-B21 and sources on the internet have stated if was Gen 6 of the DSP-1200 series of supplies.  As with most other hot plugable units I can easily turn it on, but as with all other server supplies it's set to provide 12V DC to the server circuitry, so wondered if anyone in these forums may have some additional technical information I can use to accomplish my goal.

Many thanks in advance for any useful information on this power supply.

[bob91343]

Well, it depends.  I assume you want to increase the 12V to 13.8V.  That should be simple once you reverse engineer it.  There should be a resistive divider somewhere that you can alter.

The tradition of supplying schematic diagrams has ended.  Seizing on that, now manufacturers have decided to refuse requests for them.  Their cost to send one is incidental, and would improve their image.  But they are adamant as far as I know.

[TheMG]

Unless you're also float charging a backup battery, there should be no need to modify the output voltage, most gear should perform normally on 12V, since that is the nominal voltage when running from batteries that are not currently being charged (vehicle with the engine off, backup batteries during a power failure, portable operation, etc).

[MartinL]

The 12V supply from a switch mode PSU intended for server use might be quite noisy, incidentally. These supplies are designed primarily for high power rather than smooth output.

Whether that's an issue will depend on the equipment you want to supply.

[Melt-O-Tronic]

MartinL is very correct.  Another problem that makes nearly all computer switching PSU's a poor choice for ham radio is that they are optimized for continuous power into a non-varying load.  Even if the DC output is clean enough at high power (transmit), when the power demand is low (receive), the PSU noise tends to dominate the output.  There may be exceptions to this, but I've never encountered one.