[NLRS] FW: [VHF] HP ESP120 blade power supply issue

[S. Earl Jarosh]

S. Earl Jarosh, N0HZ
Cell:  612.868.1313
Off:   763.545.3275
Home:  763.546.7897
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earl at jarosh.org

  


-----Original Message-----
From: VHF [mailto:vhf-bounces at w6yx.stanford.edu] On Behalf Of Warren via VHF
Sent: Saturday, August 20, 2016 1:05 PM
To: NEWSVHF at mailman.qth.net; ontVHFAssoc_reflector at yahoogroups.com;
VHF at w6yx.stanford.edu
Subject: [VHF] HP ESP120 blade power supply issue


Anyone experienced with the HP 2950W 60A ESP120 power supplies?

A friend has one connected to a Larcan 6M amplifier. It provides about
51VDC, proper bias current at about 4A total. Once RF is applied the DC
voltage starts to rise. Same thing happened with a second power supply also.
Any idea what the problem could be? I've never seen this happen before. The
HP power supply typically powers up without issue for Larcan, Harris, or
Freescale amplifiers.

Here are some of his numbers.

Connected it (Larcan 6M amp) to the brand new (and I mean new from the
manufacturer, complete with the shrink wrap and instruction manual) PSU, and
turned everything on. Beautiful - 51.2 V to the B+ rail, 38.8 V on the bias
line. I checked everything again and applied a small amount of drive - power
came up to 100 W out, B+ rose to 53.3 V (shit!). Added some more drive,
power out about 200 W, B+ now 58 V. Increased drive some more to get about
250 W out, and B+ now at 63.3 V, so shut it down.
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