[time-nuts] HP 58503A Flashing Front Panel LEDs

Michael Jasper michael at tarkka.co
Thu May 3 14:29:12 EDT 2018


I recently purchased an HP 58503A from eBay. When I power it on, with or without an antenna, the power LED illuminates on the front panel, followed by each LED one at a time. Then, after a moment, the unit alternates between all front panel LEDs being illuminated and only the power LED at a rate of about once every 3 seconds. I opened the unit and checked the rail voltages. I have 5.22V, +15.01V, -15.00V. The oven is warming. There are some LEDs on the board near the antenna jack and I have two red illuminated and a single green. I can’t get anything on the serial port.

Has anyone seen this before? I have a 30 day ROR but I like this model and would love to fix it if anyone has any advice.


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