Hi there. I have a HP8563E unit that suddenly lost its display. After scratching around for a while I found a short CCt cap on the A15 board taking out the -15V rail. Once rectified my display came back but the ref level is way too high causing the trace to always be at the very top of the screen. It goes through its boot up ok and then when its finished the trace goes way up high and stays there. Any ideas here? Anyone had this?
Thanks
Hi Rad001,
It is possible that other components could have broken at the same time or as a result of the capacitor failure. I can point you towards some documentation which might help you in your troubleshooting:
In the 8561E/EC & 8563E/EC Spectrum Analyzer Assembly Level Service Guide, there are some very detailed instructions for testing components on and related to the A15 assembly. Page 618 (586 of the PDF) details the RF assembly of the board, with information on the 10MHz reference on page 623 (591 of the PDF). Block diagrams of A15 are at the end of chapter 10, right after page 585 (557 of the PDF). Page 207 (205 PDF) details proper removal of A14 and A15 (which are hinged together) and 524 (496) lists some test points you can use to deduce the location of the fault.
That's a lot to go through, but hopefully it helps.
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