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Bo-Lennart Bo-Lennart is offline
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Default Need a service manual SENNHEISER UPM 550-1

Den onsdag 7 mars 2018 kl. 18:25:00 UTC+1 skrev Bo-Lennart:
Have a SENNHEISER UPM 550-1 (audio level-meter). My problem is that -14Vdc from the power-supply board is goes upp and down to nearly 0 Vdc. If I take out the board labeled B15, the -14Vdc is stable. And I can use the instrument as a AC-rms voltmeter. No problem. But something happen the I re-plug the board B15. The B15-board have something to do with the CCIR-filter (I guess). But I need a service manual to find out. Maybe someone out there, know exactly what's wrong here.

Best regards from SWEDEN
Bo-Lennart Karlsson
Falun, SWEDEN


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