HP 8643A Frequency Generator Won't Power Up

[bandersen]

Awesome! Does it complete the calibration with no errors? Was just about to post that according to Curious Marc the 8643A schematic has been leaked and scanned

[Chris K]

Originally Posted by bandersen

Awesome! Does it complete the calibration with no errors? Was just about to post that according to Curious Marc the 8643A schematic has been leaked and scanned

Yes I got it on a flash drive from a seller on eBay but the CLIP didn't have schematics for the 2 power boards since they are not made by HP/Agilent. Good to have them though. I did install a new NiCad 3.6V battery so yes, no wait for calibration anymore. No errors...just boots right up. Just blind luck I bought the model that has the leaked schematic. I watched the misaligned connector/blown cap and chip video from CM today. The guy has amazing diagnostic skills.

[Chris K]

Quick question Bob or anyone else who might know this, what direction is the cooling fan supposed to move air…suck air into the cabinet or blow air out of the cabinet? I’m sure someone was in here before me so I made a few assumptions as to what might have been done. The 24V fan leads plug into one of the power boards but the way the fan was bolted to the cabinet, the leads barely reached the pins and when plugged in the leads were almost under tension. I thought maybe someone might have messed with the fan orientation so I rotated it 90 degrees so the leads were much closer to where they needed to go. It made a difficult reinstall of the board a little easier. It’s probably where the fan vibration got introduced. I didn’t turn the fan around to bring air into the cabinet but now I’m thinking who knows if somebody before me had the fan out and put it in backwards? I am certain the reason the fan never ran on this machine is because the tensioned leads fell off the pins when whoever was in here before me tried to reinstall this large sheet of aluminum with circuit boards screwed to it. The clearances are minimal. Pretty long for a quick question! As for the fan…air in or out?