Valhalla 2703 AC Voltage Calibrator - Help needed to identify part. - Page 1
Forum section: electronics / general

author: TheDefpom
author_rank: Frequent Contributor
timestamp: August 06, 2018, 10:42:21 am
content: Hi All,I picked up one of these units a few months ago, I found that there is a capacitor completely ripped off one of the boards, the vertical board on the right hand side, the capacitor is right at the front edge of that board, towards the upper section, number is C122, can someone have a look in their unit and tell me what that part is, the marking looks like an electrolytic or tantalum but the service manual says it is a different type of only 470pF, which doesn't really match up, so if someone could pop the covers and confirm both the type, voltage and value of what is actually there that would be great!I will be doing a repair video on the unit once I get enough time to dig into its issues, basically it drops into standby when higher voltages are selected, so its probably some leakage thing, I am currently waiting for new caps and a new fan to a arrive before I start working on it, I will do the basic stuff first!

author: Gyro
author_rank: Super Contributor
timestamp: August 06, 2018, 10:50:10 am
content: You might be best moving this topic to the Metrology section, that's where the Valhalla owners hang out - and particularly if you are planning to do a video on it.

author: Gyro
author_rank: Super Contributor
timestamp: August 09, 2018, 08:58:39 am
content: @Simon:I see you have locked the OP's duplicate thread in the Metrology section. In my reply above, I suggested that hemovethis thread there. He has obviously had difficulty in doing that or not understood.It would probably be best for forum 'tidiness' if you could either delete the locked thread and move this one to Metrology, or delete this one and unlock the other one, removing your locking reply too.[Edit: Either way, I think he's going to find more Valhalla owners in the Metrology section.]Chris

author: e61_phil
author_rank: Frequent Contributor
timestamp: August 14, 2018, 02:47:49 pm
content: Do you still need the pictures? I could open my Valhalla 2703 if needed.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: August 14, 2018, 07:39:04 pm
content: Hi, yes I still need to know what that cap is, thank you.

author: e61_phil
author_rank: Frequent Contributor
timestamp: August 18, 2018, 07:10:20 pm
content: Sorry, it took a while to find some time to remove the unit from the stack and open it.C122 isn't assembled in my unit and it looks like it was never assembled before.My unit has also some problems: The output voltage is unstable in the range of 200ppm. But it stays on. If you need some measurements or something else just say so. The unit sitting on my bench without the cover at the moment.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: August 18, 2018, 07:26:21 pm
content: Thank you for taking the time to have a look, it looks like maybe I don't need to worry about that missing capacitor then.I will be doing a live stream on my YT channel in about 30 minutes, I plan to try fixing a HP6181B DC current source, but if there is time afterwards I could have a go at the 2703 as well.I will let you know if I have any specific questions for test voltages etc. thank you.