Yokogawa 2558 AC Voltage standard Service Manual?

[Zermalmer]

Hi,
I search for the service manual of the 2558

Looks like it is also a kind of the lost manuals 

[dl1640]

what is wrong with your 2558?

[Zermalmer]

Hi,
I wanted to check the adjustment procedure, because the device slowly drifting out of specification.
I think I have to adjust it next year.
Also the 100mV and 1V range are unstable or they where without function. (Can't actually remember).
In this case the not working ranges are not a problem, because the user of the device didn't need them.
But if I go for an adjustment I also want to check if I can fix this two ranges.

add:and the red LED for the state of the output is flickering/stop to light from time to time while switching rotary switch.

Best regards
Andreas

[dl1640]

instability may caused by relays in output section, please try to clean or replace them

[Zermalmer]

Thanks.
Schematics (if they are in the SM) naturally would make it a little bit easier to search and identify locations in the device.

[dl1640]

first of first, do proper cleaning and carry out voltage inspection per attached

[Zermalmer]

Thanks for your help...
Difficult for me to take action on the devices, because they are only used partly and have to be returned close in time back to production 

Today I had a 2nd 2558 on desk and there also the 100mV run out of spec. (but here not needed in production enviroment)
All other ACV are within spec... also ACI are in good condition.
Only have to check the 400Hz ACI on hi amps again, because frequency stable reference leaved for calibration

But I have more to come... so (if other work allows it) I maybe will have the chance to get at least one of them full functinal within spec and then get the others piece by piece fully back... but it will take time.

You know... managment decisions... "is it needed with all the effort or does partly calibration is ok in this case?" and you know the answer if they request needed time to get them full up.

[dl1640]

we dont worry about out of spec, we worry about unstable output
this monster is 1980 product it is difficult to get components for replacement, maybe

i have the manual but i am sorry it cant be disclosed to you 100%
if you have specific requirement in the future, let me know, i will help to look up some info for you

cheers

[Zermalmer]

Thanks for the offer.
Will get in touch with you if I have further questions.

[giovannirat]

Still looking for a service manual for YEW (Yokogawa) 2558 AC.

Especially the part with the adjustment procedures would be helpful....

Thanks.

[dl1640]

 :)Now use 2558A, closed case adjustment .

[TiN]

Yokogawa 2558 manuals and some others made it to FTP repository
Thanks to contributor 

[surachoke]

instability may caused by relays in output section, please try to clean or replace them

Hi,

I have the issue with 2558 old model. At some certain range, the display will be blinking and output is turn offed.

As you mentioned that the relay in the output section may need to be cleaned or replaced.

There are two visible relays on the board (big one and smaller one). Do these relays on the output section?