Does anyone have a Hitachi V-223 oscilloscope service manual? - Page 1
Forum section: electronics / testgear

author: microbug
author_rank: Frequent Contributor
timestamp: March 25, 2014, 07:07:21 am
content: Hi,I got a Hitachi V-223 'scope on eBay last year, but it is out of calibration by some way. I can't find a service manual online - only an operation manual which isn't much help.Does anyone either have a digital copy, or a physical copy they'd be willing to send me (or to scan into a computer)? I live in the UK but I'm happy to pay for postage from abroad.I have seen that there is a copy of the service manual on eBay but $48 + $22 shipping is too steep for me.Thanks in advance!

author: grumpydoc
author_rank: Super Contributor
timestamp: March 25, 2014, 08:17:30 am
content: Google harder!!Actually I can't find a free download. The manual+diagrams is on Scribd though if you don't mind getting it there.

author: microbug
author_rank: Frequent Contributor
timestamp: March 25, 2014, 03:40:13 pm
content: That's the operation manual: I've got a digital copy of it already. I emailed Hitachi, but all they could find in their database (they discontinued their oscilloscopes years ago) was the operation manual.Since it's unlikely that there is a digital copy of the service manual online, I'm resigned to the fact that I will probably have to get a physical copy somehow: does anyone here have one they would be willing to sell / give away?

author: grumpydoc
author_rank: Super Contributor
timestamp: March 25, 2014, 03:46:47 pm
content: QuoteIt has the schematics at the end - at least appears to as the Scribd preview isn't that great. There probably isn't a separate service manual

author: microbug
author_rank: Frequent Contributor
timestamp: March 25, 2014, 03:51:04 pm
content: There is - it's referenced in the operation manual (as far as I remember) and there's one on eBay, but it's pricey for me in the UK: $48 + $22 shipping (I'm 14 years old). There are service manuals for similar models online, and I have calibrated it to one of those as best I could, but it's still out of calibration in some areas.

author: KJDS
author_rank: Super Contributor
timestamp: March 25, 2014, 04:13:33 pm
content: I've not looked inside a V-223, but every other Hitachi scope I've looked inside has had a silk screen marking the function of each pot.

author: microbug
author_rank: Frequent Contributor
timestamp: March 25, 2014, 04:15:02 pm
content: It's the same in the V-223. I could go round every pot, work out its function and adjust it accordingly but it would be much easier with the service manual.

author: grumpydoc
author_rank: Super Contributor
timestamp: March 25, 2014, 04:17:14 pm
content: You don't really need to work it out if the functions are marked on the silk screen.Do you have a levelled sine wave source and a fast rising square wave source to do the adjustment.

author: microbug
author_rank: Frequent Contributor
timestamp: March 25, 2014, 04:18:22 pm
content: If an AD9850 module from eBay is good enough then yes, I have both.

author: grumpydoc
author_rank: Super Contributor
timestamp: March 25, 2014, 07:29:26 pm
content: QuoteHard to say.If the timing source is a crystal then that should be more than adequate to set up a 'scope timebase.Assuming that the square wave output just comes from the comparator in the AD9850 then it has a spec of 3ns rise time for 5V supply and 3.5ns for a 3.3V supply which would be OK for the transient response. However if you aren't sure what your doing I'd stay away from anything labelled HF compensation (and, in fact, anything which looks like a trimmercapacitorin the 'scope) - chances are it won't be far enough off to worry about.The biggest area that I'd have my doubts would be the amplitude accuracy which will rely completely on how accurate RSETis and is probably not truly good enough to set the vertical gains even if there's any decent spec for what the full scale voltage is meant to be. However you can do that with a DMM and power supply.Oh, I've just seen your other thread about calibrating the timebase in your 'scope - definitely go with the AD9850 for timing, the internal "test" signals are intended for adjusting x10 probe compensation and typically are not very accurate at all. If anything I would trust the amplitude of that signal to be tolerably close to .5V but the frequency could easily be anything up to 25% or 30% "off" from the nominal 1kHz.Edit: It's worth remembering that a 'scope isn't intended to be highly precise - typical timebase and vertical deflection accuracies are within a few percent