Hitachi Oscilloscope V695 etc. - Page 1
Forum section: electronics / testgear

author: chrisnotton
author_rank: Newbie
timestamp: March 25, 2023, 10:39:03 pm
content: Good evening all,I have just acquired one of these on Ebay. I used to have one (that was stolen) in the 80's and found the auto-timebase feature particularly useful for audio applications, and lining up tape machines etc. I have been a Tek guy ever since but recently I find myself working on tape-machines again!This bargain popped up so.............The scope I bought has a few dirty switches but the only annoying thing is that the trace horizontal is off-centre by about 5mm. I have read all the posts i can find and downloaded the service manual but cannot see an obvious trimmer for this alignment.Does anyone have the alignment procedure, or know where this adjustment is located? I will have to disassemble somewhat to access the dirty switches but I would imagine that the adjustment must be moderately accessible for calibration.Thanks in anticipationChris

author: grumpydoc
author_rank: Super Contributor
timestamp: March 25, 2023, 10:47:49 pm
content: When you say "trace horizontal is off-centre by about 5mm" what do you mean exactly?Photo would be good.

author: chrisnotton
author_rank: Newbie
timestamp: March 26, 2023, 08:38:26 am
content: The centering; the traces start 5mm. to the right of the graticule. No photo available at the moment. Sorry for the ambiguity! 😉

author: grumpydoc
author_rank: Super Contributor
timestamp: March 26, 2023, 02:17:07 pm
content: OK, so you've only got half a trace?Can you use the h.pos control to move the trace (that's selected with the function toggle switch)Double check you're not in a delayed sweep mode and x10mag is off.

author: chrisnotton
author_rank: Newbie
timestamp: March 26, 2023, 09:11:25 pm
content: I have tried but there is not enough adjustment. I have just found the alignment procedure in a different online manual.I am going to study that.Thanks

author: grumpydoc
author_rank: Super Contributor
timestamp: March 26, 2023, 10:00:42 pm
content: OKHave you checked all the power supply voltages?The first thing the procedure does is ask you to position a dot in the centre of the graticule in x-y mode so that you can adjust the CRT bias.I presume you found some of my old posts on these 'scopes eghttps://www.eevblog.com/forum/testgear/teardown-hitachi-v1065There is a trimmer for H Pos Start - it's RV 807 on the schematics that I have and it's on the CPU/horizontal board - you can see the label for it on the silkscreen in my photos. The pots on that board can be accessed from the bottom of the 'scope as the Y board is a bit shorter (again, see the teardown photos for the CPU board - RV807 is readily visible).PS: If you feed a signal in - the probe "calibration" square wave will do, is the trace basically OK, just too far to the right. or is it distorted at all?

author: chrisnotton
author_rank: Newbie
timestamp: March 27, 2023, 02:43:13 pm
content: Thanks,I'll check the PSU voltages and start from there. The scope seems to function normally except all the traces on the display start after the graticule. I have read your teardown posts, Very helpful!I'm away at the moment so will have a go when I'm back.Thanks for your helpChris