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DEC VT330+ service manual or schematics wanted


New Member
Sep 27, 2023
I have some broken VT330+ lying around and want to give it a try to repair.
It has an interesting graphics mode and I would love to put back the thing to life.

Strange thing is that I could not find service manual or schematics for it on the internet. It looks like it was never scanned and uploaded by anyone.
I found somewhere the DEC document id for the service manual, which is EP-VT33R-SV-001 .
But as said, nowhere to find.
Is there some way to get hands on that manual? E.g. micro fiche or whatever... any hint is appreciated

From other DEC devices I know that there are "engineering drawings" which include schematics. Maybe someone has a hint to this too.

I already have started my repair job, and will post questions to that topic in another forum post.

Last edited:
Yes, thats the VT330 engineering drawings document.

The VT330+ looks from the schematics and used parts very different. VT330 has BU405 in HV section, VT330+ has BU406. VT330+ has a Power MOSFET IRFPE40 in its PSU section, where VT330 has nothing like this. Flyback transformer also is different.
So the VT330 can only roughly serve as a related document...
If you find the manual, could you forward a copy to me.

If you only find a hard copy I can scan it and return it to you.
I did an extensive search for the schematics and finally found the service guide EP-VT33R-SV-001, also named(?) EK-VT33R-SV-001. Alas, it has no detailed schematics inside.
But good news is that this document already exists, despite listed as non available online.

I've created an issue report at Manx Github site and assume that they will fix their web site to list this document as being online.

The document location is:

The issue I've created on Github, with link to the document is here:

Great search foo; thanks for sharing this link. Looks like it's worth rooting through https://manx-docs.org/collections/antonio/dec/. Unfortunately the file naming system is often inscrutable and Manx is beholden to someone scraping the appropriate metadata from the file content in order to include it in their search algorithm, which I infer didn't happen in this particular case. There is an automated interface for individuals to accomplish this when adding documents, and there is a automated interface that currently accomplishes this for all new documents in Bitsavers since Al has a consistent file-naming convention.
I have a VT340 that passes self test, but has no video. The link you posted has given me new 'leads' in my quest to revive this terminal. Thanks.
Great, good to hear!
For VT340 fault in HV section, there is some info here https://michelswunderland.de/solderiron/vt340.html, you probably need to translate from german.

I was meanwhile able to repair the VT330+ so that it displays data again. The HV section was ok, but two capacitors in power supply section were faulty. The image is there now, but not very bright, so I intend to look further into this later. But for now I am glad that it works again at all.