开云体育

Hi Alberto!

Your scope powers up correctly. The SRQ light stays on because a power cycle was detected. This can be cleared via GPIB or the Keyboard (see manual).
You can ignore this.

As far as I can see there a two errors:

1: ? think the trouble with the jumping/collapsing display is an analog problem - most likely a very simple fault like a dirty/defective potentiometer.

2: The keyboard section is not that complicated. It's descripbed in the "Theory of Operation" section of the service manual.
You should be able to diagnose it without the signature analyzer. Check the wiring to the front panel first.

Holger

Tnx Holger (and others)!

I will study more deeply the service documentation, because I didn’t note an easier troubleshooting approach to the digital section. I am just equipped with the signature analyzer, but I understood that it was not the only tool…

If you are curious about the issue that I need to fix, you can visit my Webpage that I’m dedicating to my 7854:

Alberto

I've temporarily owned such a system a few years ago. The pictures on Tekwiki show that system. But it's not that easy. On top you'll need a terminal and a compatible signature analyzer. And some components like the signature tables (and maybe the diagnostics ROM) have to be matched to the hardware revision of your 7854.

The diagnostics ROM board also contains some stand-alone diagnostics routines which are helpful for calibration and some digitizing problems.

I've uploaded the involved firmware roms and scans of the manuals to tekwiki. I think the vintageTEK museum is still selling a clone of the diagnostics ROM board.

But in my opinion it's way easier to diagnose the system "by hand".

Holger

Sorry, nothing here like that

I looked for one of these a decade or so ago and didn't find anything.

DaveD
KC0WJN


On Tue, Apr 1, 2025 at 02:05 Alberto, IZ2EWV via groups.io <iz2ewv=
[email protected]> wrote:

Did I put a silly request? Nobody knows what I’m looking for or it’s
nowadays so rare that only museums and some collectors keep that equipment
closed inside a display case?
Thank you for you attention.
Alberto

Did I put a silly request? Nobody knows what I’m looking for or it’s nowadays so rare that only museums and some collectors keep that equipment closed inside a display case?
Thank you for you attention.
Alberto

Hello friends,
I’m looking for the service tools needed for the digital portion my tek 7854: the MicroLab I (067-0892-00), the Diagnostic Test Interface (067-0911-00) and the Diagnostic Memory Board (067-0961-XX).
Interested in hiring as well buying them, for troubleshooting an issue that started recently…
Tnx in advance!
Alberto