BECKMAN TECH 360 schematic circuit diagram

[Voxman]

Hello Everyone,
I’m trying to install an LED power indicator on my Beckman 360 multimeter.
My problem is the power switch that turns meter on and off doesn’t receive the 9 vdc battery voltage.
When I measure the voltage on the switch, it is about 7.58vdc. So I assume it’s because the switch is
configured differently that an ordinary power switch. The switch itself has 5 terminals that have NO voltage on any of the terminals until it’s powered on.
I need a schematic to figure out why and where I can tap into the 9vdc that is switched.
Any help is appreciated!
Thanks
Voxman

[floobydust]

The on/off switch opens the battery pack (-) to GND, which might be confusing.
The multimeter IC has a 6.5V regulator which powers everything except the Ohms source gets raw 9V.

I haven't seen a Beckman service manual on the web, I used to have a paper one but would have to dig for it.
The TECH 350/TECH 360 Owner's Manual has a tiny partial schematic.

Battery lifetime is rated 12,000hrs so adding an LED seems unusual.

[Voxman]

Floobydust,
Thanks for posting the info. I went ahead and tapped into the switch voltage and it is working fine on a prewired, normally 12vdc powered LED. There isn’t much room to install a LED but did find a space.
As far as the current drain on the 6 D size batteries, you’re absolutely right that is almost inconsequential but I have a bad habit of leaving it on accidentally for days on end. The LED will alert me if I leave it on…
BTW I love this meter…it has been such a dependable and accurate meter for almost 40 years now!
Thanks anyway for the info…appreciate the reply.
Voxman

[floobydust]

I have scanned the Beckman Tech 350/Tech 360 manual but the page size is terrible, really wide and narrow. Next is to get my buddy with Acrobat to put it in a single pdf. Otherwise I couldn't find it on the web. I'll PM once finished.

I've got a Tech 360 to repair, one 10uF blue electrolytic capacitor getting bad leaked a bit after 40 years and LCD a bit wonky. Might be worth it to retrofit an Eneloop AAA 9V pack for it.

[blacksand]

Would also like a copy of the schematic for Beckman 360 please. Can you post a link or pm a copy.

Dan

[floobydust]

This is the Tech 360 schematic scan I have from the tiny owner's manual booklet.  The original print resolution was a bit low.
Also a pic of an eBay listing page for the service manual but somebody scooped it up before me
It shows Beckman Tech 350, Tech 360, Model 3050, Model 3060 bench multimeters PCB layout.