Products > Test Equipment

Modding a Keithley 197

<< < (7/7)

rwzahora:
My 197A had a very weak backlight so I thought I'd look into replacing it.  The old panel was a Loctite LSI 37269-1 as shown in an earlier reply.  It is 19mm x 86mm.  I purchased a panel from eBay (https://www.ebay.com/itm/393103760354?var=662007375026) and cut it down on three sides and nail-polished the edges.  It works and the light is much better than the original unit although I would have liked it even brighter.  The voltage to the panel is 76Vac measured with a multimeter and the drive is triangleish at about 370 Hz.

jupiters_spot:
Reading through this thread it seems that:
- the 197A has a backlight, and some here have needed to replace the inverter driver to supply the correct voltage to the electroluminescent backlight
- there aren't any posts about adding a backlight to a 197 (as opposed to 197A) display.  Did I miss such a post?

Adding a backlight to a 197 appears to involve two primary steps: install appropriate inverter to drive EL strip, and trim/seal/install EL strip behind LCD display.  All of the EL drive inverters I see either require 12V DC or 120V AC, and I'm not sure I see a convenient source of switched power of either sort in the base 197.  I'd want the backlight to turn on/off with the meter's power button so I'd need to power the inverter somewhere after the meter's power switch.  If anyone has installed an inverter and EL backlight in a base 197 (not the 197A), please share with us how you powered the EL drive inverter and where you managed to stuff the inverter into the meter's case.

tooki:
A 197 display upgrade has been a project on my to-do list for a few years. :p

I don’t think there’s much sense in using EL these days, since LED is so much easier to drive.

Long-term, an entire replacement display board, using a microcontroller to decode the original display signals and reformat them for some modern display, is likely a smarter way to go. (The work to decode the original display signals is already complete.)

jupiters_spot:

--- Quote ---Long-term, an entire replacement display board, using a microcontroller to decode the original display signals and reformat them for some modern display, is likely a smarter way to go. (The work to decode the original display signals is already complete.)

--- End quote ---
I'm intrigued.
Looks like someone has done it: https://www.reddit.com/r/electronics/comments/pkknvk/keithley_197_with_oled_display_upgrade/

Navigation

[0] Message Index

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod