Hello all,
I have had luck before here, at DiyAudio, with tools and equipment.
As many here I shop for used equipment in eBay with varied levels of success. I bought long time ago (2018) a Keithley 197A that is in great cosmetic and functional condition. It is a great meter for the price, when you can get a deal, and is very precise. I got it for less than $100 shipping included.
As most meters of this era, and particularly with these, the EL does not work. It has a power button in the back that enables this function. Using an EL driver from an old Sencore VCR test unit, to validate that the EL element is functional, and it's the driver that has the problem. I contacted Keithley, now Tektronix, and they mentioned the driver is not available. Efforts to open it up to repair were unsuccessful, as it's imbedded in some resin and difficult to troubleshoot.
Interesting enough, the Sencore has a discrete circuit with one transformer and one transistor and appears to operate also from a 5VDC supply. I am surprised no devices are available to replace this module for cheap and already to go. It is true most new equipment with LCD displays now use LED back lighting, but I was hoping for ideas or if someone has solved this problem to point me in the correct direction. A nice backlight would help the viewing of the Keithley's LCD display better
Any ideas are welcomed.
I have had luck before here, at DiyAudio, with tools and equipment.
As many here I shop for used equipment in eBay with varied levels of success. I bought long time ago (2018) a Keithley 197A that is in great cosmetic and functional condition. It is a great meter for the price, when you can get a deal, and is very precise. I got it for less than $100 shipping included.
As most meters of this era, and particularly with these, the EL does not work. It has a power button in the back that enables this function. Using an EL driver from an old Sencore VCR test unit, to validate that the EL element is functional, and it's the driver that has the problem. I contacted Keithley, now Tektronix, and they mentioned the driver is not available. Efforts to open it up to repair were unsuccessful, as it's imbedded in some resin and difficult to troubleshoot.
Interesting enough, the Sencore has a discrete circuit with one transformer and one transistor and appears to operate also from a 5VDC supply. I am surprised no devices are available to replace this module for cheap and already to go. It is true most new equipment with LCD displays now use LED back lighting, but I was hoping for ideas or if someone has solved this problem to point me in the correct direction. A nice backlight would help the viewing of the Keithley's LCD display better
Any ideas are welcomed.
Hi guswin95,
I've never worked with EL, but maybe here's a place to begin:
https://ww1.microchip.com/downloads/en/DeviceDoc/hv816.pdf
Sounds like a fun project. Good luck!
I've never worked with EL, but maybe here's a place to begin:
https://ww1.microchip.com/downloads/en/DeviceDoc/hv816.pdf
Sounds like a fun project. Good luck!
I have used EL in the past. You probably need about 100V at 1 KHz to drive the el panel. Since its a technology that seems to have passed I'm not sure what you can find. I did find this: https://www.ebay.com/itm/2652439738...3aBHRnsww5xgKEfIQ%3D|ampid:PL_CLK|clp:2047675 which may nbe able to work for you if you have 12V available. Search eBay for EL panel.
Thank you for all the suggestions. I had looked at the eeblog posting with interest. Unfortunately, his solution is the opposite of my need. My driver is bad and the EL is still good. I find in eBay and AliExpress lots of cuttable panels but no driver small enough to fit in the front of the instrument. I got to try an edge LED plastic option and it looked promising except it did not match the size of the plastic backing.
I used a cheap dead PZEM-061voltage panel meter as a donor and was encouraged with the simplicity it would be to use an edge LED, but the design of the plastic backing is difficult to cut and not create light leakage. The dimensions meant it was too short for this application.
Will continue to investigate. Thanks to all
I used a cheap dead PZEM-061voltage panel meter as a donor and was encouraged with the simplicity it would be to use an edge LED, but the design of the plastic backing is difficult to cut and not create light leakage. The dimensions meant it was too short for this application.
Will continue to investigate. Thanks to all