Need help! My Bridgeport brand dro stopped working

[crafted1]

I mistakenly left my dro on for 3 days and now the display area will not light up. It powers on and the absolute light is on.any thoughts would be greatly appreciated. I have not taken the cover off yet to peek inside.
Thank you

 

[car2]

If the function buttons/lights work, likely culprit is the converter component (may still be available from ERG (Endicott Research Group Inc ERG supports all major manufacturers of CCFL- and EL- backlit LCDs) per below thread) that powers the gas-discharge display modules: see the following thread and excerpt below:
https://www.practicalmachinist.com/...-lathes/bridgeport-dro-246832/?highlight=car2

Probably had nothing to do with leaving it on--its demise was looming. (mine is still working after about 10 years of replacing that inverter; I bought an Accurite replacement system a couple of years ago for the next (final) time the Textron/BP head or readers crap out, so now the old one will probably last forever...


"I've repaired two of these old bridgeport/textron DRO's that had the identical symptoms (and I've seen others). The display digits are flat segmented gas discharge packages (not tubes). The symptom these developed is that the display digits will not light, but other functions lights work. There is a 70 volt (IIRC) converter component (~1x1x1 black potted comp) on the display bd to run the display digits that failed (no voltage to the display digits and could be found--these gas panel digits require a reasonable high voltage to run). Yours may be going bad (or a bad electrolytic cap in dc power supply section) if its taking a long time to turn on. Turns out ERG Inc still makes these inverters (E512-301-CT)- same pinout and everything. Later, also had a loose wire in the encoder pickup which had to be be repaired (required digging in the potting under a scope). I couldn't find schematics for any of these dro's, so if it isn't something relatively easy, probably out of luck if they fail. Mine's been working fine since the converter replacement."

 

[Ray Behner]

Three days! How negligent. I think this is the 20th year for my Sony, and about the same for the Mits.
Oops, 21 years. How time flies.

 

[BT Fabrication]

i dont turn mine off all winter. most likely its the power supply. they crap out caps about 10 yr mark.

 

[car2]

There aren't any electrolytic caps in those old BP/textron DRO heads that I could find. Similarly, I have '95 vintage Series 1 Interact (Heidenhain TNC2500), and the only electrolytic caps are a couple on the driver-board power supply section, and all the boards are very protected with mounts, seals and heavy enclosures--industrial-duty stuff. Much higher reliability it seems than some of the modern cheap looking PCB's in current CNC controls shown on here taken apart (replete with cheesy memory coin-batteries soldered to the PCB (guess that's a good money-maker for the service-folks, replacing pcb/batteries and when folks lose their parameters). That TNC 2500 has 3 AA batteries accessible via an easily accesible external screw-cap; although I change them every 1.5 year, they last forever (still over 1.5 volts when removed every year and a half)..and it gives you plenty of warning if the voltage drops on the batteries.

 

[moonlight machine]

Three days! How negligent. I think this is the 20th year for my Sony, and about the same for the Mits.
Oops, 21 years. How time flies.

Yeah Ray, my Acurite has only been off a few times when we had a power outage since I bought it in 1996!

 

[crafted1]

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Thank you Car2 , I am looking into your suggestions and will keep you posted. I enjoy solving problems and not adding to the land fill every time something stops working! I appreciate you sharing your knowledge with me!
I friend gave me an acu-rite mill D200 dro display and I’m considering doing adaptor cable to go from the round six pins from my old Bridgeport/textron glass scales to the standard modern 9 pin of the newer displays. I needed a quick fix to finish a project and I really don’t want to replace the glass scales on this machine.
Thank you