So, I'm rehabilitating a display case for a retail store.  It's from the 1940s or 50s and has a single F30T8 preheat lamp.  I thought I just needed to put a modern grounded cord on it, but discovered someone had robbed the ballast!  I can see the outline in the gear tray, it was a nice HPF unit, a foot long.  I see a few options to get this thing working, the first one is this:  I have a rapid-start ballast for a 32W or 40W circline lamp.  I can connect one red and one blue wire from the ballast to the lamp and keep the starter circuit connected to the other pin of each side.  Is the lamp running voltage close enough to a 32W circline for this to work?  Is there enough preheat current from this ballast to make the lamp start properly?  It is class P, and I can see if it's running hot when I try it out. 


I have one more small-town hardware store with dusty shelves to check for a NOS preheat 30/40W ballast, but if the circline ballast doesn't work, I may need to fix it in a way that's less vintage involving a direct-wire LED tube or single-tube mode with a 2x32W electronic IS ballast.

BTW, the store I checked today has a NOS AdLite 2x40W preheat ballast (the kind with no starting compensator), and two F72 Power Grooves.

Thanks,
Matt

Matt, how much did they want for the 2x40 Ad Lite ballast?  I would love to have it if it is reasonably priced (around $15 or less). 

The 32W Circline is, in fact, electrically similar to the F30T8. Now, whether the RS ballast will provide enough preheat current, I don't know. You could always try eBay for a NOS preheat ballast, though. These are all the models I'm aware of:

GE/Valmont
- 8G3706
Advance
- L-140-F
- L-140-F-TP
Universal/MagneTek
- 202
- 202-B
- 202-B-TC-P
Robertson
- S40B
- S40BP

They want $45 for the Ad Lite ballast.  Not sure how negotiable the price is, but it has been on the shelf a long time.

Nicksfans, thanks for the specs on the circline ballast.  I ended up getting a 3ft LED direct-wire tube so I don't need a ballast.  Not as original, but works for the time frame of the job and is less than the NOS ballast I saw on eBay.

GE F30T8 lamps will light on rapid start. Sylvania won't. I think Philips will. 

I had some interesting behaviors with T8s and SRS gear (which is no meant for them)

In one of them, a T8 tube would start cold but not restart after it warmed up, much like a HID lamp. Other times just randomly lighting/not lighting

i have seen dual rated ballast for f30t8/fc32t9 tubes.
too late to try now but it would have probably worked.

GE F30T8 lamps will light on rapid start. Sylvania won't. I think Philips will.

Generally, F30T8 tubes are intended for preheat ballasts rather than rapid start ballasts.

@WorldwideHIDCollectorUSA:
True, but in some cases they will fire up and run just fine on RS.

Pretty interesting. You get a similar experience with running probe start metal halide lamps on most mercury vapor ballasts if you do not use a European 750v-1000v 2 wire parallel ignitor. Sometimes the probe start metal halide lamps fire up just fine on those mercury vapor ballasts just fine without the ignitor, but the lamp will become less likely to start as it ages.