Are you sure you're not using polarised bulbs that need to be inserted the right way round? Although, if that was your issue I guess you'd have a failure rate higher than 15%..go math. I have found about 1/100 failure rate, if that.

I find about 1 in 30 are duds, polarized or not.

did you bend the wires on the leds. sometimes they don't make a connection in the socket. g.l.joe

15% seems a little high (unless we are talking about red color).

I'd say 5% overall, and maybe 15% for certain brand's reds.

with terry at PBL, it's pretty rare to even find one bad one and we go thru hundreds a month.
with CT you get some mispunched nubs on 44's sometimes, and besides a bad batch of flickery white frosted a few months ago, never really had much problems with theirs either.
Haven't tried comet or the others as the 2 I've mentioned have kept us pretty happy so far.

As he said, you have to adjust the leads on the 555s to make the connection when installing...even more on the flashers. I don't be polarity is a issue with the newer bulbs!

I order mine from China by the thousand and I would say >1%. Very rare you don't get a worker.

As mentioned above, some 555s are polarized. This means they only work "in one direction". Simply rotate the bulb (or holder) 180 degrees and try again.

Sometimes the 555s need a little tweaking. Remember your machine is likely 20 years old and the bulb holders are the same. Usually a quick rub of the holder contacts and the PCB board with fine 400 grit paper will do the trick.

rd

Outright duds: 1 in over 700 lamps ordered in the last 20 months from 4 suppliers in various types and colors.

Other failures, EASILY fixable if you can solder
- 1 where they didn't solder the center wire in the tip of a bayonet. VERY easy fix
- 2 where the wedge leads were broken on opening. Wedges are easy to fix, bend back, pull out remaining one, solder broken one back to resistor or base
- around 10 bayonets or wedges that broke after insertion and removal more than once, again quick fix on wedges, or a bit more work on a bayonet
- around 50 bayonets with head detaching from base, a bit of superglue fixes.

As others posted, are you sure (if you are on wedges) that you don't have the cheap non-polarized bulbs? Rotate and try again if that's the case. Also you need to bend out the wedge wires from the center since they're so thin vs the double sided double loop that incandescents have with much more contact area.

Use your finger nail to push the little leads to the outside edge of the bulb base. Hard to describe, but I do this on every wedge base I use and failure rate is less than 1 in 100.