I picked up a LW3 with a few problem I have been working through. One that has me stumped is that the topper beacon spins continuously from the second it's powered on. I changed Q25, which I believe controls the beacon, because it tested bad. I thought that would fix it but it didn't. The pre-driver tests fine, so I am not sure where to go from here. I guess it could be a TTL chip or PIA? Anybody have this problem before or know how to fix it?

Also, it had a pop bumper stuck on and melted the coil. I replaced the coil and the Q9 and the pre-driver which is a 2N4401. I did not have a 2N4401 so I used a 2N2222A because I read somewhere they were compatible. Well the PB coil does not lock on now but it will not fire at all. Do you think the sub transistor I used would be the problem?

Thanks.

Wow! I thought I checked that they were both EBC. I guess I read it wrong. I will try swapping that out with the right part and try again. Thanks guys. I'll report back when I try these suggestions.

Update: I replaced the wrong transistor with the correct one and it did not make any difference. I also changed the pre-driver on the beacon just to make sure and it did not make any difference either. A friend helped me track it down and now it looks like a logic issue. I am going to swap out one of the 7402 chips and see if that fixes the pop bumper. I am not sure if that chip has anything to do with the beacon though.

Best I can tell, the chip is made up of 4 NOR gates and each one controls a coil. So it's possible that just one gate is bad and the other 3 are fine, I think.

Well, the new 7402 chip fixed the non firing PB. Still not sure about the beacon yet though.