Time Machine
Data East, 1988I have been trying to troubleshoot my Time Machine ball trough. I am getting good voltage at the coil and the transistor is testing in spec, but the machine doesn't fire the coil hard enough to launch the ball. I have swapped the coil for a known good one and the behavior continues. Is it possible to have a transistor test in spec and still have issues? Is there an IC that isn't clocking the right strength to the coil? Spit balling ideas at this point. Thx
The logic reply would be to test the physical items in the ball trough assembly. I mean - if the electronics test out fine then you would assume that it's a physical thing that is making the launcher week.
I don't know how the assembly is put together on Time Machine but it should include spring, sleeve, coil stop, coil mount and stuff like that. Have you checked that the physical components that make ud the ball trough can move unrestricted?
Another question - when you say that the transistor test in spec - how did you measure that? In board testing or did you take the transistor out? What did you test for and how could be interesting to know.
Well, to give some more background. I tested the transistor on the board and didn't remove it. The symptom began as a slightly weak coil, and when I went to replace it, I put another coil in and didn't realize that the diode was reversed. Whatever that diode was supposed to protect might have been damaged. It has a fresh coil and sleeve and seems to travel freely. I am confused, because I am still getting 40V at the coil and it seems like it is a weak pulse.
Ok - if the diode was reversed I would start by looking at the transistor.
Doing on board testing is not completely reliable as other components might affect how it test out. If you are ok with soldering I would take it out and test it again. And if you have a known working spare you might put that in instead. If you do not have a spare you could consider swapping the transistor with one of the others you might have on the board!
A faulty transistor could also explain the weak pulse. I'm guessing the transistor you are talking about is acting as a switch for the 40v to the coil?
Just swapped the Tip122 and it was good, no change in symptoms. Ken, I will try the joint connectors next.
Problem solved: Turns out that Time Machine uses the trough switch to act like an EOS for this coil. Because the switch was set too sensitive, it was cutting the power to the coil before the ball could make it into the shooter lane. So, an adjustment to the switch was all that was needed. Thanks for all the replies.
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Maple Grove, MN
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