| Arcade Collecting > Restorations & repair |
| Atari Centipede Cocktail table game has no power |
| << < (33/60) > >> |
| jennifer:
White to green, good, anything to black, bad...From what your saying I think, (and from looking at your volt chart) is everything is good until you hook up the interlock then the problem begins (but checked out as good)...Well That would suggest it is either wired incorrectly or something downstream is tripping those fuses...keep the board out of the loop until the end and voltages can be verified...So go back to the your "brick" it's not popping fuses, and aparently checks out fine with no load... This is your jumping off point, whatever you plug into it causes the trouble. |
| PL1:
--- Quote from: vapuser on February 16, 2020, 10:43:15 am ---Check out reply 32 for a pic of the underside of the brick. That will show the Bridge rectifier and the big blue cap. --- End quote --- Based on the schematic Mike posted, the cocktail should have a 2 diode full-wave rectifier, not the 4 diode bridge rectifier shown in the upright schematic. The two types of rectifiers perform similar functions, but are wired to the transformer and C1 differently. The full-wave rectifier applies a positive to the positive terminal of C1 from whichever diode is forward biased with the negative terminal of C1 tied to the center tap. - Only one half of the winding is used at a time. - Orange (ends) to violet (center) = 1/2 of orange to orange - Think "top pushed up and bottom stays in the middle". A bridge rectifier applies a positive to to the positive terminal of C1 from whichever diode on the top half is forward biased and applies a negative to the negative terminal of C1 from whichever diode on the bottom half is forward biased. - Both halves of the winding are used at the same time. - Think "top pushed up and bottom pushed down". Correct me if I'm wrong, but it seems like the orange to orange windings for the transformers in the cocktail and upright would be different values for the different types of rectifiers to output the same voltage. :dunno Scott |
| jennifer:
I think you may have something there,Effectively a half wave rectification, that would explain why it is ok, until it has a load...Clever PL1😉 |
| PL1:
Thanks, Jennifer. :cheers: I agree about the "ok, until it has a load" part of your comment, but disagree about the "Effectively a half wave rectification" part. A one diode half-wave rectifier would only use the positive part of the waveform -- but that's not the problem here. In this case, I'm referring to the transformer difference between the two types of rectifiers used to generate the same voltage (Vm) at the load. (RL) Full-wave rectifier - End tap to end tap (A to B) = 2 * Vm - Voltage at load = Vm. Bridge rectifier - End tap to end tap (A to B) = Vm - Voltage at load = Vm. If you connect points A and B of the bridge rectifier circuit to points A and B of the full-wave circuit's transformer, you get twice the voltage (2 * Vm) applied to the load. More details at https://www.elprocus.com/full-wave-bridge-rectifier-versus-center-tapped-full-wave-rectifier/. Scott |
| Mike A:
I have my cab all opened up. If you need pics of anything just let me know. I can leave the cab disassembled until the end of the month. |
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