Hi!

I am going to measure the volts coming out of the transformer in my BoP. I first thought that i would just measure like "normal". One DMM "pin" at one wire and the other DMM pin at ground. For example the ground strap in the cab. However, when reading some more I have seen posts here and there saying that such an approach would not give any good results. Instead one should measure "across the transformer".

Question is, what does that mean and how do I do it? Is there some special ground on the transformer or what?

Andy

Ok.. I am doing the measuring to see if the transformer is OK and if the harness is ok. So I would like to rule out the wires going up to the connectors at the board. Just measure the transformer "clean" so to speak. The reason is that i have not been able to find any good volts at the J101 and J102 connectors...

So as you wrote, the transformer has its own connector where the wires goes from up to the back box. I was planing to measure at that connector (disconnect it and measure in it).

And as I understand it (from your answer) I should measure between two wires down there (like i would at the connector in the bb). For example there are two red wires from this transformer connector and two wires that are blue/white etc. Would it be a good idea to measure with one DMM pin at one red wire and the other at the other red wire? And then repeat the step for the other wires, for example one pin at one blue/white and the other pin at the other blue/white and so on? =)

Of course i will check the schematics before that to see it the blue/whites are the same circuit, the two reds another same circuit etc. But in theory, is that correct?

Andy

Thanks a lot for clearifying this!

I will do it together with an electrician who is a friend of mine. Would be unwise to try myself before i get any more knowledge and skill.

Its my first pin restoration project so i thought id do the measuring from start at the wall socket, to finish, power driver board output connectors to pin point the problem. The machine is not booting as for now and according to the leds and test points on the power driver board it lacks +5VDC.

After i know if the transformer and wires up to the board are ok i can continue searching for the problem on the board. Probably the same as whith reset issues so with some reading in the guides at for example pinwiki it should be able able to fix! =)

Thanks a lot!

Noahs_Arcade:
Thats interesting.. when we measured at the J101 and J102 connectors we found that the voltage was indeed half of what was expected! But we measured from one pin to GROUND (strap in BB) then. Maybe that explains it!

Will do it again across the wires and see what happens!

/ Andy

Allright! I Will try measuring tomorrow then ill report back! The AC is alternating and the DC direct... So the + and - so to speak does alternate between each wire i guess? While the DC just goes from A to B all the time. In AC there is no + and - if i remember things right. Well i might read up a bit =) anyway, ill try and see what i get tomorrow!

I will try to keep this problem in the main thread here:

http://pinside.com/pinball/forum/topic/no-power-when-powering-on-need-some-directions-to-start-in

Have a look there for the measured results!