williams Pharaoh reset problems

[flipping mad]

I'm having an issue when I use all flippers at one time or when under heavy ball loads, I've got a new diodes rottendog boards (power and CPU) new bridge rectifiers and it still resets.
There is a power drop when I use the digital multi meter on the power board connector (all new molex connectors too)
I'm running out of ideas. Could it be the transformer? If so how can I check it safely HELP!

[Strangeways]

I'd be looking at the power supply, but that has already been replaced. I would assume it is ok. I'd be looking at the connectors from the machine to the power supply board.

It won't be the transformer. It will be something more simple. It can't be the flipper coils - unless one is faulty and there is an over rated fuse. If a flipper coil was suspect, it would blow the fuse. If the fuse is over rated, it would cause issues further upstream - in the boards.

[flipping mad]

Thanks mate, I'll change all the connectors ( look a bit corroded) and go form there
Funny I thought I'd done the ones under the playfield but turns out I'd missed them.
Hope that's it because the rest of the resto has been a breeze

Cheers

[beaky]

even though the power supply is new it still could be the problem (i have had to repair that many new rotten dog power supplies its getting beyond a joke).
I would be checking the connectors as strangeways suggested.
did you replace the connectors for J1 and J2 for the power supply? (12pin and 6 pin connectors)
do you still have the original power supply?

[flipping mad]

Yeah mate j1 and j2 have been changed and I've got an original power supply to try here and it's the same problem. I'm going to change all the connectors over the next few weeks and see if that fixes her (I think that's the problem) Ohhh and I've got the original CPU too I noticed you do board repairs and are in the area. Can I get in touch with you to do some work?

[beaky]

Yeah mate j1 and j2 have been changed and I've got an original power supply to try here and it's the same problem. I'm going to change all the connectors over the next few weeks and see if that fixes her (I think that's the problem) Ohhh and I've got the original CPU too I noticed you do board repairs and are in the area. Can I get in touch with you to do some work?

not a problem, message sent

[beaky]

i went over and did a test today on the rotten dog power supply and after fixing a connector problem the reset took longer to happen, instead of happening once all 4 flippers were activated it would take about 5 to 10 seconds to reset (depending on how many times the flippers were pressed)
I put a meter on the +5 at the power supp and with each time the flippers were pressed (at around 1 second between each press) the voltage would drop .03 of a volt (5v, 4.97, 4.94, 4.91 and so on) until the machine would reset.

I fitted the original P/S which has already had its caps replaced and no more resetting, no more voltage drop so i removed the power supply and replaced the headers related to the +5v with new
headers and also the connector for the AC input

I was told that after the rotten dog P/S was fitted the connector for the +5 to the mpu board was replaced. (this would more than likely be the cause of the original reset problem)

after getting the machine to run stable i re fitted the rotten dog power supply and the resetting returned

long story cut short another dodgy rotten dog power supply.
it may be cheaper to buy a new power supply buy it is not always the best thing to do.

[dealers choice]

Great work once again Andrew. from what ive heard still no probs from the boards You repaired  ^^^on the machine I had. 

[beaky]

Great work once again Andrew. from what ive heard still no probs from the boards You repaired  ^^^on the machine I had. 

thanks and good to hear,
i try my hardest to make the boards run for another 20 years.

[Marty Machine]

I put a meter on the +5 at the power supp and with each time the flippers were pressed (at around 1 second between each press) the voltage would drop .03 of a volt (5v, 4.97, 4.94, 4.91 and so on) until the machine would reset.

Hmmmm, the accumulative decrease in volts looks like the main filter cap(s?) is dodgy and not recovering/charging quick enough to feed the regulation circuitry....
I haven't had the pleasure? of working on a dog board, so i'm not familiar with whats going on around their regulation design.....

just my 2cents ;-)
MM

[beaky]

I put a meter on the +5 at the power supp and with each time the flippers were pressed (at around 1 second between each press) the voltage would drop .03 of a volt (5v, 4.97, 4.94, 4.91 and so on) until the machine would reset.

Hmmmm, the accumulative decrease in volts looks like the main filter cap(s?) is dodgy and not recovering/charging quick enough to feed the regulation circuitry....
I haven't had the pleasure? of working on a dog board, so i'm not familiar with whats going on around their regulation design.....

just my 2cents ;-)
MM

That does make sense marty
the weird thing was u stop pressing the flipper buttons the voltage would not go up.
The only time it would recover is when the mpu board went into reset.
I will let you know what the problem was when I sort it out:

[Marty Machine]

the weird thing was u stop pressing the flipper buttons the voltage would not go up.
The only time it would recover is when the mpu board went into reset.

Hmmm, that's even worse ;-( what a crappy fault!!

[flipping mad]

  Beaky your a pinball Yoda, and was a pleasure having you over and I'm amazed at the amount you know mate.
Your welcome here anytime and hope you liked Pharaoh and my other toys
Just goes to show that the boys at williams had it right all those years ago and that it's better to rebuild an old board and stay true than go the new.
Like you said the name suits them damn ROTTENDOG!

[beaky]

Beaky your a pinball Yoda, and was a pleasure having you over and I'm amazed at the amount you know mate.
Your welcome here anytime and hope you liked Pharaoh and my other toys
Just goes to show that the boys at williams had it right all those years ago and that it's better to rebuild an old board and stay true than go the new.
Like you said the name suits them damn ROTTENDOG!

thanks mate.
i really enjoyed having a game on it.
that cabinet looks absolutely fantastic.
it was really strange to have a WPC style fault (press both flippers and then  have a reset) on a system 7 machine.
I have just started the diagnoses of you original system 7 mpu and driver boards tonight. there is a problem on the MPU board, I haven't narrowed it down yet, Lets hope it's not some ancient Egyptian curse  . 

[Freiherr]

Beaky your a pinball Yoda, and was a pleasure having you over and I'm amazed at the amount you know mate.
Your welcome here anytime and hope you liked Pharaoh and my other toys
Just goes to show that the boys at williams had it right all those years ago and that it's better to rebuild an old board and stay true than go the new.
Like you said the name suits them damn ROTTENDOG!

Lets hope it's not some ancient Egyptian curse  . 

OMG don't say that, there may be others.