Any Bally experts out there? I have some voltage questions 1978 Playboy

[jbshocks]

I hope someone can help me out a little.  I have a 1978 Bally Playboy pinball.  I bought it about 2 months ago in bad shape.  I have cleaned, touched up and clear coated the play field.  I have repaired the corroded mpu and done most of the upgrades to the boards found on http://www.pinballisnotdead.com/pinrepair/www.pinrepair.com/bally/index1.htm#minimum  On the transformer I did all but the bigger bridge rectifiers.  On the MPU and solenoid driver boards I did all include change the c23 ripple cap.  I did the initial start up voltage tests with only the transformer hooked up and everything was in spec.  I then did the test where they have you hook up the other connectors but remove J1 J2 and J5 plus fuse from the   driver board.  On TP4 I get 256 V and on TP2 I get 196.  This is where I am concerned, TP2 they say should be 160-190 or you could blow the score boards.  Then they say to check TP4 and see if it is close and if so there is a problem in the high voltage area of the board.  Is 196 V close enough or is there some thing wrong? 

I do have more wrong that I will need to dig into which is that F4 and F5 blew out while I was testing.  I replaced them with new fuses (I blew the old ones)  and only F4 blew but pin 12 of J3 on the solenoid driver board started to smoke ending tonight's testing.  I am hoping that was a loose connector.  I also realized when pulling the board that I only had 1 out of 2 grounding screws installed so I don't know if that played a part in this. 

My main question at the moment is will I blow the score boards with 196 V DC?

[Mr. Dinoman]

There is a voltage adjustment for the 190v output...There is a +/- 5volt tolerance...Attached is the schematic
Jimmy

[jbshocks]

cool Thanks,  I never noticed that adjustment.  Should it be dialed close to the 190v or somewhere between 160 and 190?   I read that pin 12 of j3 commonly burns, do you know why?  If I change the pins and connector am I likely to fix it or should I be looking for another issue?  What I have been reading is that F4 is common to blow from a short on the 43 volt line so I guess I have to dig on that as well.

[Mr. Dinoman]

If you lower the voltage slightly less than 190vdc, it will prolong the life of the displays...As far as the pins burning, replace or bypass them and/or use LED bulbs...If you are using #44 bulbs consider using #47- there not as bright and draw less power...If you plan on keeping the Playboy, I recommend the LED bulb kit...Make the game look really cool!...Hope all this helps...
Jimmy

[poppo]

FYI, if your displays are worn out or have missing segments etc., you may want to consider replacing them with LED displays. They are plug and play and you don't use the 190V at all.

[Mr. Dinoman]

they are made by Pinscore and come in reg. color (orange), blue, red and green...

http://www.marcospecialties.com/pinball-parts/PS-2518-A

Jimmy

[jbshocks]

thanks for the tip.  I hope mine are good as these are pricey little jewels.

[poppo]

thanks for the tip.  I hope mine are good as these are pricey little jewels.

If you do decide to go that route, you may want to consider getting 7 digit displays and using a modified ROM that let's you go over 1M points. That's what I did with my Space Invaders. IMO it's too easy to get 1M points and then it just rolls over.

The modifed ROM can be found here.
http://www.ipdb.org/machine.cgi?gid=1823

Instructions for the hardware mod are here. You only need one for all of the displays. It's not that hard to do
http://www.pinball4you.ch/okaegi/pro_d7.html

Here is mine.

[jbshocks]

I decided that I would get POd to rebuild that burn connector and burn it again so I hard wired pin 12 to keep testing and it no longer gets hot so I don't think I am worried about that for now.   I was able to dial down the 190 volt line.  I have it ate about 180.  

The trouble I am chasing now is F5.  I can plug in the play field all day long and the lights work and fuse won't blow.  If I plug in the top box it will not blow right away but it will blow after about 1 minute.  If I don't give it a full minute before turning it off, it won't blow but the fuse will be very warm.  I have only J1, 2 and 3 plugged in on transformer and all other boards unplugged.  Ground strap is not touching anything and I don't  see an obvious problem.  I still have the score boards plugged in but I assume they don't use the GI circuit.  What should I be looking for to be shorted?  Do the sockets short out? I took all the back light bulbs out and still have the trouble.  I let it blow the fuse and felt around for a warm spot but nothing.  Is there anything common?

[Mr. Dinoman]

If you take all the bulbs out of the backglass check for short in wiring with Ohm meter...Double check that you are using the correct bulbs in each spot...

[poppo]

I assume the lamps are lighting until the fuse blows?  You are using a 20A fuse correct?

Just a guess, but check your lamps sockets on the the coin door. I think they get fed from the top box G.I. 

[jbshocks]

the lamps do light until it blows.  Coin door will light with play field and top box unplugged so that doesn't seem to be it.  I ohmed out the back lighting with no bulbs and shows open. 

[poppo]

Ok. And you are using a 20A fuse? Might try putting the bulbs in one at a time. Also as Mr. Dinoman asked, are you sure they are all the right bulbs?   
 

[jbshocks]

I am using 20 amp fuse and I have no bulbs in and it blows.  I am going to re check my pin out on J# and see if maybe I somehow have something off

[Mr. Dinoman]

Poppo is correct, you need a 20a fuse...All lamps are #44 (but like I said earlier, you might want to us #47)...Did you repair the burning pins...If you did not, they are probably creating a high resistance and therefor drawing more current then the 20amps....You need to fix that problem first...You can also disconnect the GI plug that feed the playfield and see if that stops blowing the fuse also and only plug in the backbox....

[poppo]

Might have a short to another wire. Could be a pain to track down. Might have to follow J3 Pins 10&11 by hand.

[poppo]

Did you repair the burning pins...If you did not, they are probably creating a high resistance and therefor drawing more current then the 20amps....

Actually more resistance would result in less current. I=E/R 

[Mr. Dinoman]

Here is a better definition of what I meant:

"The GI connectors can get hot and fail. This happens because the Molex connectors don't always have enough surface area to handle the GI power requirements. The heat from the connector will cause the solder joints to fatigue which causes resistance (and more heat). The connector pins get so hot they soften the solder. All this causes more resistance, which causes more heat. It doesn't end till the board burns, the fuse heat fatigues and fails, or the connectors pins fall out (or burn!), and open the circuit."

[poppo]

True, the connectors can get hot and will burn etc.. This will result in higher resistance at the connector and would cause things like the lamps not to light. However it would not cause the fuse to blow. The only way for a fuse to blow is to have too much current flowing though it. And more current means less resistance (i.e. a short).

Now, if the board is burnt, it can cause a carbon short to an adjacent pin that may cause too much current to flow. But a burnt connector alone won't cause the fuse to blow.

[poppo]

Something else to try is unplug eveything from your lamp driver board in the top box. I know that uses a different supply, but it may help to narrow down if something in the GI lighting is shorting to one of the switched lamps (or if somone wired one wrong).

[jbshocks]

Thanks guys for the tips.  I changed all J3 board pins  on the power supply and connectors on 11 before this all started.  I also changed that connector housing over.  I swear I did it one wire at a time.  Turns out wire 10 and 8 (both orange were swapped.)  This had the GI circuit powering the 5 volt VR circuit blowing the fuse.  I put a new connector on the large orange for pin 10 as well.  My blown GI fuse issue seems to be solved but now I have a problem with the 5 volt VR that I sadly seemed to have caused.  

[poppo]

It happens. Glad you got that part fixed. In case you don't already know, here is a good source of parts, including the 5V regulator kit.

http://bigdaddy-enterprises.com/repairkits/bally_kits.htm

[Mr. Dinoman]

Glad to hear it to....FYI If a #44 bulb has a wattage of 1.575 and is supposed to run on 6.3 volts than the bulb would be drawing .25amps...Now, if the voltage was dropped because of a burned pin to lets say to 3.33 volts-the current draw is now .50amp therefor increasing the current draw and blowing the fuse...I have had this happen on some of my pins...Replacing the burned pins solved my problems...Also as a electrician, It has happened that a loose wire at a breaker can cause the breaker to heat up and trip...
Just sharing experiences...

[jbshocks]

The little c29 cap is clearly shot on the driver board.  What are the odds that the VR has lived?  Do you figure my new C23 is shot from the AC as well?  I am wondering if I need the entire 5V kit or run to the shack tomorrow for the small caps.  What do you think?  I have changed to the #47 bulbs.  I would like LED but will have to wait and see what I have in this thing once it is going.

[poppo]

Glad to hear it to....FYI If a #44 bulb has a wattage of 1.575 and is supposed to run on 6.3 volts than the bulb would be drawing .25amps...Now, if the voltage was dropped because of a burned pin to lets say to 3.33 volts-the current draw is now .50amp therefor increasing the current draw and blowing the fuse...

Sorry, bit you still have that backward. The lamp resistance will remain constant for all practical purposes. Decreasing the voltage will decrease the current. Wattage is voltage x current, so the wattage will not stay at 1.575w if the voltage changes. Wattage ratings are at the specified supply voltage.

It's simple ohms law. I=E/R  Assume the bulb has a 10 ohm resistance. At 6.3v the current would be 6.3/10 = .63 amps. Reduce the voltage to 3.3 volts and the current is 3.3/10 = .33 amps. You simply can not blow a fuse by increasing the resistance, only by decreasing it.

FWIW, I was an electronics instructor for quite a few years.