(Topic ID: 204647)
Toledo, OH
R-4 33 ohm 5% 1W according to my manual for Volcano.
R2 1K ohm 5% 1/4 W
There is a gottlieb system 80 board club.
You should mark it as a favorite.
Pinwiki has a section on System 80 power supplies, which includes ground mods.
http://www.pinwiki.com/wiki/index.php?title=Gottlieb_System_80
Limassol
The power supply board on my Sys80b Robowar was "misbehaving" and the replacement was 60 euro.
I replaced it with a miniature switched supply pcb from ebay , that costs 5 dollar and the voltage (5 volt) is rock solid ever since !
Will provide some more info when I get home 
Charles
The problem is not in the 5 volt supply --> it's the 60V display voltage.
R4 will overheat if your system has been drawing too much current from the supply. The current limiting is supposed to shut down the voltage regulator before this happens but based on the condition of R2 - I'd say the current limiting has a problem.
If Q1 is shorted - current limiter Q2 can be *trying* to shut Q1 down but not succeeding causing an issue like what you see. Likewise a shorted Q2 can cause a similar issue but I'm leaning towards Q1.
First need to rule out what is good versus what is bad. What voltage do you get between TP3 (ground) and E3?
And what voltage do you get between TP1 and TP3? What condition is R3 in (he looks like he ran hot as well)?
R4 was a 33 ohm, 1W resistor. when replacing - I would use a 2W metal oxide or wire wound resistor (those can take the heat much better).
R2 is a 1K, 1/4W resistor. He normally does not heat up and is the reason I suspect a current limiting problem.
Q1 -- use a TIP31C, Q2 is 2N5550 or 2N5551. Get heat sink compound.
While you're at it - replace R10 with a 680 ohm, 1/2 watt resistor and update electrolytic capacitors.
This higher value R10 will cause less heat on your CR7 zener which will reduce baking on capacitor C2.
Funny I came upon this thread. I picked up a Black Hole which the previous owner claimed "was working and then started having issues and now it won't boot". One small problem with that theory, someone had done the power supply mods so I decided to verify the components they used. At R10, the mod calls for a 680 ohm 1/2W resistor when replacing CR7 (which is usually toasty). On mine, R10 was replaced with a 680,000 ohm 1/2W resistor hahaha. Pretty sure the 3 magnitude difference is a large reason why this game doesn't work 
Anyways, like the OP, I'm in the middle of doing the LED mods and cleaning up the previous work and see where that leaves me.
One of the mods is to double up the 5V and ground lines on the MPU<->solenoid interconnect. That interconnect edge connector uses flat pins. Does anyone know where to source those?
Hi Ed,
Are you going to carry the new 12 pin edge connectors that require cutting the extra slot?
Do they use the same pins at the original edge connectors ?
Is anyone working on a "header adapter " kit?
Thanks
Cliff
To add to this --
R10 can be anything from about 300 ohms to 680 ohms. Higher value = less heat but also more of a chance of transformer load current affecting the voltage (as if it really matters that much). Lower value = more heat but less of a chance of transformer load affecting the voltage. I just shoot for a happy medium and use 470.
They supposedly use a different contact.
Part number 172160-1803. Spitting image of the older 08-50-0116 bifurcated contacts which do fit the older edge connectors. The new contacts are side joined contacts in strips - an absolute royal pain in the derriere to cut apart.
Also have a sample 172159-0208 which the 8 pin version. I plan on trying the older style contacts to see if they fit but gotta find the time.
These new edge connectors may help for the smaller connectors but over 12 pins, we're SOL.
At the rate the plugs are dissappearing, I'm afraid that header adapters may become a necessity. Shudder at the thought.
Quoted from G-P-E:Shudder at the thought.
I agree.
I have looked at this and because of the spacing of the contacts on the board, careful drilling for a header will not space out regardless of the header size.
It will be hard to go to a header without it looking totally hack.
Quoted from G-P-E:The problem is not in the 5 volt supply --> it's the 60V display voltage.
R4 will overheat if your system has been drawing too much current from the supply. The current limiting is supposed to shut down the voltage regulator before this happens but based on the condition of R2 - I'd say the current limiting has a problem.
If Q1 is shorted - current limiter Q2 can be *trying* to shut Q1 down but not succeeding causing an issue like what you see. Likewise a shorted Q2 can cause a similar issue but I'm leaning towards Q1.
First need to rule out what is good versus what is bad. What voltage do you get between TP3 (ground) and E3?
And what voltage do you get between TP1 and TP3? What condition is R3 in (he looks like he ran hot as well)?
R4 was a 33 ohm, 1W resistor. when replacing - I would use a 2W metal oxide or wire wound resistor (those can take the heat much better).
R2 is a 1K, 1/4W resistor. He normally does not heat up and is the reason I suspect a current limiting problem.
Q1 -- use a TIP31C, Q2 is 2N5550 or 2N5551. Get heat sink compound.
While you're at it - replace R10 with a 680 ohm, 1/2 watt resistor and update electrolytic capacitors.
This higher value R10 will cause less heat on your CR7 zener which will reduce baking on capacitor C2.
For q1, you said tip31c, i have a tip 31. Same thing? Struggling to find a 30k resistor or a 2watt wire wound.
No -- a TIP31 won't work. Must be the "C" variant.
Without the "C" - it has a breakdown voltage of 40 volts (not good for a 60V supply). The TIP31C has a breakdown voltage of 100V.
And the resistor -- 33, not 33K. Metal oxide or wire wound - they hold up to the heat better than the carbon film that Gottlieb previously used. Metal oxides are easier to find.
I have some here:
https://www.greatplainselectronics.com/proddetail.asp?prod=RMO2-33
But I'm shut down for a few days to catch up on orders.
Can also find a Mouser equivalent.
Part number 262-33-RC or W2M33R0J.
While you're at it - replace R3 with something like a 281-12K-RC
Ya, sorry, i meant 33, not 33k. Got the board out, and its definately been worked on a lot. Bad traces everywhere. I enjoy trying to learn board repair so i may still try to fix and not replace. Thanks for all the help so far!!
3 weeks later
Quoted from amkoepfer:I ordered a new board, i have 5v,12v, my 60v is reading high, but still no 42v. Anyone have a schematic laying around? I cant figure out even which connector is the 42v wire so i can repin it.
Exactly how high is the 60V reading?
As I recall, the 42VDC is only used by the smaller ball credit display. You might want to unplug it and check your 42 volts again.
Quoted from G-P-E:Exactly how high is the 60V reading?
79-82v
Quoted from CactusJack:As I recall, the 42VDC is only used by the smaller ball credit display. You might want to unplug it and check your 42 volts again.
Ill give that a try. Im probably going to order a schematic so i can start sorting through this
North Adelaide
Thanks raff. Im starting to wonder if its in the power board or if it could be in the transformer. I dont get a lot of time to work on it, so i seem to go back over things multiple times refreshing myself every time i work on it
Quoted from amkoepfer:79-82v
This says your transformer is fine but your 60V regulator is not working.
60V +/- 10% is OK but this is way too high.
What do you measure at E1 and E2?
The 60V regulator is comprised of:
R1 -- 1.3K, 5W
CR5 (if replacing, use 1N5372B)
Q1 -- TIP31C
Plus 60V current regulation circuit:
Q2 -- 2N5550 or 2N5551
R2 -- 1/4W, 1K
R3 -- 1/2W, 12K but I recommend 1W, 12K small form factor metal oxide due to heat
R4 -- 1W, 33
When you get the 60V supply going - then worry about the 42V.
This one is easy as it is comprised of two parts:
R5 -- 1/2W, 10K
CR6 -- 1N4742A
Huh? Brand new board?
I thought we were looking at an old Gottlieb board as shown in the photo of post #1 above.
OK -- is this not a Gottlieb board? If not - whose board is this?
But - at this point, it does point to the 60V section of whatever board you are using.
LOL!
(While technically accurate - the inflammatory wording of the original post was unnecessary and deleted)
Yes, it does have a bad HV supply if you are getting about 80V out of it.
Apparently they didn't copy my thorough, under load acceptance testing.
Nah, the board will be fine with a bit of TLC.
But apparently that one failed "customer test procedures".
The HV circuit that they copied... is the one that I copied and is the same one that Gottlieb copied. But at least I went through all the calculations to verify component choices. Dry reading:
https://www.greatplainselectronics.com/Information.asp?region=143
If you got the full size board, then you got the beefed up version of the original Gottlieb design. If you got the half board then you pretty much got the exact same design (and reliability) as the original design.
This is a very popular and reliable "series pass transistor" type regulator where the entire regulator consists of three components -- series pass transistor (probably a TIP31C on their board), a voltage setting zener diode (they originally copied me and went to a 1N5372B) and a zener diode biasing resistor. Not sure what value they use for this resistor but it is often a 5W, 1.3K resistor. Can be anything from 1.3K to 1.8K. My calculations say a 1.8K is optimum value.
I doubt it is the current regulation components of this design -- if so, those are listed in post #34 above.
The thing that gets me on this is both have the same problem.
Something in your machine might be taking out the HV circuit.
Not the transformer as it is providing the correct voltage. Might try following the 42 and 60V wires through your machine and make sure it isn't shorted to something else somewhere down the line.
Since you read 0 volts on your 42VDC line, I expect the Ball/Credit display is shorted thereby drawing too much current on the 60 volt regulator and shorting one or more components (which is why you are getting too high a 60v reading now).
So, it's possible the new power supply was good until you plugged it into your game.
Hopefully, the 80v won't/didn't take out any of the UDN6118's on the larger displays!
1 week later
Reply
Wanna join the discussion? Please sign in to reply to this topic.
Hey there! Welcome to Pinside!
Donate to PinsideGreat to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, subscribe to Pinside+!
