Black Knight pin blowing fuses

[SirPeale]

Have a client with a Black Knight pin that's blowing fuses.

He claims that it's blowing fuse F3, which I'm guessing works certain solenoids (I haven't looked it up yet).  The other fuse he says:

The other fuse that keeps blowing is a fuse that is mounted on to the back of where all of the score displays are mounted. When I ran the diagnostic on the machine I think it is referring to the jet bumper malfunctioning up top.

Having not seen the machine in person (and it being a two hour trip, one way) I want to be as prepared as possible.  I'm betting at least one bad coil, but the other one has me scratching my head.

[ChadTower]

F3 is lamps.

I don't know of any fuse on the backside of the display door.  My BK does have the sys6 style power supply but I don't remember a fuse back there on any other Sys7 games I have worked on.

[SirPeale]

F3 is lamps.

That's what I thought, but he's saying all the lamps are lighting up.  Only the flippers and pop bumpers are failing.

The machine powers up and all of the lights display. However the flippers and bumpers do not respond.

I opened up the top part of the machine with all of the boards. When I set up a new game the flippers worked for a moment then the F3 fuse blew. The other fuse that keeps blowing is a fuse that is mounted on to the back of where all of the score displays are mounted. When I ran the diagnostic on the machine I think it is referring to the jet bumper malfunctioning up top.

and this is from a tech that can not get to the machine any more:

I am fairly certain one of the coils has internally melted and shorted and just needs to be replaced. The other blown fuse in the lighting circuit I don't know the cause. You can measure the coil resistance of the new coils and match it to the old ones.

If they are within a few ohms they are probably fine. They have to be un-soldered from the power circuit first, then measure the resistance. The shorted one (or more) should stick out like a sore thumb.

The other thing to check is the output of the transformer. They have a tendency to go bad after a few years (heat damage) and output higher voltages which in turn will melt the coils (and other parts). Replacements are available, just hard to find. I have replaced two machines with newer solid state power supplies instead of the transformers for the 50vDC outputs (coils) and just left the lighting and logic circuits hooked to the transformer.

Okay...rereading this the other fuse that is blowing must be related to these solenoids.  No idea why the lighting fuse would be blowing if the lights are working.

[ChadTower]

Lamps and GI are separate circuits.  Don't trust his ability to know the difference.

Those transformers are just like any other 1980 game.  A block of steel you could throw in the ocean and pull back out a year later and it still works.  It's the power supply board that develops problems, often starting with those standalone BRs.

Black Knight doesn't have 50v flippers.

This is a tough game to drive 4 hours to fix and support.  That boardset is going to be super flakey if that 40 pin hasn't been swapped.

[SirPeale]

Lamps and GI are separate circuits.  Don't trust his ability to know the difference.

Yeah, there is that. 

Those transformers are just like any other 1980 game.  A block of steel you could throw in the ocean and pull back out a year later and it still works.  It's the power supply board that develops problems, often starting with those standalone BRs.

Black Knight doesn't have 50v flippers.

This is a tough game to drive 4 hours to fix and support.  That boardset is going to be super flakey if that 40 pin hasn't been swapped.

Knowing little about this particular pin, can you expand on that?

I hate distance repairs; they're either something so simple that all my research I did beforehand doesn't apply and it's fixed in short order, or you go around and around and then find out you don't have the right parts on hand, necessitating a return trip.  I'm really trying to avoid that.  If only these machines all used the same solenoid, I'd just grab one and chance it.

[ChadTower]

Expand on which part?  If you mean the 40 pin connector, go over to Clay's guide and read up on it.  I can't explain it better than he does.  It's pretty much a 100% mandatory rehab task for reliability on any Sys3-7 game.  If you drive all the way out there, tell him you'll support his game but don't replace the 40pin interboard connector, you're going to be chasing phantom problems in that game indefinitely.

Now, given that another tech has looked at it, maybe it's already done, but 4 hours is a lot of driving if you don't know.

[SirPeale]

Yes, I was talking about the 40 pin connector.  I'll look it up.  You said Clay - are those docs on Marvin's site?

[ChadTower]

Yes, I was talking about the 40 pin connector.  I'll look it up.  You said Clay - are those docs on Marvin's site?

Yep, that's the author's name.

http://www.pinrepair.com/sys37/index1.htm#interconnect

I didn't think I could get to that site from here but today I can.  There's the url.   

[SirPeale]

Yup, I found it.  Looks like an easy swap, assuming the solder is still good.  Waiting to hear back from the guy.

Heck, it might be easier to take the whole machine back to the shop and do the work there.

[ChadTower]

Easy swap, time consuming if you are charging by the hour and cannot point to a specific need to replace it.  And it's a specialized part, definitely not one you have on hand otherwise.  GPE is a good source.

You often also run into battery corrosion on the left side of that connector.  That's where the nvram/settings/audit circuit is and that can mess up the solder as you mentioned. 

[ChadTower]

If it were a local machine that would be reasonable to try.  Odds are what is going to happen here is it works fairly well now because it's all seized in place.  He is going to have to pull the driver board to make those repairs.  That is going to have a very unpredictable effect on that interconnect.  It might be fine, it might loosen crap up that goes flaky 20 boots from now, or it might just drop a contact or two while he pulls on it.  The problem here is that he's 2 hours away from the thing.

That stupid thing was designed to be modular but they put the system bus on a connector with a rated life of like 5 cycles - and it is 30 years old.   

[SirPeale]

We're still trying to come up with some data via emails.  One thing I'd like to know: how many different types of solenoids are on this beast? 

And I'm still trying to get out of him which other fuse blew.

[shardian]

Go look at it and check for the basic stuff. Give it 1-2 hours max if you don't find the issue, then tell the guy you'll have to take it back with you and it will cost him. Charge for 2 hours labor regardless if it is a 5 minute fix - you've already invested that much + more in pointless research without solid info. Make him aware of all this from the get-go. That is really the only solution that keeps your tenders out of the vice.

[SirPeale]

Offer him $150 for it as-is and tell him you're too busy to look at it otherwise.

Seriously.

Black Knight is a maintenance nightmare.  He'll break it 48 hours after you have it repaired.

Not gonna happen; apparently he's the original owner and it has great value to him.

[SirPeale]

That's why I'm trying to reduce that headache. 

I finally got some snaps of the fuses in question. 

[ChadTower]

This is a pic from my resto thread - there appears to be something white in that same spot but if there is a fuse there I have never had reason to look at it.  I'll look tonight and see where that white/yellow is going but it looks like it's going to flashers.

[shardian]

That fuse is in-line with what I assume are the flashers. Part of it terminates at a single socket next to the circuit board. Extra note: seeing electrical tape in the wiring in that area makes me cringe a bit.

That fuse 2nd from left is toast - is that the F3 fuse?

[ChadTower]

That's F2 - the solenoid fuse.

WOW this a nice schematic...

[SirPeale]

That IS a nice schematic.  Thanks, Chad.  According to that, it is indeed the F2 fuse that's blowing, not the F3.

He's got some spare parts as well - several solenoids.  I just found this out.  Photo attached.

[shardian]

You're welcome good sir. I've seen that black, bubbled but intact bad fuse twice on pins, once on a vid.

It appears the fix will be easy now....tell him you charge half-price if you can just guide him over the phone. 

[ChadTower]

And tell him to stop drinking weird colored melted butter.   

[SirPeale]

Finally drove up and got to check this beast out.

I'd brought a "lamp fuse" with me to help me troubleshoot.  As soon as I plugged it in it started glowing, indicating a short.  None of the solenoids showed any sign of a problem. 

Disconnected J11, light went off.  So I started unsoldering wires from the solenoids one by one from that connector until the light went off.  Then started tacking them on again.  But suddenly, the light went back on!  I was thinking I had two bad solenoids (pretty rare) but thought better of it and checked out the board.

Battery damage!  Not a lot, but enough to screw with the board.  I brought them both back with me, and I'll replace the 40 pin and repair the damage.

Anyone in the 413 have a pin of this vintage I can test repaired boards in?  I don't want to drive three hours to find out I missed something.

[ChadTower]

Three hours in which direction?  If it's this way you can drop them in my BK.

[SirPeale]

Northern VT, up near Sugarbush.

[ChadTower]

Eh crap.  Well let me know if you're in this area any time soon for other reasons before you give them back, I guess.

[SirPeale]

It's green!

[GPE]

It's green!

Common occurance when it gets wet at one time or another... board washed or even high humidity.

Ed

[SirPeale]

It's green!

Common occurance when it gets wet at one time or another... board washed or even high humidity.

Ed

Humidity would not surprise me, it was stored in a basement for a number of years.

[lilshawn]

that would definitely do it! you probably have a hundred ohms of resistance there boy!

[SirPeale]

that would definitely do it! you probably have a hundred ohms of resistance there boy!

Yes, but this relay isn't what's blowing the solenoid fuses.  It's either a flipper replay (separate circuit) or lights.

[lilshawn]

your "green" relay is the main power for the solenoids. if the contacts are corroded, there will be a great increase of resistance... the load on the fuse will be huge... enough to blow it.

flippers have it's own separate system... your not having issues with the flippers so there is nothing there to worry about.

GI has it's own fuse on a block (just below)...unless it's blowing there is no problems there either.

check VR1 next to f2 (should read very low ohms) if it's toast it will read a short (designed that way).....The varistor is a one-time surge suppressor. When a power surge or voltage spike is sensed, the varistor's resistance rapidly decreases, creating an instant short path for the over-voltage. Because the varistor creates a short circuit, the varistor and the line fuse are damaged in the process.

also you might as well check c13 too as well since it's the filter cap for the coils

so unless you have a fried coil someplace (something that reads less than 2.5 ohms is suspect)

assuming the above are all fine...the only thing left is the relay

[SirPeale]

I must have misread - I thought there were two relays, one for lights and one for flippers.  I admit I only breezed thru what I was reading and haven't returned back to it.

[SirPeale]

Where can I find the driver transistors for the driver board?  Mouser doesn't carry them, nor GPE.  8977 or 8052 or 8039, which?

[lilshawn]

Give www.nteinc.com a try, they have a cross reference there on the site. It's a common parts replacement that is stocked at most local shops...you may be able to find a sustitute locally.
 I would do it for you, but their site doesn't work very well with my mobile phone

[SirPeale]

I was trying to stick with OEM.  NTE stuff is usually pretty highly priced.  But I did find it - NTE261.  Even states "Williams" right in their database.

[lilshawn]

sometimes you just gotta go with what you can find... on the first version main power board, the original style SDS201/SDS202 transistors at Q1/Q3 are no longer available in any flavor or form from anybody anywhere. These two transistors must be replaced with the newer MJE15030/MJE15031 transistors. BUT the MJE transistors had a different pinout than the original SDS transistors, so they must be installed differently on the board!! this was changed on later boards to fit the standard BCE pinout

SDS trans: E B C
MJE trans: B C E

B=base
C=collector
E=emitter

the fix looks stupid, but you gotta do what you gotta do...

ALSO

If any of these coils has a bad diode, this can almost instantly kill its associated driver transistor! The coil diode prevents a coil's collapsing voltage from "backwashing" to the driver board, damaging the driver transistor.

Since you spent the time to test/replace the bad driver board transistors, (you did didn't you??) it only makes sense to also check for bad coil diodes. Since these 1N4004 diodes are mounted right to the coils under the playfield, vibration can crack or damage them.

[SirPeale]

Since you spent the time to test/replace the bad driver board transistors, (you did didn't you??) it only makes sense to also check for bad coil diodes. Since these 1N4004 diodes are mounted right to the coils under the playfield, vibration can crack or damage them.

I tested them on location, but was in a hurry to get out of there that day so have lost track of which ones are bad.  Shouldn't be hard to track down.

The coil diodes are fine, and yes, I know enough to test them.   

[SirPeale]

Gah...help me out here.  I'm trying to ID the drivers on the driver board. 

8977 is easy...crosses to an NTE266, which also crosses to a TIP120.

What about a 9410?

[SirPeale]

According to the schematic, they're ALL TIP120 transistors.

[lilshawn]

 

yeah, them guys can never make up their minds....

The most commonly used transistor on the driver board is the TIP120 (along with its 2N4401 pre-driver transistor). It is responsible for driving all the solenoids. Also used is the TIP42, for the Lamp matrix column drives. The 2N6122 (TIP41) transistor is used for the Lamp matrix row drives, and the small 2N6427 transistor is used for overcurrent protection in the lamp matrix. There are some 2N5060 Silicon Controlled Rectifiers (SCRs) used too.

[SirPeale]

I'm trying to wrap this up. Before I embark on a two-hour one-way drive (and back, of course) I want to make sure my bases are covered here.

I've replaced the 40 pin connector on the driver board.  I've cleaned up the battery damage.  And I've replaced the relay.

I've got replacement transistors to swap out on-location (because I stoopidly did not mark down which solenoids were reading as bad on location).

My concern is this: the flippers were working, but the special solenoids were not.  That means (I assume) that they're not getting power.

I've been going over the schematic so I can include any possible parts along with me for my trip.   What should I bring so I can check stuff off?

This is the last long-distance repair like this I do without bringing back the machine; I would have had it done by now if I could take those measurements as I'm doing things.

[HHaase]

Just a few extra thoughts........

There are a lot of scattered solenoids that you might overlook at first,  which are unique to older machines.
Double check the solenoids for the coin door lockout, it's right next to the lock tumblers on the inside of the coin door, and got the bell on the inside of the cabinet,  left sidewall about half way back.  Most people don't even realize they are there and never check them.

The good thing is that it looks like you're dealing with a system-6 power supply, which avoids all the GI issues of a system 7. 

For the solenoid transistors,  use TIP102's instead of the TIP120's, they're more robust.
Then you have the 7408 IC chips, I assume you put these on sockets already?   Don't use 74LS08's, apparently they don't deal with the load well, but you can use 74F08's.

Definitely bring up some 9pin .156 molex connectors, at least 4 preferably six, and swap the connectors for the solenoids, specials, and possibly the lamps as well.  Use trifurcon pins if you have them.  The IDC connectors cause all sorts of havoc long term, what a pain in the ass they can be.  Inspect the board for these connectors as well, look for cracked solder joints,  if you already have the driver board you might want to consider swapping the headers while you still can. 

Now that I've had my own Black Knight for a few weeks, and have really started diving into how the board works, I'm getting a good handle on what can cause what.  It's simpler than it looks, just a lot of the same stuff repeated a number of times, both on the board and the playfield.

I'm surprise nobody threw this link out yet
http://www.pinrepair.com/
It REALLY covers the system 7's fantastically. 

-Hans

[SirPeale]

I already figured out which two solenoids were "causing a problem" and disconnected them.  I don't think it's the solenoids themselves, but their associated drivers.  Thank you, battery damage.

Where does the voltage for the relay come from?

[HHaase]

Where does the voltage for the relay come from?

Tracing backward from the relay on the driver board it goes through......
Q13 (2n4401), then IC8 (7402), IC9(7402) and IC7(7408).

IC8 also handles special solenoid's 2, 3, and 4's drive.
IC9 gets it's hands into essentially all the special solenoids one way or another.

-Hans

[SirPeale]

Revisting this finally.

Was there on Tuesday.  Figured out which drivers were bad, replaced them, popped the boards in the machine...presto...working machine.

Well...working-ish.  Lots of switches out of sorts and needed adjusting.  But when I left it was fully working.

Told the guy to play it play it play it PLAY IT.  He played it all that day, and the next.

Turned it on the next day, machine lights up but won't start a game.

He's stating that in the photo above, the leftmost fuse is blown - what fuse is that?  I don't have Acrobat on this machine, otherwise I would have looked at the schematic Chad posted above.

[HHaase]

Leftmost fuse on sys6 power supply is power to the flippers.  Shouldn't keep it from starting a game, would definitely keep the game from being playable though.  Might find the next fuse bad too,  and you may want to look at replacing the backbox rectifier for the solenoids.

Right now though I'm only running on 1 hour sleep since noon yesterday, so I'm just too tired to take a serious look at the problem right now while also chasing the baby.  Will come back with more ideas after I've had some rest and have my skull CPU running at full speed.

-Hans

[lilshawn]

Turned it on the next day, machine lights up but won't start a game.

you'd be surprised what pressing down the main CPU chip will do. also give the mainboard connectors a re-seat.

[SirPeale]

Turned it on the next day, machine lights up but won't start a game.

you'd be surprised what pressing down the main CPU chip will do. also give the mainboard connectors a re-seat.

All that was done already.  Replaced the connectors, reseated all socketed chips...

My guess?  The solenoid fuse is also bad, but "looks" good.  The guy doesn't have a meter to test the fuses, so that's out. 

What's the rating on the flipper fuse?  The guy states it only says "32V" and "ACC15".  ACC is the fuse type, but I don't see that being a 15A fuse.

[lilshawn]

Power Supply Fuses:
F1 = Score display 90 volts AC, .25 amp Slow Blow.
F2 = Solenoids 28 volts DC, 2.5 amp Slow Blow.
F3 = Lamp matrix 18 volts DC, 8 amp Fast Blow.
F4 = Flippers 28 volts DC, 10 amp (2 flippers) or 15 amp (3 or 4 flippers) Fast Blow
F5 = 9.3 volts AC (input for +5 volts), 7 amp Slow Blow.
F6 = 9.3 volts AC (input for +5 volts), 7 amp Slow Blow.
F7 = General Illumination for pinballs, 6.3 volts AC, 20 amp Fast Blow.

Sound Board Fuses:

F1 = 9.3 volts AC, 4 amp Slow Blow.
F2 = 9.3 volts AC, 4 amp Slow Blow.

[HHaase]

This is an earlier machine, with the System 6 power supply in it, so it's got a different fuse layout.
F4 is the flipper fuse, all the way to the left, 15amp slow blow.
F2 is the next one in, for the solenoids, 2.5amp slow blow.

If it's just the flipper fuse blowing, do the regular tests of the coil resistance, check the EOS switches.   Don't forget to check that the rubber insulation is in place on the flipper pawl where it contacts the EOS switch, or you could be grounding out the coil power into the flipper bracket. 

If both of those fuses are blowing, then the first common component in the circuits is the left side backbox rectifier.  Standard stuff there, 35amp 400v rectifier available everywhere, easy enough to test/replace. I assume you already put the additional fuses on one of the AC input legs for both rectifiers?   Also, solder the wires down on the rectifier legs, connections there can get corroded and cause all sorts of issues in the long term.   

-Hans

[lilshawn]

This is an earlier machine, with the System 6 power supply in it, so it's got a different fuse layout.

Power Supply Fuses:
F1 = Score display 90 volts AC, .25 amp Slow Blow.
F2 = Solenoids 28 volts DC, 2.5 amp Slow Blow.
F3 = Lamp matrix 18 volts DC, 8 amp Fast Blow.
F4 = Flippers 28 volts DC, 10 amp Slow Blow
F5 = +5 volts DC logic, 4 amp Fast Blow.

Sound Board Fuses:

F1 = 9.3 volts AC, 4 amp Slow Blow.
F2 = 9.3 volts AC, 4 amp Slow Blow.

Backbox Panel Fuses (located below power supply board on a fuse card):

6F1 Yellow Wires = General Illumination 6.3 volts AC, 20 amp Fast Blow.
6F2 Gray Wires = Logic 9.3 volts AC supply, 4 amp Slow Blow.
6F3 Gray Wires = Logic 9.3 volts AC supply, 4 amp Slow Blow.