Manchester, MI
Quoted from Quench:Can you post some pictures of the wires soldered to the transformer?
Sure... better than the ones I posted above?
(Topic ID: 208174)
I don't see any transformer pics in your gallery showing which lugs the wires are soldered to.
Though I can vaguely see from one of the pictures with the cage in front of the transformer that it looks like it's wired for 115VAC.
The beginning of the manual shows how to wire the input voltage at the transformer.
Transformer3 (resized).jpg
Change it to 120VAC. In all honesty it might make the issue worse, but there's enough weirdness in this that who knows. If it's not obvious cut the link between lug 9 and 11 when you move the yellow wire.
Quoted from barakandl:I do notice you have what looks like a 6mm x 30mm time fuse in F1. The clips are designed for 6.2mm x 32mm or 1.25" x 0.25" fuses like a MDL(slow) or AGC(fast) fuse in Bussman world. Hopefully I didnt put that fuse in the rectifier board when i sent it out. Anyways since it is a hair smaller, make sure it is fitting in solid and no resistance. I would probably put an AGC-10 fuse in there.
I don't have handy a 10A AGC fuse, but I did have a 10A MDL, so I put that in there. I hope that's ok. No difference in behavior.
Quoted from Quench:What's the likelihood all three of those wires have poor connections after you've re-terminated them all?
Zero.
Quoted from Quench:Try running a jumper wire from the lower leg of either white ceramic resistor on the rectifier board directly to the ground test point on the lamp driver board and see what happens. Be careful you don't jumper to the wrong spot and blow stuff up.
Done. No impact.
Quoted from jsa:Done. No impact.
I actually expected it might make the lamp issue worse since you now have slightly lower voltages out of the transformer compared to before.
Quoted from Quench:I actually expected it might make the lamp issue worse since you now have slightly lower voltages out of the transformer compared to before.
It's hard to see if it's marginally worse. The rate of the flicker seems about the same. It's interesting that the flicker rate isn't super random, it almost seems to pulse by design (which we know it does not).
Quoted from jsa:It's hard to see if it's marginally worse. The rate of the flicker seems about the same. It's interesting that the flicker rate isn't super random, it almost seems to pulse by design (which we know it does not).
...which also leads me to believe that the pulse is related to something on a beat/waveform that is consistent.
Quoted from jsa:That's helpful to know, but you're using an original Bally -18 rectifier or a repro?
Original.
Quoted from pinballinreno:That's good to know.
Did you convert to LED's?
Nope.
Quoted from jsa:I love doing this.
[quoted image]
Now that you've completed this restoration, I would like to say job well done and congratulations to both you and your son!! The machine looks absolutely stunning.
However, I can tell that this flicker issue is really getting the best of you. If you want to scrap the entire thing and sell to someone as a "project candidate", I'm willing to offer you absolute bottom dollar!! 
for your led flicker problem: Did you check the resistors on the lamp board? There is a row of them connected to each pin outgoing. I've converted many bally lamp boards to work with LEDs. If I miss one leg of a resistor when soldering, that bulb will flicker.
This is essentially the exact same thing Allteck is doing.
lamp (resized).jpgQuoted from brenna98:for your led flicker problem: Did you check the resistors on the lamp board? There is a row of them connected to each pin outgoing. I've converted many bally lamp boards to work with LEDs. If I miss one leg of a resistor when soldering, that bulb will flicker.
This is essentially the exact same thing Allteck is doing.
[quoted image]
The challenge is that the flicker happens with incandescent bulbs and with two separate lamp boards... and two separate MPU boards... so it has to be something else.
In my opinion, it’s something in my power wiring that I’ve overlooked. My next move is to swap the rectifier/transformer with a known working combo (not to solder myself). Let me absolutely get that ruled out. There is nothing left to try that I know of.
I have been following this saga for a while now and I recently bought a Future Spa myself. One question I have not seen tried is since we are talking about latching issues, have you tried your simple one socket test with 2 or even 3 incandescents loading down one SCR? Don't do it for long since the SCR won't last but if load and latching is still a concern this would eliminate load level as a thing.
Quoted from BJM-Maxx:I have been following this saga for a while now and I recently bought a Future Spa myself. One question I have not seen tried is since we are talking about latching issues, have you tried your simple one socket test with 2 or even 3 incandescents loading down one SCR? Don't do it for long since the SCR won't last but if load and latching is still a concern this would eliminate load level as a thing.
I'm not sure exactly if we've tried this. When you say a simple socket test, what do you mean? How would I do that? I've taken a socket, connected it directly to the SCR gate leg and to ground to make sure it stays on/latched, and that worked fine. I've also tried a socket, connected one lead to the single pin associated with that SCR and the other to the rectifier TP1, and that flickered in lamp test. My assumption here is that the SCR has the capability of latching based on that set of experiments. I've also swapped the SCR with a known working one, same results.
When we checked the waveforms hitting the SCR, there is no question a spike comes at the normal rate to make it latch, but it seems to not be strong enough for every two cycles, then successfully latches for two cycles. It's like something interferes with the voltage on a rhythm. It looks like it's not perfect (meaning, it's not precisely two on and two off), which leads me to believe whatever is doing this is on a slightly different cycle, but close.
Quoted from BJM-Maxx:I have been following this saga for a while now and I recently bought a Future Spa myself. One question I have not seen tried is since we are talking about latching issues, have you tried your simple one socket test with 2 or even 3 incandescents loading down one SCR? Don't do it for long since the SCR won't last but if load and latching is still a concern this would eliminate load level as a thing.
I have tried various increasing resistor values across even an incandescent (or LED) bulb on these flickering lamps, no change, if that's relevant.
One other clue that we uncovered in the other thread...
Most of the lamps that are address 1 or above on the decoder clear up after the game heats up for 5-10 minutes and stop flickering.
It's only the address 0 lamps (rollover F and SPA target) that keep flickering after warm up.
This means something heats up and changes the behavior. What changes when heated?
-Solder joints (but that would have to be the rectifier, since we swapped out the other boards)
-Resistors on the rectifier?
-Resistance increases?
-Something expands and moves a short circuit out of short?
-Metal pin or female connector trifurcon expands making better contact?
Quoted from jsa:One other clue that we uncovered in the other thread...
Most of the lamps that are address 1 or above on the decoder clear up after the game heats up for 5-10 minutes and stop flickering.
It's only the address 0 lamps (rollover F and SPA target) that keep flickering after warm up.
This means something heats up and changes the behavior. What changes when heated?
-Solder joints (but that would have to be the rectifier, since we swapped out the other boards)
-Resistors on the rectifier?
-Resistance increases?
-Something expands and moves a short circuit out of short?
-Metal pin or female connector trifurcon expands making better contact?
Maybe a current flow issue.
Not voltage.
More resistance after warming up.
Less current would lower the performance of the SCR, it would become slightly weaker and not latch properly.
Definitely power related.
Quoted from pinballinreno:Maybe a current flow issue.
Not voltage.
More resistance after warming up.
Less current would lower the performance of the SCR, it would become slightly weaker and not latch properly.
Definitely power related.
What would impact current flow? Pin connectors? Which power wire am I taking about here?
The first decoders output positions are most likely to show flickering assuming because of the timing of firing the SCR compared to where the feature lamp wave is. In this case the SCR fires when the wave is too close to zero to make enough current and flow. The CPU gets a zero X interrupt right when things are at zero. It begins to update the lamp picture starting at outputs 0 and work to 15. When it does output 0 the wave is still too low and not enough current flows and SCR doesnt latch. When the CPU gets to doing output 15 the feature lamp voltage is high enough everything latches no problem.
The pattern of missing probably depends on what the CPU is doing before it handles the interrupt. I'd assume some stuff may take priority over updating the lamps so if the CPU is working on something else it may finish that. Then jump to interrupt routine to do the lamps adding whatever time delay is needed so the SCR fires at a friendlier time.
The timing shouldnt be an issue tho as I can run Future Spa software in a test setup and get all sixty main lamp drivers SCRs to latch every time and all 12 aux lamps too while using LEDs. Makes me think resistance somewhere not letting enough current flow to latch the SCRs at the low position.
Ground return from xfrmer to lamp driver board??? Specially since you hooked the 6vdc feature lamp bus right at the rect board.
Quoted from barakandl:Makes me think resistance somewhere not letting enough current flow to latch the SCRs at the low position.
Ground return from xfrmer to lamp driver board??? Specially since you hooked the 6vdc feature lamp bus right at the rect board.
Well, based on the earlier Quench post, I attached a jumper from "the lower leg of either white ceramic resistor on the rectifier board" to the GND test pad on the LDB. It didn't seem to matter. I didn't bother re-terminating the three ground wires to the LDB, but I can do that next if you think it might have something to do with it.
When you say I hooked the 6VDC lamp bus right at the rect board...what do you mean exactly?
Quoted from jsa:Well, based on the earlier quench post, I attached a jumper from "the lower leg of either white ceramic resistor on the rectifier board" to the GND test pad on the LDB. It didn't seem to matter. I didn't bother re-terminating the three ground wires to the LDB, but I can do that next if you think it might have something to do with it.
When you say I hooked the 6VDC lamp bus right at the rect board...what do you mean exactly?
Oh I see...
Quoted from jsa:Most of the lamps that are address 1 or above on the decoder clear up after the game heats up for 5-10 minutes and stop flickering.
Have you run the hair dryer test yet? Alternatively using freeze spray to cool components down to see what's thermally affecting the flickering?
Quoted from Quench:Have you run the hair dryer test yet? Alternatively using freeze spray to cool components down to see what's thermally affecting the flickering?
I’d have to change the bulbs to LEDs to do that test since the bulbs that cleared are the same ones that don’t flicker with 44s. I’ll do that and hit it with the hair dryer test.
Quoted from jsa:I’d have to change the bulbs to LEDs to do that test since the bulbs that cleared are the same ones that don’t flicker with 44s. I’ll do that and hit it with the hair dryer test.
Still localizing... meanwhile, another glamour shot:
Heat gun tests have failed so far. After about 5 minutes, some incandescent lamps stop flickering when on. I have been presuming it was a warm up period in which something gets hot. I can't imagine another relationship. I have not replicated this with a socket directly connected to just one blinking LDB pin and TP! on the rectifier...I can make it blink, but not go solid, even with time.
I'm going to try this with LEDs and see if some of them clear up as well (they have resistors via the Alltek and the 6.3v rail).
Quoted from barakandl:Ground return from xfrmer to lamp driver board??? Specially since you hooked the 6vdc feature lamp bus right at the rect board.
I've now removed the connector housing from the rectifier J3 and replaced the whole thing with a molex style connector with obsessive, careful crimps, all identical. The connector has excellent contact on all pins. This includes the three ground returns from the LDB.
Just for giggles, I replaced all three ground returns to the rectifier on the LDB connector as well.
No change to any behavior.
Just an obvervation.
You have done everything except put the old rectifier board back in?
It might be informative to see the differences between the new and old while in service on your game.
It's a pain but really only a 1 hour job or less.
Quoted from pinballinreno:Just an obvervation.
You have done everything except put the old rectifier board back in?
It might be informative to see the differences between the new and old while in service on your game.
It's a pain but really only a 1 hour job or less.
Exactly, that's what I meant in my last post. This is my next move. I don't think I can just re-install it though, it had been hacked up in a way I'd have to rebuilt it somewhat and bullet proof it first, then I could use it in the original way. For example, certain power/ground lines had been directly soldered to the back of the board, and the ground was to the test pin, etc. It was a mess. However, as you saw from the photo, it's in good enough shape it can be cleaned up.
I ordered a kit from Big Daddy to clean it up. I'm not sure if I'll be using the Kulpa method or just following along a thread here on Pinside.
I just worry I'll go through this whole process and achieve no different result. It's worth it though, because then I'll have a backup rectifier.
Quoted from jsa:I just worry I'll go through this whole process and achieve no different result. It's worth it though, because then I'll have a backup rectifier.
Try not to be the glass half empty guy 
Quoted from pinballinreno:Try not to be the glass half empty guy
HA! I think given the full scope of this thread, we do a good job of "glass half full." And old buddy used to complain that I didn't give up enough.
Quoted from jsa:Exactly, that's what I meant in my last post. This is my next move. I don't think I can just re-install it though, it had been hacked up in a way I'd have to rebuilt it somewhat and bullet proof it first, then I could use it in the original way. For example, certain power/ground lines had been directly soldered to the back of the board, and the ground was to the test pin, etc. It was a mess. However, as you saw from the photo, it's in good enough shape it can be cleaned up.
I ordered a kit from Big Daddy to clean it up. I'm not sure if I'll be using the Kulpa method or just following along a thread here on Pinside.
I just worry I'll go through this whole process and achieve no different result. It's worth it though, because then I'll have a backup rectifier.
If you can manage it, since it was at least working, see if it works before you clean it up, just to verify. I know, it sounds like a bit of a hassle since it sounds like it's been really "route hacked", but you know it was working, it's just going to be an ugly reinstall. If you "clean it up" before reinstall, you may render it non-working, and then you may never find where the gremlin is without professional help making a house call.
And advice for next time: repair and/or replace those big parts before the teardown. It'll save you some post-restore grief with machine #3 knowing that replacement parts were installed and working correctly.
Quoted from LynnInDenver:If you can manage it, since it was at least working, see if it works before you clean it up, just to verify.
This is good advice. I think the only challenge with this approach is that every time the transformer is re-soldered to a rectifier, you're cleaning up the ends and shortening the leads, even by a small amount. I think I can do this, but probably only once without jumpers. In my perfect world, I would be able to do this with only non-permanent connections, but these earlier rectifiers were ugly in that way.
Quoted from LynnInDenver:I know, it sounds like a bit of a hassle since it sounds like it's been really "route hacked", but you know it was working, it's just going to be an ugly reinstall. If you "clean it up" before reinstall, you may render it non-working, and then you may never find where the gremlin is without professional help making a house call.
I understand your point. The connections in question were routed from the back of the board directly to a new cable connector to avoid the burnt pins. To simulate that would require I remove those specific trifurcons from the connector housing and somehow bypass the pins/traces on the board back to those solder points. That is a LOT of archaeology and the original bypasses have all been removed from the old rectifier. I took a lot of photography but I'm not confident I know which is which, and where the bypasses landed, so that is why I have been leaning on the idea of bringing the original back up to spec instead. I'll be honest though, I'm still not 100% sure the old rectifier is the way to go here. I've spent the better part of my career troubleshooting hard engineering problems, and I still feel like we're not answering the "why" question properly.
Given the nature of the problem (which is super weird), I'd frankly be happier pulling a transformer/rectifier combo from a friend's Future Spa that works, put it in mine, and see if that works before we go down this archaeological rabbit hole. That would isolate the rectifier board or not. If it turned out to be rectifier board related, we should find out why, what the actual differences are between my new one and the other one.
Quoted from LynnInDenver:And advice for next time: repair and/or replace those big parts before the teardown. It'll save you some post-restore grief with machine #3 knowing that replacement parts were installed and working correctly.
I agree with that. I should have done the rectifier swap before the teardown. I've generally believed that when there are volumes of text for a decade about the design flaws and failures of a specific piece of equipment leading to all sorts of mysterious problems, cutting out those flaky devices generally has been a good strategy...Even after a restoration...This is the first time I've seen it backfire. I doubt very highly there is anything wrong with the new rectifier...more likely I wired something wrong.
...it's also worth noting we've had people post here saying they are using an original Bally -18 rectifier board in place of the specified -49 without problems. It's not a barakandl reproduction but it's pretty much the same thing (the reproduction has improvements, but operates the same). That's more evidence it's our wiring!
Quoted from jsa:barakandl just double checking: Am I correct in saying there are no differences between your -18 and the original -49 that could *possibly* have anything to do with this, right? I’ve literally got nothing left to try.
The feature lamp circuit is the same. Just the -49 board uses dual diodes to be able to handle more current and there is an extra header pin. The -18 replacement has the extra header pin and the diode bridge is able to handle the high current. The rectifier board is probably the most popular item I sell so lots of the rectifier boards out there and I know at least a handful if not many have replapced the -49 rectifier without any problems. I know a guy with the full LED treatment with a space invaders (-49 originally) and know issues with flickers. I can run future spa on a test setup with same rectifier no issues.
I really doubt the rectifier board itself is the problem. Specially with the wave form reading you took looked OK. Unless the bridge has has a bad diode internally which seems unlikely since it is a brand new part from On Semi or Fairchild.
Looks like the CPU is updating the lamp picture too early compared to the wave of the feature lamp voltage by testing I have done. All i have to do to get your results is to speed up the CPU clock and the lower decoder positions begin to flicker like your example. I don't know about the Alltek MPU, but you can slow down the original Bally MPU's CPU clock by tinkering with cap/res values. I run my replacement MPUs at 0.5mhz and that seems fine. Original Bally MPUs vary clock speed do to tolerance of resistors and caps(-10%/+20% caps) in the clock circuit. I can't really speak to what Alltek CPU clock is or if there is any easy way to slow it down.
What is the CPU clock running at? cpu p37 frequency check.
Quoted from barakandl:I really doubt the rectifier board itself is the problem.
Agreed.
Quoted from barakandl:Specially with the wave form reading you took looked OK. Unless the bridge has has a bad diode internally which seems unlikely since it is a brand new part from On Semi or Fairchild.
If the bridge had a bad diode internally, wouldn't that result in far more problems than we are seeing? Seems unlikely.
Quoted from barakandl:Looks like the CPU is updating the lamp picture too early by testing I have done. Alll i have to do to get your results is to speed up the CPU clock and the lower decoder positions begin to flicker like your example.
Given that this happens with two separate (original Bally and Alltek) MPU boards... How on earth could my clock be going faster now than before the restoration?
Quoted from barakandl:I don't know about the Alltek MPU, but you can slow down the original Bally MPU's CPU clock by tinkering with cap/res values. I run my replacement MPUs at 0.5mhz and that seems fine. Original Bally MPUs vary clock speed do to tolerance or resistors and caps(10%/+20% caps) in the clock circuit. I can't really speak to what Alltek CPU clock is or if there is any easy way to slow it down.
The Alltek is designed to be adjusted between the Bally clock and the (faster?) Stern M-200s, whereas the Bally doesn't adjust. It's a jumper, I'll look into it.
Quoted from barakandl:What is the CPU clock running at? cpu p37 frequency check.
I'll check that out today. Note that I'm currently using the original Bally MPU. I used both successfully before the restoration with no problems.
Quoted from jsa:If the bridge had a bad diode internally, wouldn't that result in far more problems than we are seeing? Seems unlikely.
Not necessarily a blown open or shorted internal diode, but one with far different V-drop than the other three. Again does seem highly unlikely.
Quoted from jsa:Given that this happens with two separate (original Bally and Alltek) MPU boards... How on earth could my clock be going faster now than before the restoration?
I don't know but it is worth checking since a faster CPU clock gives your exact symptoms i'd say the issue is timing somewhere in regards to zero cross, the feature lamp wave, and when the CPU updates the lamp picture. SCR fires too early and the wave is too low so not enough current draws across the SCR to keep it latched is my assumption.
Here is an example of how I can make q14 and q29 flicker running future spa software by increasing the cpu's clock speed. The lamps that end up flickering vary SCR to SCR (ldb to ldb) but always begin at or near decoder output position 0.
I don't exactly know the order the cpu/software updates the lamp picture but Q14 and Q29 are presumably the first two lamps to be updated.
Quoted from barakandl:Here is an example of how I can make q14 and q29 flicker running future spa software by increasing the cpu's clock speed. The lamps that end up flickering vary SCR to SCR (ldb to ldb) but always begin at or near decoder output position 0.
I don't exactly know the order the cpu/software updates the lamp picture but Q14 and Q29 are presumably the first two lamps to be updated.
I’d say you figured out how to precisely replicate my problem. That is super bizarre. I’m still trying to wrap my head around how both boards would be running too fast. Going to check CPU pin 37 speed next.
Quoted from jsa:Ok barakandl I hate to be a complete idiot but I must be missing something in the procedure. DMM set to Hz, black lead to ground, red lead to p37 on the 6800P on the Alltek, right?
yep. Hz mode of DMM. Black lead on ground and red lead on P37 of the CPU chip. Should be around 0.5mhz or 500khz. Much higher speed than that and you can see the flickering begins. Presumably because the CPU updates the lamp picture before the feature lamp voltage is high enough to latch all the SCRs.
Quoted from barakandl:yep. Hz mode of DMM. Black lead on ground and red lead on P37 of the CPU chip. Should be around 0.5mhz or 500khz. Much higher speed than that and you can see the flickering begins. Presumably because the CPU updates the lamp picture before the feature lamp voltage is high enough to latch all the SCRs.
Alltek reads .553 MHz.
Quoted from jsa:Alltek reads .553 MHz.
I just checked an original bally mpu and got 0.505mhz. The working example shown above was a nvram.weebly mpu running 0.500mhz bang on because a fixed crystal is used.
Is that extra 50hz in clock speed going to make the feature lamp flicker.....? i dont know but the faster speed is for sure not helping. I can't tell you how to slow down the alltek mpu but tinkering with small changes on the original bally MPU resistors (or caps)in the clock circuit can give you speed adjustment.
Promoted items from Pinside Marketplace and Pinside Shops!
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+!
