LEDs stay on Dim on certain machines - is there a fix?

[Marty Machine]

Hi All,

I was putting a few LEDs into a playfield today and although the end results are bright & colourful, i now notice that the LEDs stay on dimly, but not dim enough to ignore...

Has anyone seen a mod/fix to eliminate this?

Obviously regular globes 'hide' the problem, as the filament doesn't have time to illuminate with the fast scanning pulses cycling thru the lamp-matrix.
However, LEDs are far quicker than lamps, and seem to capture all clocking/cycling in the matrix and illuminate accordingly.

I haven't dug any further yet, why re-invent the wheel if someone's already solved it?

Otherwise, i'm probably looking at adding a diode in series with EACH lamp socket (or each line in the matrix plug), and hopefully the 0.6v drop will kill off the residual pulsing, or (at worst case) some form of blanking circuitry that will plug inline between the lamp-matrix connector and the lamp-loom.....

anyone?
MM.

[pinnies4me]

They call it "ghosting" (or flicker) when a LED glows dimly when it should be off - I think it's called "ghosting" because it's to do with a switch in the same row etc being on that causes it.

I have seen mention of hacked ROM for WPC games to stop this, but as I am not that big on LEDs (other than in certain places) haven't gone much into it. Should be stuff around, just google "Pinball LED ghosting".

[dj10555]

You can also buy non flickering LED

[Caveoftreasures]

There is a range of patched (updated game code) game ROMS mostly for WMS machines that are anti flickering or anti ghosting in design. I have had Beaky(Andy) fit them to some of my Williams machines like Star Trek Next Generation and ALL the ghosting/flickering stops instantly.

Contact Beaky(member here) for a list of available ROMS or search ghost roms on the various USA ansd Aussie Pinball websites.

[Retropin]

Do you really have to change the ROMs?
The ghosting would only exist because lamps are held high and then sunk to ground to turn on... ghosting is there due to a potential difference that shouldnt exist, in other words, the high isnt equal on both sides of the LED.
Got to be an easier way other than new ROMs?

[Homepin]

Do you really have to change the ROMs?
The ghosting would only exist because lamps are held high and then sunk to ground to turn on... ghosting is there due to a potential difference that shouldnt exist, in other words, the high isnt equal on both sides of the LED.
Got to be an easier way other than new ROMs?

It's a little more complex than that. In some machines the software was written to pass a small current through the lamps to prolong the life and also to ensure they light up straight away. LEDs are sensitive to this and so new software is required to take out the 'preheat' parts.....hence, new ROMs

[Cow Corner]

You can also buy non flickering LED

+1
Cointaker premiums or Pinball life non ghosting leds will fix this quick smart.

[Homepin]

You can also buy non flickering LED

+1
Cointaker premiums or Pinball life non ghosting leds will fix this quick smart.

maybe they have a diode built in???????

[Cow Corner]

You can also buy non flickering LED

+1
Cointaker premiums or Pinball life non ghosting leds will fix this quick smart.

maybe they have a diode built in???????

I'm not sure Mike but they sure as hell do the job well.

[Caveoftreasures]

Dont waste ya money on expensive anti ghosting LEDs unless you have to. The ROMS with the ghost patch are very cheap at a few bucks each only compared to a whole machine of the expensive anti ghost LEDS etc.

It only becomes a issue when the patched ROM isnt available to a certain machine but the list is growing that the patched ROMS are available for.

Shop around cause every different seller charges different prices on LEDS. Best to buy in bulk, share a order with a mate or two and get the LEDs much much cheaper. Also, the ghosting is usually only a issue in a very small number of inserts on most machines, and only for a nano second or so. I have done full LED jobs to over a dozen machines so far and its only a very minor issue. You would only have to change over to a very small amount of anti ghost LEDS versus doing the whole machine. hope it helps.

[Cow Corner]

Dont waste ya money on expensive anti ghosting LEDs unless you have to. The ROMS with the ghost patch are very cheap at a few bucks each only compared to a whole machine of the expensive anti ghost LEDS etc.

It only becomes a issue when the patched ROM isnt available to a certain machine but the list is growing that the patched ROMS are available for.

Shop around cause every different seller charges different prices on LEDS. Best to buy in bulk, share a order with a mate or two and get the LEDs much much cheaper. Also, the ghosting is usually only a issue in a very small number of inserts on most machines, and only for a nano second or so. I have done full LED jobs to over a dozen machines so far and its only a very minor issue. You would only have to change over to a very small amount of anti ghost LEDS versus doing the whole machine. hope it helps.

Cointaker premiums or anti ghosting are needed for Stern pins to stop ghosting, can't get a patched rom for them.

[Caveoftreasures]

anything older than ac/dc sterns equal yes for some ghosting etc.
Daz, I have written to Stern and asked about rom patchs that i have heard may be avail for older STERNS etc.
I will pass on any info i get back via email.

[Marty Machine]

Thanx guys for the input,

To clarify, this is a brightness (not off) issue, NOT a flickery issue......

I don't believe there's a big enough library of patched roms and across all brands, that's a long way off, if ever...

Special "non ghosting LEDs" probably also don't guarantee 100% results with the variations of driver types etc...and then there's the issue of mixing them with other leds, hopefully they're coloured/marked in a special way.


I still feel a diode mod is in order, cheap and accessable to anyone, instead of waiting for a rom that (may) never be patched.
I was thinking initially about adding dropper resistors to drop off of 5mA or so to kill the LEDs, but with so many variations in leds and driver circuits it may work on some brands and not others....i still feel dropping just .6v off the LEDs with a diode will work, but yet to be proven ;-)
Perhaps just some bleeder resistors on the matrix lines will pull the voltages low enough? - to also be proven.

Anyway, here's some OFF & ON pics of the sames LEDs on my Gottlieb "Class of 1812"...

LEDs are OFF......(or should be OFF......not exactly un-noticable are they?



LEDs are ON as expected. (notice the 2x and 3x are dim, coz they should be OFF in this chase-cycle).



MM.

[Caveoftreasures]

yeh it is very noticeable on that machine. For some reason, it doesnt seem to ghost so much on some data east/sega games anywhere as much on some williams/bally and gottlieb titles. I have had a very mixed result with ghosting on the various machines I have added lots of LEDS too.

you are spot on marty about what u have said about so many machines having so many variances. pain in the bum, but the only way to tell is to keep playing around with different Leds.

[Homepin]

There is a software program available that 'fixes' the issue is practically all WMS machines - you simply run the program with the appropriate WMS ROM for your game and it sorts it out - reprogram the chip and it's fixed.

Gottlieb,,,,,,well - they always were - and still are a pain in the arse!