Replacing LED lights and smoke on restart

(Topic ID: 230637)

Replacing LED lights and smoke on restart


By crashpad

17 days ago



Topic Stats

  • 14 posts
  • 6 Pinsiders participating
  • Latest reply 10 days ago by crashpad
  • Topic is favorited by 2 Pinsiders

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Comet lighting 555 issue - 1 (resized).jpg
Comet lighting 555 issue - 2 (resized).jpg

#1 17 days ago

I am trying to replace my 555 bulbs on my Mr & Mrs Pac-man and started in the coin door.

At first, I couldn't get them into the sockets at all. I took a closer look and it seemed like the wires on both sides of the bulb were somewhat extended out from the bulb. I tried pressing them into the channel in the bulb, and was able to get two of them into the socket. The middle (red) light I still can't get in.

But to test the lights before screwing them back to the coin door, I turned the machine on, and when I did, the blue light gave off a tiny puff of smoke.

It still powered on and works, but what would have caused the smoke?

Comet lighting 555 issue - 1 (resized).jpgComet lighting 555 issue - 2 (resized).jpg
#2 17 days ago

Check your voltage....maybe you have put a 6.3V Bulb in a 12V line?.....

#3 17 days ago

Mr and Mrs pac is going to have one of the transformer assemblies that likely puts out high voltage. My Black Pyramid is the same way and certain LEDs would smoke / overheat because of it. I can't say for sure that is what is going on tho for you.

Check the voltage to ground of the feature lamps. Even after changing the transformer tap black pyramid was like 7.5vdc... it was just how the transformer was. I did a hack and sent the 7.5vdc through another rectifier just to get the voltage drop of a couple diodes. Clamped a 35a bridge to do so on the metal frame where the transformer is to heat sink. It doesnt really get warm tho with LEDs.

I learned that hack from seeing it on bunch of those rectifier boards that i would buy in bulk lots.

#4 17 days ago
Quoted from OLDPINGUY:

Check your voltage....maybe you have put a 6.3V Bulb in a 12V line?.....

Thanks for your help, OLDPINGUY and barakandI –

Yes, that is correct – I'd thought that 555 was all I needed (newbie to LED swaps)...

I checked the schematic and it shows General Illumination 5.9V AC, and the Pac Maze 5.4V DC; the order shows I bought 6.3V AC/DC Twin 2835 from Comet Pinball, but the bulbs themselves say 'AC'.

So it isn't as simple as having the correct bulb type, I also need to be aware of the voltages before swapping and whether AC or DC voltage?

I did check Comet's site, and the two wedge bases they show are #555 Bayonet (6.3V) and #906 Bayonet (12V), so possibly the coin door is 12V?

Is there a 'how-to' guide for converting various machines to LEDs here?

Thanks again for all your help, I appreciate it!

#5 17 days ago
Quoted from crashpad:

so possibly the coin door is 12V?

Put a meter on the socket and see what it is.

LTG : )

#6 16 days ago
Quoted from crashpad:

Thanks for your help, OLDPINGUY and barakandI –
Yes, that is correct – I'd thought that 555 was all I needed (newbie to LED swaps)...
I checked the schematic and it shows General Illumination 5.9V AC, and the Pac Maze 5.4V DC; the order shows I bought 6.3V AC/DC Twin 2835 from Comet Pinball, but the bulbs themselves say 'AC'.
So it isn't as simple as having the correct bulb type, I also need to be aware of the voltages before swapping and whether AC or DC voltage?
I did check Comet's site, and the two wedge bases they show are #555 Bayonet (6.3V) and #906 Bayonet (12V), so possibly the coin door is 12V?
Is there a 'how-to' guide for converting various machines to LEDs here?
Thanks again for all your help, I appreciate it!

That is correct. Schematic shows coin door should be 5.9 VAC. Take a meter and measure. Be aware that GI illumination is not regulated, so it can subject the LEDs to large spikes at power on, which probably smoked a component in your LED.

There isn't any single how to guide for LEDs because there are so many different LED technologies and so many different games. These games just weren't designed to have these sensitive solid state devices installed in place of filament bulbs.

#7 16 days ago
Quoted from crashpad:

.
So it isn't as simple as having the correct bulb type, I also need to be aware of the voltages before swapping and whether AC or DC voltage?

Read my post again. The bally games like Mr and Mrs Pac have transformers in them that put out high voltage.

Old Bally transformers (like Mata Hari, Silverball mania) usually see like 5.5vdc or feature lamps and 6vac for GI. The cabinet transformer on later bally games(like MR/s Pac) is a lot beefier and the windings put out higher voltage. Sometimes it is way higher like up to 7-8v

Because the current limiting resistor (value picked to achieve MAX BRIGHTNESS) is chosen for 6v instead of 8v, it goes over current and burns making that nice stink.

Test the voltages in your game. I am thinking you are going to find them very high and that is why the LED smoked.

#8 16 days ago

Thanks LTG, wayout440, and barakandI – will take another look and test it out to see.

#9 16 days ago

Of course, your voltage could be fine, and you could have have had a bad bulb, but likely, because you had issues getting them to fit, you might have had an issue there....another thought

#10 16 days ago

People who work on a lot of Bally games has probably seen this. They have probably also gotten these cabinet rectifier bally games where nearly every single bulb is burned out. It kinda follow every -54 rectifier / transformer setup but some games are worse. Check out this Black Pyramid. 7.8VDC on the feature lamps which will smoke certain LEDs for sure. Over voltage will dim them out faster too.

The Operator cut the feature lamp track on the rectifier board. Sent it through a couple diodes to get a voltage drop down to around 6vdc and he no longer had to replace feature lamps as often.

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before extra v drop
after extra v drop

The hack works as intended but I am not necessarily recommending it. Do at your own risk. Just trying to show why these Bally games DIM out and smoke LEDs faster than others. I am surprised this conversation does not come up more.

The issue shows up in GI too. Operator hack there is to rectify the GI to DC voltage which gives you some voltage drop across diodes.

#11 12 days ago

I ended up pulling the LEDs I'd installed back out – there was also (at least on the GI) flickering, and I found that I will need to put in classic Bally / Stern LED adapters to avoid that. About $75 total fix ($45 for the first one, and $30 for the Aux lamp board adapter). I will still need to test the coin door to see what happened, but not really clear why the 555 wedge base didn't fit right away. Good learning experience for me as I'm new to working on the machines.

Any suggestions for multimeters to buy?

#12 12 days ago

The one in the picture is pretty good starter meter.

Mastech MS8268
amazon.com link »

#13 11 days ago

Its the type of sockets that were used, there are different, I would think a lot of people have run it to this.

#14 10 days ago

Thanks for the multimeter suggestion, barakandl, I will check that out. Need a Christmas gift for myself!

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