ST TNG LED problem

[turbo27]

Decided to have a go and start refitting my ST TNG with LED's.

Before I started all current globes were working and appeared to activate correctly.

I swapped out ALL 555 globes under the playfield with LED's. All LED's were single's in either cool or warm. I did not replace any 44 globes.

I checked correct fitting and contacts as I went. All LED's were firing with the machine at idle ie: the machine ready to start a new game and displaying a light show.

It wasn't until I started a game (thinking how great it looked) that I noticed 2 if not 3 LED's were illuminating at the same time.

Went into test mode, and single lamps, and yep as you can see from the added picture of the lamp matrix 2 and sometimes 3 LED's are activating at the same time.

Let me explain my scribble. The blue highlight indicates the lamp being tested, and my handwritten number indicates the other lamp being lit.

Now there is certainly a common theme, and I have checked thoroughly all connections, wires and diodes for intact solder joints. All seems OK.

After exhausting my abilities and as a last resort, I changed all LED's back to globes, and problem appears to have gone.


Questions -
Are the globes masking an underlying problem?
Do I need to add or change something to make the machine LED compatible?
Or from my readings is there a faulty diode('s) on the column or row sending the LED's haywire?

Any advice or suggestions would be greatly appreciated.

Cheers

[turbo27]

Just realised I've added post to the correct topic but not into the correct sub category.

Sorry, should I try and move it, or delete and re create?

[Strangeways]

I've moved the thread to the "problems and assistance" sub section 

I have seen the cheap and nasty eBay LEDs create havoc in the lamp matrix. It sounds like a really bad case of "ghosting", but i've not seen it this bad.

Questions -
Are the globes masking an underlying problem?

No. The LEDs are the problem.

Do I need to add or change something to make the machine LED compatible?

No. LEDs are "plug and play"

Or from my readings is there a faulty diode('s) on the column or row sending the LED's haywire?

No.

Suggestion - Add small amounts of LEDs at a time. Check that the legs are straight on the LEDs. I've done a few ST TNGs with RTBB LEDs without Ghosting or any issues at all. The problem sounds like the LEDs.

[turbo27]

Thanks Nino,

Regards Trent