(Topic ID: 241863)

2N5060 SCR: possible to test good and fail under load?


By Alan_L

6 months ago



Topic Stats

  • 16 posts
  • 9 Pinsiders participating
  • Latest reply 6 months ago by barakandl
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#1 6 months ago

I have a Bally lamp driver board that will not light four different lamps even though their transistors (2N5060) test good out of the game. Upstream, they go to three different IC's. Is it possible that they will fail in test mode and/or gameplay but pass an out of game diode test? If I put a separate ground jumper on the ground tab, they will light.

#2 6 months ago

Yes, I had them fail under load. But test fine with a meter.

#3 6 months ago
Quoted from Alan_L:

is it possible that they will fail in test mode and/or gameplay but pass an out of game diode test?

Yup.

#4 6 months ago

All the time. I had around 15 on my Meteor, and when I replaced them with used ones from other boards most of them would fail also. Took a while to find good ones.

#5 6 months ago

If I even suspect a 5060 that may be misbehaving, I replace it with a 2N5064. More often than not, it solves the problem without going in diagnostic circles.

#6 6 months ago

Thanks guys, I replaced a couple of 5060's that had tested good with new 5064's and now the feature lamps work fine.

Now, what can I do to fix a sticking star rollover button? It goes down when rolled over but the blade of the leaf switch doesn't push it back up. I don't know if it is a weak leaf or dirt in the rollover. I tried cleaning it with 91% alcohol, didn't do any good. Suggestions?

#7 6 months ago

If you don't want to replace the rollover star with a new clean one, you can gently pop out what you have and clean it. Probably wax build up on both the star and in the insert itself.

#8 6 months ago

Is the switch stack supposed to have a stiff blade to help with the spring back action?

#9 6 months ago

Pull the white star out carefully and then use a pipe cleaner to clean out the star insert. Clean the white star too.

Honestly, I cut the bottom of the white star so it is easy to get out and replace the white star with new ones from Pinball Resource. It is inexpensive and makes the game look that much better.

#10 6 months ago

I dont think you can fully test a SCR with just a DMM.

most common failure mode for scr is to never light up. Put your logic probe on the decoder chip output while in lamp test. If you see pulse like the rest of the working lamps, you are 100% sure the connectors/wiring are good, then the SCR is bad.

I usually don't even go that far. Make sure the connectors are good. Put the game in lamp test. Any lamp never on or always on, replace that SCR.

The decoder chips almost never fail. I have replaced probably 100 bad SCRs for every one bad decoder.

Adjust the switch blade to help give the star rollover more springy action.

#11 6 months ago

According to GPE, 2N5060s are obsolete, as are 2N5064s. I guess it’s time to stock up from another source if you can find them.

#13 6 months ago
Quoted from Billc479:

According to GPE, 2N5060s are obsolete, as are 2N5064s. I guess it’s time to stock up from another source if you can find them.

2N5064's are better to use. They have a higher voltage tolerance (200v) compared to 2N5060 (30v).

#14 6 months ago

On-Semi was the last major seller for these SCR's and discontinued them a couple years ago. I bought about 15K of these when On-Semi listed these on LTB list. I still have just over 6K remaining.
Since then - Central Semi has taken up the slack but at increased prices.

Littelfuse has taken over several product lines of SCR's and include some that are rated close to the 2N5060 series. One of these days - I gotta figure out which is closest to the 2N5064. Surely gotta be cheaper than the Central Semi parts.

Lastly -- damn, I love being on vacation!

#15 6 months ago
Quoted from G-P-E:

On-Semi was the last major seller for these SCR's and discontinued them a couple years ago. I bought about 15K of these when On-Semi listed these on LTB list. I still have just over 6K remaining.
Since then - Central Semi has taken up the slack but at increased prices.
Littelfuse has taken over several product lines of SCR's and include some that are rated close to the 2N5060 series. One of these days - I gotta figure out which is closest to the 2N5064. Surely gotta be cheaper than the Central Semi parts.
Lastly -- damn, I love being on vacation!

Glad I read this post. I had a couple lamp drivers with this problem. I did go ahead and change out a few of the 2N5060's even though they tested good. I jacked around with the DMM leads and tested in a bass-ack-ward way and I was able to discern which were actually bad (less jacking around with the schematics). I think I replaced them with 2N6051's I got from Ed long ago, or a while back anyway.

Have those gone the way of the dinosaur also?

May 3rd tomorrow, hope your rested up and ready for the avalanche brother?

One other thing I have done that's sorta' cool was to actually get organized by using the Plano plastic organizer boxes (Menards, Home Depot, Lowes) for all the stuff Ed and a few other sellers - sell. If you get lucky you can peel the label that comes on the bags from Great Plains and put it in the compartment of each device. Saves on using the label maker, on top of that Ed's labels have all the info for the device...cool like mad. I have a box for Gottlieb cpu's, Bally mpu's, Sound board caps, Solenoid driver rebuild stuff... and about 15 others. Watch out though, those boxes multiply like pinball machines.

Tim, Stillwater, MN

#16 6 months ago

MCR100 by Unisonic is a good sub. Unisonic is from Thailand and seem to be a good manufacturer. They still make TDA2003 too. Get them on LCSC. I have used few thousand of them by now. Work find on Bally LDB. Around 5 cents each.

https://lcsc.com/product-detail/Thyristors-TRIACs_Unisonic-Tech-MCR100G-6-AD-T92-B_C250647.html

https://datasheet.lcsc.com/szlcsc/Unisonic-Tech-MCR100G-6-AD-T92-B_C250647.pdf

The ChangChingCHong brand is probably fine too on LCSC, they are even cheaper.

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