(Topic ID: 182901)

Help with new bridge rectifier


By Spraynard

2 years ago



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  • 15 posts
  • 5 Pinsiders participating
  • Latest reply 2 years ago by Spraynard
  • Topic is favorited by 1 Pinsider

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Wire_Error (resized).jpg
E9-E10 (resized).jpg
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IMG_6591 (resized).JPG

#1 2 years ago

I recently picked up a project Stern Big Game. The original bridge rectifier was toast, and I just got finished dropping in a replacement from Great Plains electronics (for reference, it is this one: https://www.greatplainselectronics.com/proddetail.asp?prod=135-105).

After wiring it up, repinning connectors, etc., I checked the voltages at each of the test points. Below are what the points *should* read, followed by what they actually read:

1. TP1 - 6.4; 1.6
2. TP2 - 195; 250
3. TP3 - 12; 12.83
4. TP4 - 7.3; 6.1
5. TP5 - 43; 45.9

TP1 and TP2 are well outside the normal range, TP4 is slightly lower than the acceptable range. I double checked all the wires and made sure there were good connections. The game boots fine, and I can start a game. However, none of the solenoids fire and the GI on the playfield appears rather dim. Other symptoms include super garbled sound, however I don't know if that is related.

Any help or advice on what to check would be most appreciated. Thanks!!!

#2 2 years ago

First thing I'd suspect is across or through board continuity.

LTG : )

#3 2 years ago
Quoted from LTG:

First thing I'd suspect is across or through board continuity.
LTG : )

Can you elaborate a bit? Not quite sure what you mean

#4 2 years ago

I'm new to all of this...

TP2 looks like it's ok. The schematic says 230v. TP1 is supposed to be 5.4v

Here's the schematic I got that from.

http://mirror2.ipdb.org/files/249/Stern_1980_Big_Game_Schematics_And_Wiring_Diagrams_Hi_resolution.pdf

And a mistake I've made over and over working on one game? TP4 is AC. Just in case your doing what I did! I kept checking it in dc.

#5 2 years ago
Quoted from Joker2415:

I'm new to all of this...
TP2 looks like it's ok. The schematic says 230v. TP1 is supposed to be 5.4v
Here's the schematic I got that from.
http://mirror2.ipdb.org/files/249/Stern_1980_Big_Game_Schematics_And_Wiring_Diagrams_Hi_resolution.pdf
And a mistake I've made over and over working on one game? TP4 is AC. Just in case your doing what I did! I kept checking it in dc.

Thanks Joker! The board I am using is a replacement with a slightly different design. The info a schematics are here: https://www.greatplainselectronics.com/Downloads/Rectifier_Ver5.pdf

For this board, it wants 195 at TP2, with a range of 190 to 220, so the 250 I'm seeing is too high.

Yes, I did make note that TP4 AC! I made the mistake early too

#6 2 years ago
Quoted from Spraynard:

Thanks Joker! The board I am using is a replacement with a slightly different design. The info a schematics are here: https://www.greatplainselectronics.com/Downloads/Rectifier_Ver5.pdf
For this board, it wants 195 at TP2, with a range of 190 to 220, so the 250 I'm seeing is too high.
Yes, I did make note that TP4 AC! I made the mistake early too

I should of looked at your link first. I see what your saying now.

#7 2 years ago

So the through board continuity means did the solder flow through the hole to the other side of the board? On the BRs it's common for it not to and to have the component side not connected to the BR. If you left room under the BR you can inspect and reach under with you soldering iron to add solder on the topside.

#8 2 years ago
Quoted from Cheddar:

So the through board continuity means did the solder flow through the hole to the other side of the board? On the BRs it's common for it not to and to have the component side not connected to the BR. If you left room under the BR you can inspect and reach under with you soldering iron to add solder on the topside.

Oh I see. Indeed there were a few points that had poor flow through with the solder. i made sure all points had good solder on both sides of board. Alas, no change in readings. However, I noticed the F1 fuse was blown. When I replaced it and powered it on again the F1 fuse blew yet again.

#9 2 years ago

On that particular board -- ALL high current connections are to the bottom of the board, there are no high current connections solely on the top of the board so through holes are never a problem. Majority of connections on top layer are test points, MOV connections, a couple low current connections, one redundant high current connection (GI) plus lots of redundant ground connections.

Don't worry about the HV voltage -- that one has a typical range but in real life, he varies quite widely depending on his load.

The switched lamp voltage, on the other hand, is an issue.
When you power this up - what is connected to J1 and J3?
Particularly J3, pin 6. J1 pins 3, 7 and 9.

With fuse F1 pulled -- can you measure the AC voltage between E9 and E10?

#10 2 years ago

Not sure what you mean by what is connected to them, but here is a photo.

As for ac voltage between those points, it is about .02 V.

IMG_6591 (resized).JPG

#11 2 years ago

one peculiarity I discovered was that there seems to be continuity between two lugs on my transformer (see photo). These wires are black and blue in color. They connect to points E8 and E7 on the board, respectively. So there is continuity between these points. I'm not sure this is normal? Based on my reading of the schematics, I would think no...

FullSizeRender (resized).jpg

#12 2 years ago

OK -- quick look suggests that the switched lamp output may be shorted.
First thing I would do is narrow things down a bit. Unplug connectors from J1 and J3 to see if this TP1 brings voltages back up.
With fuse F1 pulled -- did you measure directly from E9 to E10 (see circled in pix) with meter in AC setting?

Your wires that connect to E7 and E8 -- you are measuring directly across the GI output winding. That will look like nearly a dead short with an ohm meter.

E9-E10 (resized).jpg

#13 2 years ago

... edited post.
Don't 'stutter' on mouse button when pushing the "Submit post" button.

Hey, just noticed something in photo. Stern Big Game -- his J1 was originally an 8-pin connection. This board provides 9-pins to work with old and new games. For older games such as yours -- the 9th pin should be empty.
Looking at photo -- do you have wires in J1, pins 6, 7 and 8 accidentally shifted by one pin to pins 7, 8 and 9? This would do mean and nasty things to your TP1 votlage and probably buggerer Tp4 as well.

Wire_Error (resized).jpg

#14 2 years ago

Might want to check other wires as well.
J2 -- pin 7 (AC power return) should be white. But if this wasn't connected to AC return already, nothing would work. A stern documentation error in wire color? Might check him to be safe.
On J2 -- I see an orange wire in pin 9. Manual does not show such a wire... but could be another documentation screw up in the Stern Manual. Maybe somebody else with a Stern Big Game can check this one.
Pin 3 connections look good based on this pix.

#15 2 years ago
Quoted from G-P-E:

... edited post.
Don't 'stutter' on mouse button when pushing the "Submit post" button.
Hey, just noticed something in photo. Stern Big Game -- his J1 was originally an 8-pin connection. This board provides 9-pins to work with old and new games. For older games such as yours -- the 9th pin should be empty.
Looking at photo -- do you have wires in J1, pins 6, 7 and 8 accidentally shifted by one pin to pins 7, 8 and 9? This would do mean and nasty things to your TP1 votlage and probably buggerer Tp4 as well.

You are right! When I re pinned the connector, I didn't recognize I was going from 8 pin to 9! I moved those over and everything tests out fine. Thank you! I'll check the other wires to be safe, but I pretty methodically recreated what the original connectors were. Fool proof unless the number of pins change, lol.

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