Strikes and Spares
Bally, 1978Bought a new Rottendog rectifier after rebuilding 3 boards. All test points are good except TP3 I'm getting 6.5v. This is with J2 only plugged in. I tried 4 transformers and I'm still getting the same thing. Did I blow the 12v on the transformer? Can it be fixed? I repinned J1,2 and 3. I didn't do anything to the SDB. So far the only good that has come of this, I bought a new Hakko 888 and FR300.
image.jpgIs c23 connected on the driver board? Check the AC reading on the transformer too. Use the transformer drawing to find the two ac points of the 12v bridge.
Since you are only getting half of your 12volts dc, I would say only half of your Bridge Rectifier
is working.
I doubt you have 4 bad power Transformers !
Transformer.... Remove F3 and check the voltage across E11-E12
@ s/b 12v. ac
Bridge Rectifier..... if your transformer reads ok.
@ BR is bad
@ missing/bad ground connection on BR.
*** Check your Pinside mail
John
Quoted from barakandl:Is c23 connected on the driver board? Check the AC reading on the transformer too. Use the transformer drawing to find the two ac points of the 12v bridge.
I replaced C23 to eliminate that. Can't find a transformer schematic. Still looking.
Here is a link to the schematic:
http://mirror2.ipdb.org/files/2406/Bally_1978_Strikes_and_Spares_Manual_w_Schematics.pdf
The rectifier board is on page 42 and 43. Turn your DMM to VAC and place one lead on E11 and the other on E12. If your transformer is working correctly, you should have 12 VAC.
Quoted from JKnPA:Since you are only getting half of your 12volts dc, I would say only half of your Bridge Rectifier
is working.
I doubt you have 4 bad power Transformers !
Transformer.... Remove F3 and check the voltage across E11-E12
@ s/b 12v. ac
Bridge Rectifier..... if your transformer reads ok.
@ BR is bad
@ missing/bad ground connection on BR.
*** Check your Pinside mail
John
Quoted from BallyPinWiz:Here is a link to the schematic:
http://mirror2.ipdb.org/files/2406/Bally_1978_Strikes_and_Spares_Manual_w_Schematics.pdf
The rectifier board is on page 42 and 43. Turn your DMM to VAC and place one lead on E11 and the other on E12. If your transformer is working correctly, you should have 12 VAC.
I'm getting 13.1, most encouraging thing all night. 
Quoted from Pin-one:Noticed on the plug that the ground post was cut off. Could this be causing my issue?
No, this would not be affecting your lack of 13 volts DC at TP3.
So, let me be sure I understand you correctly. You have 4 separate transformer and rectifier board assemblies (the one pictured in the machine and the 3 on your bench). When you hook up 120 volts to the transformer (via a connected J2 connector), you get 12 volts AC at points E11 and E12. However, when you switch your digital voltmeter to DC volts, and place the red lead on TP3 and the black lead on ground, you only get 6.5 volts DC on all four units?
Quoted from BallyPinWiz:No, this would not be affecting your lack of 13 volts DC at TP3.
So, let me be sure I understand you correctly. You have 4 separate transformer and rectifier board assemblies (the one pictured in the machine and the 3 on your bench). When you hook up 120 volts to the transformer (via a connected J2 connector), you get 12 volts AC at points E11 and E12. However, when you switch your digital voltmeter to DC volts, and place the red lead on TP3 and the black lead on ground, you only get 6.5 volts DC on all four units?
That is correct. To make things worse, when I plug in J3 my voltage goes to zero on TP3. The transformer on the left had 12v until I plugged in J3, now like the other two I'm getting 6.5 volts. I'm not touching the fourth transformer. I didn't plug in J3 with it. It's in my Night Rider now.
Check your PinMail..................
If you have 13Vac across E11-E12 and your getting 6.5Vdc at TP3 .............
It seems like something is Miswired between the Transformer inputs and your E9-E12 points.
It seems like you have the 7.8Vac and the 12Vac input lines reversed.
Check your transformer wiring that is connected to your board. I don't see it; is it connected behind the board.
* transformer terminals 15-16 are the 12Vac inputs
" " 13-14 " " 7.8Vac
Quoted from JKnPA:If you have 13Vac across E11-E12 and your getting 6.5Vdc at TP3 .............
With proper voltage measured as 13Vac across E11-12, I highly doubt that it is anything else other than the only component in circuit - the bridge rectifier. Why not just test the bridge rectifier? If you have an open diode cutting off half of the AC cycle you will have half of the ripple frequency (60HZ instead of 120HZ) and a much lower output voltage. You can pull the bridge and check each diode with a meter, or you can use an oscilloscope, frequency counter or DMM with a frequency measuring function to check the output in circuit.
All 3 units are doing the same thing........... that's pretty high odds all of them are bad! IMO.
Yes... If he installed the Bridges himself, he may have put them in wrong.
If E11-E12 are wired correctly...... then its a Bridge problem or missing ground!
Quoted from JKnPA:All 3 units are doing the same thing........... that's pretty high odds all of them are bad! IMO.
I do agree. I think it best to use the tools to find out what is going on. There's really not much on this board to look at if the transformer is supplying the correct ACV at the bridge. We are also assuming measurements are being done correctly, and also could be measuring wrong if negative lead of meter is not referencing actual ground (in other words if ground is floating at 6VDC then you would be measuring 6VDC at TP3)
Right ....... I mentioned and posted a picture of the ground connection.
Evidently these boards are a major problem.
I just got a Mata Hari with a 'smoked' board and a transformer with the high voltage
terminal GONE........ Ugh.
These boards should never have been 'hard wired'....... too many potential problems!
I had a DMM many years ago that suddenly went bad. The AC voltage would read fine, but when I switched it over to DC voltage, it would only display a fraction of the actual voltage. If the OP is getting 6.5 volts DC on all of his assemblies, maybe there is a problem with the DMM.
Quoted from vid1900:Can you post a pic of where you have the leads plugged in ?
As Vid mentioned in his post, a picture of your DMM leads attached to the rectifier board assembly would show us if you are taking the voltage measurements at the right spot.
Quoted from JKnPA:Check your PinMail..................
If you have 13Vac across E11-E12 and your getting 6.5Vdc at TP3 .............
It seems like something is Miswired between the Transformer inputs and your E9-E12 points.
It seems like you have the 7.8Vac and the 12Vac input lines reversed.
Check your transformer wiring that is connected to your board. I don't see it; is it connected behind the board.
* transformer terminals 15-16 are the 12Vac inputs
" " 13-14 " " 7.8Vac
Very Nice job........ So where are we now ?
You verified the the voltage at E11-E12 is 12Vac........ Yes or No ?
All the other TP voltages are correct........ Yes or No ?
Did this board fail in the machine or are you just bench testing it before you install it ?
Did the other two boards fail in the machine ?
That's really not a great way to test a bridge rectifier, it would be best to remove the bridge to test properly. Use the diode setting on your meter and work your way around the bridge. On each set of terminals take a reading in both directions, for a total of 8 readings ( 2 reading on each diode ). The diodes will read OPEN in one direction & the breakdown voltage will be shown on the meter in the other direction ( typically .4-.6volts ).
Quoted from Pin-one:Verified 12 vac good.
All TP voltages are good except TP3
Passed on bench, failed in machine.
Yes all boards failed in the machine.
Bridge test photo's first photo is BR1' second BR2 third BR3. Red lead on neg black on pos.
......................................................................................................................
If all these boards failed in the machine( Strikes & Spares ?) and all the dc voltages are
WRONG at TP3........ that tells me the problem is at J3-8.
J3-8........ 5V Regulator/C23/C24/C29
* All 3 BR2 rectifiers are most liked Blown....... IMO.
** When you check a Diode, you have to check in both directions
@ Forward and Reverse bias (reverse the leads)
Keep at it...... don't give up the Ship.
John
*** Wayout,
I was writing while you posted, so I didn't see your comment about diode testing.
Didn't mean to be redundant.
Quoted from wayout440:No problem, JKnPA
I'm a slow typer and try not so say stupid things..... 
Just thought I would add this......... diode checking !
I like to use my analog multimeter to check diodes because that is what I always used at work.
I have a new digital multimeter( cheap O) from harbor freight, but I'm not quite sure how good it
is when checking diodes.
Anyway............
Analog test
Digital meter
While 'Pin-one" is waiting for his new soldering iron to arrive........
Question: Does anyone sell just the 'bare board' for this assy. ?
I know you can buy kits to replace parts, and a totally new board.
But what about just replacing the bare board if it has some severe burn marks.
I did a Search......but I found nothing !
John
Talk to one of the manufacturers of these aftermarket boards. You might find someone who will sell you one
Quoted from JKnPA:While 'Pin-one" is waiting for his new soldering iron to arrive........
Question: Does anyone sell just the 'bare board' for this assy. ?
I know you can buy kits to replace parts, and a totally new board.
But what about just replacing the bare board if it has some severe burn marks.
I did a Search......but I found nothing !
John
Quoted from barakandl:Talk to one of the manufacturers of these aftermarket boards. You might find someone who will sell you one
Thanks......
I guess the market( Volume) isn't there for retailers to sell them.
I'm thinking if I have a burnt board with only one or two bad components, I may want to replace the board too.
John
You can't really measure across terminals that way with one reading.
On each set of terminals take a reading in both directions, for a total of 8 readings ( 2 reading on each diode ). The diodes will read OPEN in one direction & the breakdown voltage will be shown on the meter in the other direction ( typically .4-.6volts ).
Quoted from wayout440:You can't really measure across terminals that way with one reading.
On each set of terminals take a reading in both directions, for a total of 8 readings ( 2 reading on each diode ). The diodes will read OPEN in one direction & the breakdown voltage will be shown on the meter in the other direction ( typically .4-.6volts ).diode-testing.gif 12 KB
Thanks wayout, I did watch a video on testing bridge rectifiers. The only reading I got is what is in the picture. I did check pos to neg, neg to pos. I had to use my nose to Hit the button to take the picture. Not easy and glad my wife did have to see that! What has me confused is this is a new Rottendog board. What are the chances they are bad?
Quoted from Pin-one:Thanks wayout, I did watch a video on testing bridge rectifiers. The only reading I got is what is in the picture. I did check pos to neg, neg to pos. I had to use my nose to Hit the button to take the picture. Not easy and glad my wife did have to see that! What has me confused is this is a new Rottendog board. What are the chances they are bad?
The picture still shows you testing incorrectly, across the bridge and not adjacent pins. I don't know what video you watched, but that's an incomplete test. Each of the 4 diodes on the bridge should be checked for forward voltage drop in one direction and be open in the reverse direction, and they are measured from adjacent pins, not from where your leads are. From the information you presented I cannot say with certainty that the bridge is good or bad.
350129-i.jpgVery Good Wayout........ I didn't see that in the picture. too much black stuff! LoL.
I posted the video in my post testing with an analog and Digital
multimeter for diodes; it was not a Bridge, so I guess it didn't help.
When testing you have to look at the schematic for test points.
* Just noticed that test he did shows something! I believe you should read OPEN testing that way, because one diode will always be reversed-biased either way you put the leads.
Check it out.....
*** I'm thinking all the BR2 bridges are blown. I think Q2 on the solenoid board is the
problem.
Just my thoughts.
**** BTW...... thanks for sending the snow this way..... 
Quoted from JKnPA:* Just noticed that test he did shows something! I believe you should read OPEN testing that way, because one diode will always be reversed-biased either way you put the leads.
On these two points you are measuring the sum total of 2 pairs of diodes in a series-parallel combined circuit. Yes you will see some measurement, but you can have all sorts of problems with the diodes and not really know what you are looking at.
Ok............ you are correct with those two particular leads; but the other way I believe its an Open
circuit because one diode will be reverse biased.....
Thanks for pointing that out. 
Anyway........... that is not the correct way to test the Bridge......as you stated!
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Solon, OH
Sana'a
