Battlezone monitor repair needed

If 3 of the frame transistors were identical, that could be part (or maybe all) of the issue, as one of them is wrong. There should be two 2N3716's, and two 2N3792's. The NTE might be a substitute for a 3792, but three 2716's definitely isn't right.

That said, it may have just blown the fuses, but it also could have damaged other active parts on the PCB. You should test all transistors on the deflection board with your DMM, looking for shorts between any of the 3 pins, and checking them using the 'two diode' method (google how to test transistors if needed).

If all of the transistors on the deflection board check out ok, you could try replacing everything, and firing it up. Worst case things will blow again, and parts on the PCB may burn up. In which case you can trade it in toward a rebuilt one (which I have).

Yeah I got that wrong. I edited my above post. there were (2) 3792s and (1) 3716 and (1) NTE284
 
Well that makes more sense. However I've never seen a b/w vector blow all 4 transistors, so that's not too common.

Test the bridge rectifier also with your DMM (google if necessary). Sounds like there could be a power issue. You can test quickly for shorts, but should also check for the correct voltage drops across each of the pairs of terminals.
 
Well that makes more sense. However I've never seen a b/w vector blow all 4 transistors, so that's not too common.

Test the bridge rectifier also with your DMM (google if necessary). Sounds like there could be a power issue. You can test quickly for shorts, but should also check for the correct voltage drops across each of the pairs of terminals.

OK. Check your inbox, I sent you a question. You're the man, btw
 
(Replying to your PM here, for anyone else following).

Yep, the Buffet vid you PM'ed is basically it.

Generally speaking, for any transistor, and your DMM in diode test mode, you should measure between 0.5-0.7V between two pairs of terminals in one direction (relative to the base pin), and open circuit in the opposite direction. Also, if any two terminals are shorted, it's definitely bad. (Test all combinations of the 3 pins.)

When testing them in-circuit (e.g., the ones on the deflection board), it gets a little more complicated, as the other components around the transistor can affect the measurement. Sometimes this will cause one of the B-C or B-E measurements to be a little low (0.2-0.3V). But the rule still stands, in that you should see voltage drops between both base and collector and base and emitter (in one direction), and NOT both cases in the opposite direction. (You may see one of them be 0.2-0.3V in the opposite direction, but not both of them, as the other should measure open-circuit, i.e., 'OL').

It sounds more complicated than it is. Wish I had a vid to explain, but once you figure it out it'll make sense, and you can check all of the transistors pretty quickly.
 
(Replying to your PM here, for anyone else following).

Yep, the Buffet vid you PM'ed is basically it.

Generally speaking, for any transistor, and your DMM in diode test mode, you should measure between 0.5-0.7V between two pairs of terminals in one direction (relative to the base pin), and open circuit in the opposite direction. Also, if any two terminals are shorted, it's definitely bad. (Test all combinations of the 3 pins.)

When testing them in-circuit (e.g., the ones on the deflection board), it gets a little more complicated, as the other components around the transistor can affect the measurement. Sometimes this will cause one of the B-C or B-E measurements to be a little low (0.2-0.3V). But the rule still stands, in that you should see voltage drops between both base and collector and base and emitter (in one direction), and NOT both cases in the opposite direction. (You may see one of them be 0.2-0.3V in the opposite direction, but not both of them, as the other should measure open-circuit, i.e., 'OL').

It sounds more complicated than it is. Wish I had a vid to explain, but once you figure it out it'll make sense, and you can check all of the transistors pretty quickly.

OK. I will try to figure out stuff going on on the deflection board. I know that 3 of the 4 on the frame are no bueno.
 
(Replying to your PM here, for anyone else following).

Yep, the Buffet vid you PM'ed is basically it.

Generally speaking, for any transistor, and your DMM in diode test mode, you should measure between 0.5-0.7V between two pairs of terminals in one direction (relative to the base pin), and open circuit in the opposite direction. Also, if any two terminals are shorted, it's definitely bad. (Test all combinations of the 3 pins.)

When testing them in-circuit (e.g., the ones on the deflection board), it gets a little more complicated, as the other components around the transistor can affect the measurement. Sometimes this will cause one of the B-C or B-E measurements to be a little low (0.2-0.3V). But the rule still stands, in that you should see voltage drops between both base and collector and base and emitter (in one direction), and NOT both cases in the opposite direction. (You may see one of them be 0.2-0.3V in the opposite direction, but not both of them, as the other should measure open-circuit, i.e., 'OL').

It sounds more complicated than it is. Wish I had a vid to explain, but once you figure it out it'll make sense, and you can check all of the transistors pretty quickly.

OK, lets dumb this WAY down for me lol.

Lets say I start with Red lead on base, am I looking for for 0.5-0.7 on both the C and E? or just one of them and the other OL.
 
Ok, hopefully this explains it more clearly:

- Put one lead on base (black or red, doesn't matter which you start with)
- Look for 0.5-0.7V drops to *both* C and E, using other lead. (Note one of them might be low, 0.2-0.3V).
- If you don't get BOTH drops, put other color lead on base, and try again. You should *definitely* see two drops with the other color lead on the base in this case (i.e., going in the opposite direction).
- If you DID get both drops the first time, put the other color on the base, and verify that you DON'T get *both* drops in the opposite direction. (You may see one of them be 0.5-0.7, or 0.2-0.3, but at least ONE of them should be OL).


Sometimes when you see the lower 0.2-0.3V drops, you usually see them in both directions, which is normal (when testing the transistor in-circuit. Out of circuit they should always be 0.5-0.7V, and only in one direction).

Worst case, if there's any doubt, desolder the part, and test it out of circuit (in which case Buffet's video applies).


So, to sum it up, for testing in-circuit, you want to see drops to BOTH C and E (from B) in one direction, and OL in AT LEAST one direction going the opposite direction (i.e., when you reverse the polarity of the leads). And you don't want to see shorts between any of the 3 terminals. If any of the above are not true, suspect the part is bad, desolder it, and doublecheck (as there are some cases, not on this deflection board though, where you can see exceptions to the above, if there are things near the transistor like inductors or low-ohm resistors, which can look like shorts, etc).

Make sense?
 
Ok, hopefully this explains it more clearly:

- Put one lead on base (black or red, doesn't matter which you start with)
- Look for 0.5-0.7V drops to *both* C and E, using other lead. (Note one of them might be low, 0.2-0.3V).
- If you don't get BOTH drops, put other color lead on base, and try again. You should *definitely* see two drops with the other color lead on the base in this case (i.e., going in the opposite direction).
- If you DID get both drops the first time, put the other color on the base, and verify that you DON'T get *both* drops in the opposite direction. (You may see one of them be 0.5-0.7, or 0.2-0.3, but at least ONE of them should be OL).


Sometimes when you see the lower 0.2-0.3V drops, you usually see them in both directions, which is normal (when testing the transistor in-circuit. Out of circuit they should always be 0.5-0.7V, and only in one direction).

Worst case, if there's any doubt, desolder the part, and test it out of circuit (in which case Buffet's video applies).


So, to sum it up, for testing in-circuit, you want to see drops to BOTH C and E (from B) in one direction, and OL in AT LEAST one direction going the opposite direction (i.e., when you reverse the polarity of the leads). And you don't want to see shorts between any of the 3 terminals. If any of the above are not true, suspect the part is bad, desolder it, and doublecheck (as there are some cases, not on this deflection board though, where you can see exceptions to the above, if there are things near the transistor like inductors or low-ohm resistors, which can look like shorts, etc).

Make sense?


100% absolutely makes sense. Almost done testing them all, and everything has passed that so far
 
Cool.

Also, for the bridge rectifier, it is basically four diodes in a diamond pattern. So, you should see 0.5-0.7V drops between adjacent terminals in one direction, but OL in the other direction. If any adjacent terminals are OL both ways, or shorted in any direction, then the BR is bad.
 
??????????????

If this is a BZ upright, the monitor comes out the rear of the game.
To analyze it correctly, the OP should remove the assembly and test on the bench.



Sorry, my bad. My BZ is an open-face model, so the monitor comes out the front.

I forgot we were dealing with a standard BZ here.
 
OK, way too long before I was able to get back into this. The true love of pinball came up and I got pulled away...but here's what I did and what I have.

1. replaced frame transistors
2. did a cap kit on deflection board and HV PCB. I did not do the filter caps on the
deflection board, I tried but they didnt want to come out. Little recessed holes
packed with solder?

I hooked it all back up and turned it on and I'm getting what I think is a partial image. While I play a game the crosshair flickers in and out and I think the entire image may be flickering in and out? Not sure.

I've linked a video of some "exciting" gameplay.

https://www.youtube.com/watch?v=sDjwdLpEaYo
 
Adjust your brightness and contrast on the deflection board. They're too low.

Also, it isn't usually necessary to replace the filter caps. But you need a hot iron or decent desoldering gun to get them out, as the ground and power planes they're soldered to end up sinking a lot of heat. You just need to get enough heat in there to compensate.
 
Last edited:
Adjust your brightness and contrast on the deflection board. They're too low.

Also, it isn't usually necessary to replace the filter caps. But you need a hot iron or decent desoldering gun to get them out, as the ground and power planes they're soldered to end up sinking a lot of heat. You just need to get enough heat in there to compensate.

ok, done. Much brighter, looks better.

I'm not seeing any enemies and I'm getting a reset issue I believe.

https://www.youtube.com/watch?v=8Yd7LT7MP7E
 
Power the cab on with the test mode switch enabled, and post what the screen shows.

Also, make sure you have the contrast all the way up, and adjust the brightness just low enough so the retrace lines between the objects just barely disappear. Just so we know we're seeing everything that's being drawn, as there can be brightness-related issues where the objects are there, but just not bright enough, vs other issues where they aren't there at all.

Actually, you can also try turning the brightness up so the retrace lines ARE there (just barely, not all the way up), and see if you see any enemies or other objects.
 
Power the cab on with the test mode switch enabled, and post what the screen shows.

Also, make sure you have the contrast all the way up, and adjust the brightness just low enough so the retrace lines between the objects just barely disappear. Just so we know we're seeing everything that's being drawn, as there can be brightness-related issues where the objects are there, but just not bright enough, vs other issues where they aren't there at all.

Actually, you can also try turning the brightness up so the retrace lines ARE there (just barely, not all the way up), and see if you see any enemies or other objects.

OK. I cranked the brightness up higher and for maybe 30 seconds I was able to see enemies and other objects, etc. The game reset and afterward they were gone again. while they were there there were spastic lines that would show across the screen, like a "flinching" sort of appearance, appear and disappear quickly.

Right now I'm back to getting nothing, playing blind. I'm fairly certain I could keep turning it on and off and I'd get an image again but I'm not sure.

Regarding a test switch I've attached a photo. Is that what I'm looking at there or is it found on the board? Assuming it would not be on the board. This guy is in but it's not wired up. I have found two floating wires that would appear to have been connected to this at one point in time.

https://farm1.staticflickr.com/783/40814805011_b9e33ea187_c.jpg
 
The test switch is normally inside the coin door (i.e., on the coin door).

Download and read the manual for other details, as well as how to decode what the test screen tells you.

You may have other game board issues. Do the usual, check voltages, reflow the interconnect header pins, clean and reseat the ROMs, etc, in addition to figuring out what the test screen says.
 
Last edited:
yeah the issue is I don't have a coin door.

when this thing came to me it was without.


Get or make some kind of test lead (ideally with a grabber clip on one end, i.e., something small), and connect one end to any GND test point on the main board, and hook the other end to either side of resistor R133 on the main board. That will simulate the test switch being closed. Then power on the cab.

Your other option is to figure out which pin in the coin door connector goes to pin 7 of the main edge connector, and ground that, as that's the self-test signal's wire (which connects to R133).
 
Get or make some kind of test lead (ideally with a grabber clip on one end, i.e., something small), and connect one end to any GND test point on the main board, and hook the other end to either side of resistor R133 on the main board. That will simulate the test switch being closed. Then power on the cab.

Your other option is to figure out which pin in the coin door connector goes to pin 7 of the main edge connector, and ground that, as that's the self-test signal's wire (which connects to R133).

Any significance to the LED on the deflection board blinking? When it blinks there's a little bit of a buzz or a hum sound and the image blips out on the screen.
 
Back
Top Bottom