Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: HaRuMaN on February 19, 2010, 06:10:29 pm
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I just got around to pulling the deflection PCB out of my Battlezone, and I noticed that someone has done something to it. Looks like they cut off R100 and R101 and just bridged each of those with a thick wire.
Anyone know what resistors those are supposed to be? I'm going blind looking at a schematic...
Also... can the board be run as-is (missing R100 and R101)?
Also. How can you tell if the bridge rectifier is bad or not? I have a new one, regardless.
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Resistors removed - common field modification, it's fine.
Rectifier - standard diode test x 4
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How do you do a diode test? I'm guessing just make sure current flows only one way, and not the other?
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diode test = set volt meter to diode test
sick probes on either side of diode (you may have to remove one side of diode from the board to get a good result)
should be a reading one direction - around 0.5 volts
reversing the leads should result in nothing
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Oh, duh. I have a HP 34401A Multmeter. I just now noticed the Diode test setting (it's Cont + Shift), lol.
Looks like this:
(http://www.harlanlabs.com/34401a.jpg)
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Ok, so the bridge rectifier was bad (no big surprise, it kept blowing fuses).
Put the board back in, the red LED is still on (spot killer?)...
But now, I get a green dot in the middle of the screen, with a horizontal green line through the middle. As I move the tank around, it seems like I can see changes in the horizontal line.
What do you call this? Horizontal collapse?
What should I do next? Help out a vector noob! :D :cheers:
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Vertical Collapse (Y axis)
Don't run it very long like that, you'll burn a dot and line into your screen.
BTW - Which monitor do you have?
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I only ran it like that for like a minute...
It's a Battlezone upright, were there more than one monitor that came with it?
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Found this:
1. Insufficient width or height:
A. Horizontal line (due to "Y" amplifier defection).
· Bad "Y" amplifier output transistors.
· Blown "Y" amplifier fuse.
· Open fusible resistor in the "Y" amplifier.
· Yoke pins not making good contact (very common).
· Bad yoke.
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It's a Battlezone upright, were there more than one monitor that came with it?
Well, it's a B/W vector.... there's only a couple I could guess it to be..... but I don't like to "guess".
And it's hard to point you at specific things to look at on the deflection pcb without knowing which monitor it is. i.e. We can't say "check Q103" if we have no idea if we're looking at the same chassis as you have.
But IF I did have to guess... I'd say it was an Electrohome G05-802. ;)
I'd start by downloading the monitor manual, checking voltages at the harness connection, and checking all the 600 series components. (R6xx, Q6xx, D6xx, etc)
And of course ANY and ALL possibly bad/questionable solder joints anywhere on the deflection pcb.
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Gotcha. I'll double-check the monitor to see what it is. I was assuming, since it is an upright BZ, that it is a G02.
The deflection board definitely is a G02, I downloaded a schematic and used that to replace all the fuses with proper values.
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Anyone know of a source for Q606, Q607?
On the schematic it is a MPSU07 which appears to be obsolete (Motorola part). These are the transistors with the big heat sinks, btw.
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Looks like RCA SK3199 is compatible, also obsolete... :badmood:
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Nevermind, Bob Roberts has them, lol. :applaud:
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Well, replaced the MPSU07's, spot killer LED is still on, and F600 keeps blowing... any ideas? :banghead:
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F600 is for the Y axis amplifier. Q608,609.
http://arcarc.xmission.com/PDF_Monitors/Atari%20Monitor%20TM-151%20Issue%202%20Electrohome%20G05-802%20G05-805%20Monochrome%20XY.pdf (http://arcarc.xmission.com/PDF_Monitors/Atari%20Monitor%20TM-151%20Issue%202%20Electrohome%20G05-802%20G05-805%20Monochrome%20XY.pdf)
Page 11.....bottom left.
You need to replace that pair, and check all the components in that circuit. They are basically just a rudimentary audio pwr amp, so the same rules apply. If an output device shorts, the driver and bias components may well be taken out with it.
For the outputs, I would use something beefier. I suggest the MJ15023/MJ15024 pairs. I'm not so sure the 3716/3792 is even in production anymore, so the likelyhood of buying fakes is increased.
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Forgot to mention, Q608 and 609 are large metal case to-3 transistors mounted to the frame of the monitor.
http://www.zinfer.com/arcadepage/asteroids/12122002/DSCF0003.jpg (http://www.zinfer.com/arcadepage/asteroids/12122002/DSCF0003.jpg)
You'll have to trace wires back from the appropriate pins of the connector to identify which pair is causing the problems.
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Awesome, thanks! I have those parts already, just haven't installed them. I've been replacing known bad parts, and working my way back. (While burning up a bunch of fuses, lol).
:cheers:
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You always work from def amp outputs back toward the input on vector monitors. From most likely to fail (output transistors) to least likely...
When you replace those output transistors, make sure you use mica insulating spacers (and fresh heatsink goop) between the transistor and the frame. The transistor mounting plate *cannot* contact the monitor frame....
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Thanks for the tips. I'm definitely a vector n00b, and any help is appreciated.
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You always work from def amp outputs back toward the input on vector monitors. From most likely to fail (output transistors) to least likely...
When you replace those output transistors, make sure you use mica insulating spacers (and fresh heatsink goop) between the transistor and the frame. The transistor mounting plate *cannot* contact the monitor frame....
A couple of weeks ago I was working on my Red Baron with the monitor on the ground behind the cabinet playing video. I dropped a screwdriver and it briefly shorted an output tranny to the frame. The spark was enough to shoot the screwdriver over the edge of the monitor and a foot away. Nice big yellow CRACK spark. Luckily it didn't fry the transistor but man did that get the point home. ;D
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No that won't hurt the transistor, but I'm s'prised the fuse for that voltage rail didn't pop.....
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Looks like I'm going to have to pull the monitor to get to those transistors. :banghead: I was hoping to avoid that. Oh well...
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Replaced the case mounted transistors, F600 keeps blowing... :badmood:
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It's actually a WGV2000, btw...
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Talkin' to myself and feeling old...
Guess I'm going to recap, go through every 6xx component, and hope for the best.
Anyone know how to test if the case-mounted transistors are good?
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quick and dirty is to check for a short between either leg and the case. if there is a low resistance reading then it's toast.
the better test would be to use a B&K transistor tester. but even that's not fail proof, as often with high voltage transistors, they will test good with the low voltages used during testing but fail at high voltage.
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For the outputs, I would use something beefier. I suggest the MJ15023/MJ15024 pairs. I'm not so sure the 3716/3792 is even in production anymore, so the likelyhood of buying fakes is increased.
Which one replaces which?
MJ15023 = ?
MJ15024 = ?
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If the output device shorts, driver and bias components may be removed with it.