Cinematronics BW vector question

modessitt

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Ok, so I'm working on a 13" Keltron from a Star Castle. The monitor was dead, was partially worked on by someone else, and came to me non-working.

Upon power up it smoke R130. I found Q106 to be bad, and further inspection showed that Q106 was not the proper part. I replaced Q106 and R130, powered up and immediately started smoking R130 again (although Q106 did not blow this time). I found that if I unplugged the vertical amplifier plug, then R130 would not smoke. Checked and found a short on the 2N3716 for that circuit. Replaced it and R130, and now R130 does not start smoking on power up.

However, R118 smokes instead as soon as power is applied. This wasn't burning up before.

I've already replaced all the 2N5320's and 2N5322's. I've checked all the 2N3716's and 2N3792's, but they measure fine, and I've replaced the rubber insulators with new mica insulators.

I was reading the Cinematronics Monitor FAQ, and it mentions replacing all the 47-ohm resistors with 5W versions. I'm wondering whether this would resolve my issue, as the 5W would handle the load (and not burn up), or is there likely another problem elsewhere? I've checked all the diodes and transistors in the circuit, and can't find anything obvious.

Also, I've been hooking up all the connectors during testing except the ribbon cable. I'm not sure if that would have anything to do with it, either.

Anybody got any bright ideas?
 
Except the ribbon cable? the main ribbon cable from the monitor to the pcb? I beleive that actually controls voltages on the monitor board. Im almost positive I have read not to power the monitor up with out that hooked up.
 
"Never power up the monitor board with the ribbon cable (leading to the CCPU board)
disconnected. If you do this, there are undefined values going into the digital-to-analog"

from the monitor faq if that helps
 
If you are burning resistors up, you still have something shorted. Upgrading to the 5 watts won't help. What circuit is R118 on?

You may have done more damage when you powered it up without the vertical Amps connected.

Check the 3 (I think) tantualum caps. They frequently burn up when you burn up the 47 ohm resistors. Most times it's pretty obvious that they are toasted but every once and a while they short and look fine.
 
Dunno if I mentioned I found one of the .18-ohm 3W choke resistors shorted there, too. Got them coming in soon, so hopefully this will fix the monitor....
 
Does the board work? You shouldn't power up the monitor without the board working, or without the ribbon cable hooked up, because the DACs will drive whatever signal it sees, which can be bad if the board is bad, or completely undefined if the inputs are floating. That could definitely be blowing stuff.

I don't know, but you may be able to get away with it by unhooking the yoke (and neck to avoid burn-in), and maybe the output transistors. It seems like it'd be better to just give it a good signal though, and listen for deflection.

DogP
 
Well, once I get the last pieces, I'll hook up the ribbon cable this time and see if it still burns up parts...
 
Well, I got my parts in and replaced the .18-ohm 3w resisistors. Also got new 2N3716's and 2N3792's. Found that one pair was in wrong (by checking against the wire colors below). Everything is now in properly.

Powered it up with ribbon cable connected and popped a breaker. reset and tried again, this time the fuse blew.

I guess I should try powering up without the monitor connected to verify that the issue is with the monitor? What is my next step?
 
hey mod

i know this is a seriously old post, but what resolution did you find for this? i find myself in the exact same spot.

here is the weird thing, when I got this game it was totaled. a rock ola version cocktail. armor attack.

i rebuild the powersupply, the sound board, and the ccpu and got the game playing blind. that took bloody forever.

now the monitor is popping breakers like crazy. see pics of the monitor board, someone really hacked this up , however, i have cleaned all of this up, there were diodes in backwards, resistors totally out of spec, a few of the 3906's were shot, I did the tantulum upgrades, i upgraded the 4003 diodes to 4004's, ive done it all.

but the breakers still pop.

so wondering if you recall what your solution was, or if you have any advice. i have been all over this bloody thing and I cant find anything wrong.,
 
Our Armor Attack monitor is popping breakers.

If we turn the game on with the monitor hooked up and the yoke socket removed, it does not.

We checked voltages on the yoke inputs, and found one pegged to -25VDC, the other was bouncing around.

So we took a logic probe from the DACs through both deflection circuits, and found Q204 was bad. Should receive a replacement in the mail today.

We seem to be pretty much at the Symptom Summary described in the Cinematronics Vector Monitor Repair Guide on page 41 (Symptom Summary: Discrete HV monitor stays up for about 10 seconds, with deflection chatter, no picture. Then the -25V breaker pops (then shortly after, the +25V breaker).
 
We seem to be pretty much at the Symptom Summary described in the Cinematronics Vector Monitor Repair Guide on page 41 (Symptom Summary: Discrete HV monitor stays up for about 10 seconds, with deflection chatter, no picture. Then the -25V breaker pops (then shortly after, the +25V breaker).

Did this new DAC solve your problem? I'm just digging in my star castle with this same problem on that page, but there seems to be a million ways to fix it. I have a NOS flyback coming from arcadeshop and will start from there. Otherwise my game plays blind with the deflection board unplugged.
 
Did this new DAC solve your problem? I'm just digging in my star castle with this same problem on that page, but there seems to be a million ways to fix it. I have a NOS flyback coming from arcadeshop and will start from there. Otherwise my game plays blind with the deflection board unplugged.

Did you check all the transistors? Both the chassis and the small drivers on the PCB. This typically opens the breakers.
 
Did you check all the transistors? Both the chassis and the small drivers on the PCB. This typically opens the breakers.

None of this yet, I am planning to replace everything on Billtronix's list. Some things have dissapeared from sites, so locating everything has proven to be quite the undertaking.

You wouldn't know if the breakers can be replaced with something? Mine seem very stiff to reset when pushing in/out.
 
Humm, maybe your breakers are the issue? Do you know the CCPU is good?

https://groups.google.com/forum/#!topic/rec.games.video.arcade.collecting/pAGUCTccklE

" ... As for the breakers popping, what I have learned of the old
Cinematronics power supplies is this is most likely NOT an issue with
the CPU board but rather an issue with the breakers themselves. With
age, the breakers get oxidation on their contacts and don't provide
true 3amp coverage. If memory serves, a post some years ago recommended
replacing the breakers with a newer model in roughly the same form factor
and the problem of them popping went away.


Doesn't mean you don't have CPU problems just that the breakers popping
are most likely due to the age of the breakers rather than any issues
with the CPU ... "
 
Did this new DAC solve your problem? I'm just digging in my star castle with this same problem on that page, but there seems to be a million ways to fix it. I have a NOS flyback coming from arcadeshop and will start from there. Otherwise my game plays blind with the deflection board unplugged.

In our case, it was not the DACs, but Q204. We had previously been able to borrow an oscilloscope and validate that up to and including the DACs, the output was correct. We used a logic probe, one by one on each of the transistors to in effect listen to the deflection chatter, and the first pair that sounded different in that circuit was Q104/Q204. Pulled Q204 out and tested it and determined the transistor was bad.

Once we replaced Q204, we just had an intermittent collapse problem, which was traced to one of the molex connectors that attached the frame mounted transistors to the main monitor PCB, so that was an easy fix.

This was after replacing the flyback with the NOS from ArcadeShop (visible evidence of failure, plus no +90V coming out led us to that), replacing much of the spot killer circuit, as well as (if I recall correctly) IC7. Early on we were able to get a picture to show up by shorting Q2 I think it is, which bypasses the spot killer.
 
In our case, it was not the DACs, but Q204. We had previously been able to borrow an oscilloscope and validate that up to and including the DACs, the output was correct. We used a logic probe, one by one on each of the transistors to in effect listen to the deflection chatter, and the first pair that sounded different in that circuit was Q104/Q204. Pulled Q204 out and tested it and determined the transistor was bad.

Once we replaced Q204, we just had an intermittent collapse problem, which was traced to one of the molex connectors that attached the frame mounted transistors to the main monitor PCB, so that was an easy fix.

This was after replacing the flyback with the NOS from ArcadeShop (visible evidence of failure, plus no +90V coming out led us to that), replacing much of the spot killer circuit, as well as (if I recall correctly) IC7. Early on we were able to get a picture to show up by shorting Q2 I think it is, which bypasses the spot killer.

Thanks, I plan to replace all that I can on this deflection board minus the DAC's and other IC's. Hopefully that will rule out a lot of transistor failures.

Humm, maybe your breakers are the issue? Do you know the CCPU is good?
Well the game plays blind just fine when power to the deflection board is pulled. Only brought up the breakers because of how they feel when resetting, but they are apparently breaking just fine. :)
 
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