Curse you, Asteroids!

JuanUp

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So I'm cleaning up my machines and booting them up after being in storage for ages. I get to the Asteroids; open it up; clean everything inside and out; powered it up; played a few rounds, (awesome); put the back door on; went up front to play another game... no monitor and no marquee light. WTF?!

Man, this pisses me off something fierce... start buttons flash and plays blind. Opened up the back door. F100 & F101 dead on monitor. I already went through my Asteroids hazing and conquered this beast. This is bullshit.

I'm concerned it might be the power brick. Don't worry, Dokert... I already found the posts on power brick testing here:

http://forums.arcade-museum.com/showthread.php?t=121666

This is more of a rant than anything. There's tons of resource already on this forum. I'll test the power brick and go from there.

Annoyed,
Juan
 
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... no monitor and no marquee light. WTF?!

Man, this pisses me off something fierce... start buttons flash and plays blind. Opened up the back door. F100 & F101 dead on monitor. I already went through my Asteroids hazing and conquered this beast. This is bullshit.

The only fuse that should cause the maruqee light not to work is F1, which would cause everything to stop working. If it still plays blind, then the marquee going out must be a coincidence (or there's some wacky wiring in there...)
 
OK. I'll give the marquee a looking at as well. Thanks!

Juan

Edit: Wait... just to clarify. It's F100 and F101 on the monitor deflection board.
 
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OK. I'll give the marquee a looking at as well. Thanks!

Juan

Edit: Wait... just to clarify. It's F100 and F101 on the monitor deflection board.

Test DB100 (Bridge rectifier for the monitor) It will usually cause F100 and / or F101 to blow when it is bad. (Standard bridge test with power off)
 
The results are in...

Thanks, Dokert for the tip! Unfortunately, I have bad news on the power brick front. Here's the numbers:

Power
14.36VDC - should be 10.3VDC
14.38VDC - should be 10.3VDC
14.39VDC - should be 10.3VDC
37.8AC - should be 36.0VAC
7.15AC - should be 6.3VAC
45.3AC - should be 60.1VAC
49.1AC - should be 60.1VAC

ARII
5.62DC - should be 5.0VDC
5.62DC - should be 5.0VDC

Doesn't look good. :(

Juan

Edit: Also, I tryed to lower the voltage from the AR board and the pot is at its lowest setting.
 
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All within spec, except +5vdc

Thanks, Dokert for the tip! Unfortunately, I have bad news on the power brick front. Here's the numbers:

Power
14.36VDC - should be 10.3VDC
14.38VDC - should be 10.3VDC
14.39VDC - should be 10.3VDC
37.8AC - should be 36.0VAC
7.15AC - should be 6.3VAC
45.3AC - should be 60.1VAC
49.1AC - should be 60.1VAC

ARII
5.62DC - should be 5.0VDC
5.62DC - should be 5.0VDC

Doesn't look good. :(

Juan

Edit: Also, I tryed to lower the voltage from the AR board and the pot is at its lowest setting.
 
That is great news and thank you for your time, Dokert! I'll start troubleshooting the usual suspects this evening.

Juan

Edit: Note to self. I'm checking out the schematics for the ARII board and it's quite possible that I have a bad resistor at R7 and / or bad voltage regulator at Q1 for the +5 over voltage. However, I may be completely wrong. ;)
 
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That is great news and thank you for your time, Dokert! I'll start troubleshooting the usual suspects this evening.

Juan

Edit: Note to self. I'm checking out the schematics for the ARII board and it's quite possible that I have a bad resistor at R7 and / or bad voltage regulator at Q1 for the +5 over voltage. However, I may be completely wrong. ;)

Did you test the +5vdc with the board hooked up or disconnected?
 
Did you test the +5vdc with the board hooked up or disconnected?

I removed the 9-pin P7 connector from the ARII board when I initially tested the +5VDC. It was mentioned in your origional post that the reading can be as high as 7 or 8VDC since it is unregulated.

JuanUp said:
Edit: Note to self. I'm checking out the schematics for the ARII board and it's quite possible that I have a bad resistor at R7 and / or bad voltage regulator at Q1 for the +5 over voltage. However, I may be completely wrong.

Yeah, ignore that note to myself... Like you said, it's more likely I need to replace KBPC602 (DB100) on the regulator board. I tested it last night in-circuit and I'm getting around 1000 - 1200mV forward voltage drop on one or two of the diodes in that package. Now I'm no electronics expert, but I'm guessing that's bad. :)

Juan
 
I removed the 9-pin P7 connector from the ARII board when I initially tested the +5VDC. It was mentioned in your origional post that the reading can be as high as 7 or 8VDC since it is unregulated.



Yeah, ignore that note to myself... Like you said, it's more likely I need to replace KBPC602 (DB100) on the regulator board. I tested it last night in-circuit and I'm getting around 1000 - 1200mV forward voltage drop on one or two of the diodes in that package. Now I'm no electronics expert, but I'm guessing that's bad. :)

Juan

DB100 should read .400 - .600 on all 4 diodes, anything else and it is bad. The power brick usually won't blow the fuses that you have called out, but a bad DB100 sure will.
 
DB100 should read .400 - .600 on all 4 diodes, anything else and it is bad. The power brick usually won't blow the fuses that you have called out, but a bad DB100 sure will.

Yep... forward voltage drop is around 0.400 - 0.500. I have 2 diodes on the rectifier that have a REVERSE voltage drop of 1.000 - 1.200. I found a place that actually has KBPC602 General Instrument rectifiers in stock. I got a bunch of them... just in case. ;)

Juan
 
I pretty much rebuilt the entire regulator board for the G05 Monochrome X-Y "Quadrascan" Monitor. Here's what I changed out:

C102 - (yes, it's in the right way)
C103 - (yes, it's in the right way)
D100 - (yes, it's in the right way) MUST be tested out of circuit.
D101 - (yes, it's in the right way) MUST be tested out of circuit.
DB100 - (yes, it's in the right way) MUST be tested out of circuit.
R100 - MUST be tested out of circuit.
R101 - MUST be tested out of circuit.
Q100 - (there's only one way to put this in properly onto the heat sink) MUST be tested out of circuit.
Q101 - (there's only one way to put this in properly onto the heat sink) MUST be tested out of circuit.

G05_RegulatorBoard_PCBLayout.jpg


I'm assuming P100 is all input and P101 is all output on the regulator board. It just doesn't make any sense... unless, perhaps... the fuses aren't the right spec? All the voltages out of P5 on the power brick are good. Otherwise, I'm stumped.

I'll keep poking around.

Juan
 
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Re-flow the solder joints on the board, especially the connector plugs. I had a similar problem, re-flowed and then stopped blowing the fuses and started destroying asteroids again...

-Dave
 
I pretty much rebuilt the entire regulator board for the G05 Monochrome X-Y "Quadrascan" Monitor. Here's what I changed out:

C102 - (yes, it's in the right way)
C103 - (yes, it's in the right way)
D100 - (yes, it's in the right way) MUST be tested out of circuit.
D101 - (yes, it's in the right way) MUST be tested out of circuit.
DB100 - (yes, it's in the right way) MUST be tested out of circuit.
R100 - MUST be tested out of circuit.
R101 - MUST be tested out of circuit.

Q100 - (there's only one way to put this in properly onto the heat sink) MUST be tested out of circuit.
Q101 - (there's only one way to put this in properly onto the heat sink) MUST be tested out of circuit.

G05_RegulatorBoard_PCBLayout.jpg


I'm assuming P100 is all input and P101 is all output on the regulator board. It just doesn't make any sense... unless, perhaps... the fuses aren't the right spec? All the voltages out of P5 on the power brick are good. Otherwise, I'm stumped.

I'll keep poking around.

Juan

Nope

For clarification... this is an 801 from what I see.

Do you have an O-Scope available for you to use?
 
Yep, it is an Electrohome Electronics G05-801 and I do have an o-scope.

However, I do not get proper testing results that you highlighted unless I take those components out of circuit. There are reverse voltage drops on the bridge rectifier and transistors unless I remove them from the board, (to be honest, I don't know why since the traces of the bridge rectifier go to the fuse mounts... dead ends. A clue to my problem?) I have also tested this on another working G05-801 regulator board which I get the same results. I test going red to anode, black to cathode on each of the four diodes to test for voltage drop then reverse red to black to test for discontinuity. Maybe I'm wrong... every day's a school day. (Thinking about it now, should I have only tested from the + / - prongs on the bridge rectifier in circuit?)

Anyway, enough of my babble. Yes, I do have an o-scope and thanks so much for your time.

Juan
 
I don't see why the bridge wouldn't test properly in-circuit.
Are you doing the test properly? Randy Fromm shows how to do it here (testing starts about 2:30 in): http://www.youtube.com/user/randyfromm#p/u/44/JEk23-R7Pow

pinrepair.com has these instructions:

#1 Put the DMM on diode setting.
#2 Put the black lead of the DMM on the "+" (positive) terminal of the bridge.
#3 Put the red lead of the DMM on either AC bridge terminal. Between .4 and .6 volts should be seen. Switch the red DMM lead to the other AC bridge terminal, and again .4 to .6 volts should be seen.
#4 Put the red lead of the DMM on the "-" (negative) terminal of the bridge.
#5 Put the black lead of the DMM on either AC bridge terminal. Between .4 and .6 volts should be seen. Switch the black DMM lead to the other AC bridge terminal, and again .4 to .6 volts should be seen.

You should not be testing + to - or AC (~) to AC (the other ~). All of the tests are from one of the DC terminals to one of the AC terminals.
 
I don't see why the bridge wouldn't test properly in-circuit.
Are you doing the test properly? Randy Fromm shows how to do it here (testing starts about 2:30 in): http://www.youtube.com/user/randyfromm#p/u/44/JEk23-R7Pow

pinrepair.com has these instructions:

#1 Put the DMM on diode setting.
#2 Put the black lead of the DMM on the "+" (positive) terminal of the bridge.
#3 Put the red lead of the DMM on either AC bridge terminal. Between .4 and .6 volts should be seen. Switch the red DMM lead to the other AC bridge terminal, and again .4 to .6 volts should be seen.
#4 Put the red lead of the DMM on the "-" (negative) terminal of the bridge.
#5 Put the black lead of the DMM on either AC bridge terminal. Between .4 and .6 volts should be seen. Switch the black DMM lead to the other AC bridge terminal, and again .4 to .6 volts should be seen.

You should not be testing + to - or AC (~) to AC (the other ~). All of the tests are from one of the DC terminals to one of the AC terminals.

heh... yep, I tested it the same as that Randy Fromm video. However, notice that he's testing it out of circuit. I can understand that if a diode has gone bad, normally it will open or short circuit and will show up easily in a continuity test. However, I'd prefer to test both polarities to ensure there's no reverse voltage, (perhaps unnecessarily. I just want to be thorough).

Juan
 
OK, I looked at the schematic more closely. Looks like when you try to reverse bias any one of the bridge diodes, there is another DC path: thru R100, R101 and another of the bridge diodes (I can draw a diagram, if you want). This would appear to explain why you see an apparent diode reading when testing them in-circuit.

Now back to your problem... what is it again?
 
Darren is correct on testing DB100 in circuit, no need to test for reverse polarity.

Set your O-Scope up for X-Y operation and connect your leads to the X out on the board and the Y out on the board. You should see Asteroids attract mode on your O-Scope. This will verify that your board is putting out the proper signals for the monitor.
 
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