Mrs. Pacman help

[P-feif]

Replaced the speaker. Still the same problem. I did measure the voltages at the two big filter caps on the PCB and it was 8.2 volts. Sounds a little high to me. I'm going to go dig on the web but shouldn't that either be 7 volts or 5 volts? I don't know that that's my sound issue but it's still something that I need to look into. At any rate I still have a sound issue. Please see my video that I posted above.

[P-feif]

Just read this on the lawnmowerman web page....


Next read DC voltage from ground to the top end of R52,  about 12 Volts DC.  Missing voltage here would indicate open R52.

Next read DC voltage from ground to BASE of transistor on Heat Sink, should be about 5 VDC.

Low Voltage 2~3 VDC when measured at C2 or C3.  Resistor R53  4 Ohm 10 Watt gets warm.  Measured Voltage from Ground to the Base pin of  Q6 ( D44MV4 on the big heat sink, may also be a TIP 31 or ECG 377) Shows ~ 8 VDC.

Replace D44VM4.  Be sure to install mica insulation & plastic sleeve on the the bolt too.

~ Note the pins on Q6 are marked on the board or refering to the above picture top to bottom

B) ase
C) ollector
E) mitter


Looks like a transistor? I'm guessing it regulates voltage some how?

[P-feif]

Ok I've done a little measuring with my multimeter and here's what I've found. Voltage at C2 and C3 is 8.2 volts, should be 5 volts. Volts at R52 either 15.8 and/or 16.3 depending on wich end is considered the top end of the resister (lawnmower man web page says to measure it at the top end of the resistor), should be 12. Voltage at the base leg of the voltage regulator is 5.6, should be 5. Resistor R53 gets hot to the touch.

So what do you guys think? Change the voltage regulator? The lawnmower man web sight says that you may find a TIP31 transistor in place of the regulator (original is a D44MV4 3 pin voltage regulator). So can I replace it with a TIP31 transistor? Or should I track down a 5 volt regulator equivalent to the original.

[thegleek]

Ok I've done a little measuring with my multimeter and here's what I've found. Voltage at C2 and C3 is 8.2 volts, should be 5 volts. Volts at R52 either 15.8 and/or 16.3 depending on wich end is considered the top end of the resister (lawnmower man web page says to measure it at the top end of the resistor), should be 12. Voltage at the base leg of the voltage regulator is 5.6, should be 5. Resistor R53 gets hot to the touch.

So what do you guys think? Change the voltage regulator? The lawnmower man web sight says that you may find a TIP31 transistor in place of the regulator (original is a D44MV4 3 pin voltage regulator). So can I replace it with a TIP31 transistor? Or should I track down a 5 volt regulator equivalent to the original.

Hah! Wow! I'm having voltage issues with my Ms Pacman too! Maybe one day we can set something up to compare notes on fix both our games! We have an arcade group (small - 3 people now) that meets after 6pm on Monday's. But anyways, lemme know your thoughts and obtain permission from homeowner to see if this can be arranged...

[P-feif]

Well I work afternoons so it gets pretty hard to do things like that but I would love to talk arcade games with you guys sometime.

For now look on the lawnmowerman web site. They have good information on the pacman and ms pacman games.


http://lawnmowerman.rotheblog.com/

[thegleek]

Well I work afternoons so it gets pretty hard to do things like that but I would love to talk arcade games with you guys sometime.

For now look on the lawnmowerman web site. They have good information on the pacman and ms pacman games.

http://lawnmowerman.rotheblog.com/

Hah! I've been on that site for hours & hours. Great reference! We also started a local (to us at least) blog with our adventures: http://gameaholix.com/

[iankellogg]

Ok I've done a little measuring with my multimeter and here's what I've found. Voltage at C2 and C3 is 8.2 volts, should be 5 volts. Volts at R52 either 15.8 and/or 16.3 depending on wich end is considered the top end of the resister (lawnmower man web page says to measure it at the top end of the resistor), should be 12. Voltage at the base leg of the voltage regulator is 5.6, should be 5. Resistor R53 gets hot to the touch.

So what do you guys think? Change the voltage regulator? The lawnmower man web sight says that you may find a TIP31 transistor in place of the regulator (original is a D44MV4 3 pin voltage regulator). So can I replace it with a TIP31 transistor? Or should I track down a 5 volt regulator equivalent to the original.

IF the big resistor in the upper right hand corner is getting really hot then your voltage regulator is dead and needs replaced.

Edit. By voltage regulator I mean the 3 pin transistor that is on the heat sink. The voltage regulator is a 4 pin device below the heatsink. It most likely does NOT need replacing.

[P-feif]

Ok I've done a little measuring with my multimeter and here's what I've found. Voltage at C2 and C3 is 8.2 volts, should be 5 volts. Volts at R52 either 15.8 and/or 16.3 depending on wich end is considered the top end of the resister (lawnmower man web page says to measure it at the top end of the resistor), should be 12. Voltage at the base leg of the voltage regulator is 5.6, should be 5. Resistor R53 gets hot to the touch.

So what do you guys think? Change the voltage regulator? The lawnmower man web sight says that you may find a TIP31 transistor in place of the regulator (original is a D44MV4 3 pin voltage regulator). So can I replace it with a TIP31 transistor? Or should I track down a 5 volt regulator equivalent to the original.

IF the big resistor in the upper right hand corner is getting really hot then your voltage regulator is dead and needs replaced.

Edit. By voltage regulator I mean the 3 pin transistor that is on the heat sink. The voltage regulator is a 4 pin device below the heatsink. It most likely does NOT need replacing.

Thanks Ian. I did see the 4 pin and knew that it was not a transistor. So the BIG heat sink with the 3 pin transistor really is a transistor? Will a TIP31C work, I have one from Bob Roberts, but was going to look deaper into it. I can replace it now if the TIP31C is o.k. to use.

By the way did you mean the big resistor in the upper left hand corner? Right above the transister on the big heat sink? That's the one that's getting hot, really hot.

[iankellogg]

I think a tip is fine replacement.  Yes I am talking about the resistor above the heatsink.

[P-feif]

Cool! I'll try to get it replaced in the next few days. Thanks Ian!!! ;)

[P-feif]

Alright I replaced that transister on the big heat sink with a TIP31C. Got it done this morning and now...... nothing, no change. All my voltages are still screwed up (see my post above) and the sound is still messed up. What do you think Ian? The 4 pin volt regulator???

I'll say this, I don't think there's much left to replace.

[iankellogg]

thats all i can think of left.

[P-feif]

Alreighty then! I'll track one down and see what happens. I suppose that one of the ceramic resisters could be weak but to be honest I haven't studied the prints enough to know how power is flowing through the circuite so I really don't know how those resisters contribute. So the voltage regulator it is. I'll keep you up on things. Again thanks for your help Ian.

[iankellogg]

The resistor should never get hot.  The only reason it is there is to keep the board from blowing up when the regulator fails.

[P-feif]

Hmmmm, so I probably shouldn't turn it on much for the moment?