Asteroids pcb

necroscope

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I just got an asteroids cab and the pcb has a missing transistor at location VR2 would somebody be kind enough to tell me what transistor is supposed to be there as the schematics i have found on the net are as clear as mud to me and i am having trouble understanding them..Thanks.
 
I just got an asteroids cab and the pcb has a missing transistor at location VR2 would somebody be kind enough to tell me what transistor is supposed to be there as the schematics i have found on the net are as clear as mud to me and i am having trouble understanding them..Thanks.

I am not so sure that is a transistor the VR would suggest that it is a Variable Resistor and usually used on audio adjustment or a gain by the TL082 for the x output. I don't own one of them critters yet so wait for somebody that does. I just gave a quick glance at the schematic.

I guess it could be a voltage regulator also....Post a pic of the board it is on and I can help you better as I don't have a board here to look at. Since this is in the cab you have the power board that could have that part on it.

Is the missing part on the pcb of the game or on the power board?

What is the value or numbers on VR1?
 
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Thanks for having a look mate,it has 3 legs so i thought it was a transistor i'm a noob at pcb's but am learning as i go...the numbers are MC7812CT and below that is QQ7944
 
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That is a +12 volt regulator.

http://www.alldatasheet.com/datasheet-pdf/pdf/4497/motorola/mc7812ct.html

Most parts stores will still carry them. Is that the part you need or is that the value for VR1? Be sure as you don't want to put a 12 volt regulator where a 5 volt should be.

That is the part at VR1,Just found it it,looks like VR2 is supposed to be a 7915CT did a search and came up with a MC7915CT, 1 Amp, 15 Volt, Negative Voltage Regulator,hoping someone can confirm this is the missing part before i buy a replacement.thanks.
 
That is the part at VR1,Just found it it,looks like VR2 is supposed to be a 7915CT did a search and came up with a MC7915CT, 1 Amp, 15 Volt, Negative Voltage Regulator,hoping someone can confirm this is the missing part before i buy a replacement.thanks.

might just get an assortment of them regulators as you can't have enough it seems. Cheers.
 
Asteroids uses four voltage regulators, VR1 is a 7812 supplying +12v to the audio section, and the other three supplying required voltage to the analog output section:
VR2 is a 7915 supplying -8.2v and -15v
VR3 is a 7805 supplying +5v
VR4 is a 7815 supplying +8.2v and +15v
No picture without all three.

Bob Roberts sells them individually or in a kit of 16 popular values.
http://orderfrombob.com/#vr

I hope that's the only problem.
 
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