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NBA Jam Jamma Arcade Machine Help
Question from Jordan: Hi,
Let me start off by saying that I am currently embarking on my first restoration of an arcade machine. I have watched many of your YouTube videos and have read a lot of information on your website and it has been really helpful to me. However, I am looking for some direct help because I am seemingly at an impasse which probably has a very easy solution for the pros.
I recently purchased an original NBA Jam jamma machine that was said to only require a new monitor.
I have a spare LCD monitor so my plan is to convert the it to VGA using the “CGA/EGA/YUV to VGA Arcade HD-Converter PCB” found here. http://www.jammaboards.com/store/cga-ega-yuv-to-vga-arcade-hd-converter-pcb-gbs-8220-gbs-8220.html#product249
After not having much luck so far, I am thinking that I may potentially have a bad power supply. This is what my power supply set up looks like.
When using a multimeter to check the voltage the only place that I have been able to find anything is on both sides of the AC filter which is running about 120V on both sides. Other than that I can’t find anything. Could there be a switch somewhere I don’t know about? The guy I bought the cabinet from said “the pcb lights up when it the machine powers on.” I have not been able to achieve this.
Any advice you can give a newbie is greatly appreciated and thanks for the fantastic content on the website and videos.
Thanks again,
Jordan
1 answer
Response from Jonathan: Jordan,
First off, thanks for the kind words about our web site. We’re glad you find the content helpful.
Yes, there could be a switch somewhere stopping the AC voltage from getting to the switching power supply. To troubleshoot this issue, try following the wires coming from the AC filter to their next destination. Many arcade cabinet have door switches that look like this:https://images10.newegg.com/NeweggImage/ProductImageCompressAll300/A0KR_1_20110916_11110093.jpg. These switches are designed to stop the flow of electricity whenever the arcade game back or front door is open. The good news is that you can activate these switches by either pushing them in and holding them in or by pulling them out. Of course, you could also have a standard on/off switch that needs to be turned on as well.
I know you mentioned that you might have a bad power supply in your email. This would only be the case if you were getting AC power to the power supply but no DC power supply was coming out of the power supply. You can always test this by putting your multimeter leads on the AC screws and seeing if you’re getting power to it. If do not get AC power at the power supply, you either have a break in your AC wiring or a switch that has not been turned on.
Hope that helps. Thank you for your question and good luck with your repair.
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