Author Topic: Games of Nevada GVP-7 help (Read 4310 times)

Kjtemp · « **on:** September 28, 2021, 09:57:18 PM »

Just picked up a Games of Nevada gvp-7. Looks like they are pretty rare unfortunately for me. Is there any resource on repairing these? Can't even find a manual or schematic. Monitor and bottom light comes on and that's it. I just got it today so thought I'd ask for advice first before tearing into it. Thank you 🙂

shortrackskater · « **Reply #1 on:** September 29, 2021, 08:10:47 AM »

I would check the "obvious" first. Power down and pull the MPU out (carefully) and check all the IC's for any bent legs and that the MPU itself was plugged in fully.
Please note I have read that some legs might be that way on purpose as that particular gate was not used.
And, of course check that all the IC's are seated well into the sockets.
Check every connector you see in all the wiring. Unplug and replug. Be careful - the plastic can be brittle.
Post a photo of the inside and of the MPU board please.

Kjtemp · « **Reply #2 on:** September 29, 2021, 09:57:00 AM »

I will get into it after work tonight and report what I find, thank you.

Kjtemp · « **Reply #3 on:** September 29, 2021, 07:47:57 PM »

Here are some pictures of the board. Seems to be in good shape. No leaks or corrosion of any kind. Found a few chips with legs lifted which is on purpose I think. Once I find my multimeter I'll troubleshoot power although not sure what voltages to look for.

Kjtemp · « **Reply #4 on:** September 29, 2021, 08:01:58 PM »

Scratch that, found a few small caps that looked to have leaked.

shortrackskater · « **Reply #5 on:** September 30, 2021, 08:16:17 AM »

Shouldn't be too hard to replace those electrolytic caps. I'd clean that board as well and remove/re-seat the IC's. While you're at it, I'd check the voltage of that Alkaline battery.

Kjtemp · « **Reply #6 on:** September 30, 2021, 10:55:26 AM »

Yep I'll pull the board out fully to Id the caps. Could I replace the smaller ones with ceramic?

shortrackskater · « **Reply #7 on:** September 30, 2021, 03:08:59 PM »

I think most all electrolytic caps are polarized. Ceramic caps are not. Probably should use electrolytic but the value likely can be off a little if you can't find the exact value. The company Spin, Inc carries a number of them. I'll get another member to comment here as well.

Trisail · « **Reply #8 on:** September 30, 2021, 03:36:23 PM »

Aluminum Electrolytic Capacitors (AEC) are usually polarized. ( they do make non-polarized ones, but are not used often, they tend to be larger than the polarized ) The ceramic ones usually are not polarized. And rarely need to be replaced.

When replacing AEC you should try hard to get the same capacitance value, especially when used for timing or control purposes. The voltage rating can always be larger (not smaller) as long as the space and physical size are not a problem.

2 common mounting styles radial - leads are on the bottom and axial - leads are on opposite sides. You can interchange these, again as long as space permits. They are exactly the same, just mounting style is different. Be sure you insulate any lead that may short to something if you change the style. I usually leave the - (ground) lead as the long one. Less chance of problems if it gets grounded.

The reason the capacitors (resistors too) capacitance values are made in what is called common/standard values - the tolerance of the unit is usually 20%. The common values are spaced apart because of the tolerance. If you replace one that is different, you want to get ones as close as possible - you can measure the device and may find one close to the value you need. Google this and you can get a lot more information.

Replace with same capacitance value and voltage rating - higher voltage rating OK - lower not OK. Install with correct polarity and voltage otherwise they usually go out with a bang resembling a firecracker.

I have purchased many capacitors and can ship them reasonably priced. The older the unit being worked on - the more chance you may come across a value that is not one of the present standard values. You can sometimes purchase those values but the pricing is usually higher as volume/demand is low. Get as close as you can it should work, it won't blow up because of the capacitance value change, it just may not perform as well as the original design specification of the unit you are working on. Don't worry much about that, I have had to replace some and they worked just fine.

I did run across one capacitor that I did not replace on a CRT board recently - it was a very large size 10uf 50V AEC, todays offerings are much smaller as improvements have been made and the push to smaller devices is on going. I just couldn't bring myself to put a 5mm diameter 8 to 12 mm long cap in for one that was around 25mm diameter and 40mm long. I'm sure i could have and it should have worked, just couldn't convince myself to do it. The old one measured OK in and out of circuit

Kjtemp · « **Reply #9 on:** September 30, 2021, 06:27:59 PM »

All good info thank you. Sounds like regular caps will be the way to go. I'll update with the values I find.

Kjtemp · « **Reply #10 on:** October 05, 2021, 11:06:03 AM »

Found a few more caps that have leaked so right now looking for someone to replace all the caps. I'm hoping that will revive this board as everything else is in great shape inside/out of this machine.

Trisail · « **Reply #11 on:** October 05, 2021, 12:52:03 PM »

PM me I can help.

Kjtemp · « **Reply #12 on:** October 13, 2021, 08:51:03 PM »

I have found someone local to me to replace the caps and the alkaline battery. Hopefully this will bring it back to life. If it doesn't I think I'm out of options since it seems nobody has these.

Kjtemp · « **Reply #13 on:** November 16, 2021, 07:11:12 PM »

So I had all of the capacitors replaced and same thing. I am just getting a blue screen regardless if the board is plugged in or not so now I am focusing on power not getting to the board. Main reason why I think that is because I think the power to the lights in the buttons comes through the board? Not 100% sure. This thing is in such great shape I want to bring it back to life. What do you all think?

Badbaud · « **Reply #14 on:** November 17, 2021, 02:43:56 PM »

I did get a GON manual a while ago and PDF'd it.

If anyone wants a copy email me and I can respond with the manual attached.

Kjtemp · « **Reply #15 on:** November 19, 2021, 08:03:51 PM »

That would help me out a lot. Sent you a message

Badbaud · « **Reply #16 on:** November 19, 2021, 08:46:09 PM »

Didn't get it.

Kjtemp · « **Reply #17 on:** November 19, 2021, 09:40:42 PM »

Sorry about that. I tried again

Badbaud · « **Reply #18 on:** November 20, 2021, 12:20:17 PM »

Done, sent.

Kjtemp · « **Reply #19 on:** November 20, 2021, 05:39:51 PM »

Emailed you directly, did you get my message?

News:

NLG Site Navigation Menu

Author Topic: Games of Nevada GVP-7 help (Read 4310 times)