John's Arcade Forum - Classic Arcade and Pinball Collecting and Restoring Discussion Forum - RETRO MAME - Nintendo Vs Forum

I am attempting to Change out the power supply on my English mark darts machine, (never changed power supply before).  I have 120 reading fine, but my +5 and +12 are really high.  Now I tried to use the adjustment voltage pot on the new power supply but I think I am a boner and broke the pot....is it suppose to keep spinning around...no matter what my +5 the closest I came on my voltmeter was 8.5..  So did I break it? Anything I can do besides starting over?

Sounds like you broke the pot on the power supply.

Are you sure you can put that in the dart board? Doesn't that require weird voltages?

Dang, I thought so.
As far as if it's doable I believe so...I actually got the idea from one of your original threads on klov. I have the same dart board as you.

http://forums.arcade-museum.com/showthread.php?t=108948&page=4

Ken Layton talks about it half way down

Ah, ok! Cool. I didn't realize the 21V would work with only 12V.

So, get another supply? :)

When you adjust voltages on a power supply like that you are really just adjusting the +5V. Make sure that voltage is cool. The others will go for a ride when you adjust but the +5v is the only one you want to test while adjusting the knob.

Thanks..yea I ordered a new one. rookie mistake.
One more question..I have 16 gage wire...is that okay to use coming off the power supply terminals..too big?

Too big is not a problem. You can use 18 or 20 too for the DC voltages.

I been working on trying to get this new power supply hooked up. before i connect everything to the board, i checked the Voltages. I have 120 coming in just fine, but on my +5, the lowest i can get for a reading is 8.5...i can't turn the pot down anymore. Any suggestions on why this may be happening?
Thanks

You sure you are reading it right? That doesn't seem possible, espcially after getting a new one. Show us how it's hooked up.

okay, tonight..i will take some pics. Thanks.

I don't think you have it wired up right. Did you check the value of the power supply before you wired it in. Are you sure you are measuring from Ground reference and not -5V.

Okay, so I was checking the +5 on the AC current on my multimeter...dumb I know, I changed it to DC and now I get correct readings on all. Thanks guys I'm sure I will have other questions. Going to hook it up soon.

Still not starting a game..is it possible to check the voltages on every chip on the board? Wondering if I have a bad game rom chip. If so, does anyone know how I guy would get a new one...I really want to drink beer and play tic tak toe on this thing. Thanks

i usually only bother to check the voltage at one chip, that's usually enough verification to know if the power supply is working. Any voltage above 4.5V is fine, above 4V is probably fine. and nothing more than 5.5V.

Without a rom burner it is very difficult to find out if you have a bad rom unless one of the legs broke off. Take the time to pull each chip, inspect, and put it back. Sometimes just reseating chips is enough to get a game working.  If you need eproms there are plenty of people online that can do them. I can, as well as http://hobbyroms.com

Do remember though, it very likely could not be the eprom and replacing them is going to do nothing.

Thank you..I will try and re seating everything.

Hey guys just to put this thread to bed. I reseated every chip on the board and it came to life with the new switcher power supply.  Played 2 games so far no problems. Thanks for everyone's help. beer time.

Ive seen a rash of bad cheapo switchers floating around that do that..

That's why I always order HAPP PRO models.