Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: candyman on March 09, 2007, 05:15:34 pm
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Hi All,
Yes, it's another nightmare U5000 problem. I got the monitor a year ago an recently started to see if I could get it going. So far I have put a cap kit in, replaced R123, D106 diodes, U701, and Q704. when powered up, all I get is a light ticking sound (overload protection circuit??) . Please help with my next move :banghead:
Aaron
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Blown horizontal output transistor, or maybe the B+ is turned up too high.
More likely the first. The second usually happens on temperamental K7500s.
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Peale,
I checked out the HOT, and it checks ok. I than went to check B+, only 38vdc. I went and checked all TPs.
TP103- 105 all 60vac
TP106 175vac
TP201 0vdc
TP202 38vdc
TP203 12vdc
TP204 3vdc
TP205 14vdc
I am guessing there is a problem somewhere in the PS section. Any ideas?!?
Thanks for any ideas
Aaron
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I am guessing there is a problem somewhere in the PS section. Any ideas?!?
Thanks for any ideas
Aaron
The switch mode power supply will go into shutdown/protect mode if the current draw is too high. To isolate an SMPS supply issue from the rest of the chassis locate the B+ jumper from the SMPS. Unsolder the jumper to isolate the supply from the rest of the chassis and connect an ordinary 120v light bulb to the supply output (I usually use a 20w lamp) and power up the chassis, if the bulb lights and B+ is stable then something else in the chassis is shorted causing the SMPS to go into shutdown. If B+ is still low or at 0v then the supply is dead.
Disclaimer - when you hook up the light bulb and/or work with the SMPS you are dealing with potentially dangerous voltage levels, use extreme caution!!
D
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Thanks for the info I will check it out in the next day or two and let everyone know. In case I have a problem locating the jumper area could you point me in the general area?
Also I do understand the voltage danger involved.
Thanks for your help
Aaron
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In case I have a problem locating the jumper area could you point me in the general area?
I don't have a U5000 right handy or a schem in front of me to give you the jumper number, but if you look at the chassis, you will notice the SMPS is in it's own "section", with a black line border around it (looking at the top of the board). The jumper is the only jumper to "cross the border", so to speak.
D
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D,
I removed the the jumper and installed jumper to a 20w bulb. It lit just fine , and B+ stable. Any thoughts on were to go next?!?!
Thanks for your time and info.
Aaron
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If you hadn't already installed the cap kit, I would tell you to replace all the caps in the PS section, although it's possible something else caused it to go bad.
There are some small transistors in the high voltage section that Well Gardner Support lists as possible suspects. If their site doesn't have a troubleshooting guide for the U5000, call the 1-800 number and ask their tech support for some suspects. (John is very helpful.)
When a D9200 I was working on had the same problem, they had me check and change those transistors, but the final solution ended up being bad caps in the PS section.
If it becomes too much of a headache, you could always spring for the K7500 chassis replacement they have on their site for the U5000.
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Hi,
I did install cap kit (1st thing all my monitors get), and checked power supply-OK(see previous post). I guess my problem is some place after PS. I'm still checking componets and asking for ideas. I know I could/should replace with K7500, but I've put more time/effort into this one than most others and I will not give up (although I should) even if I have to replace every part! :badmood: :banghead: :cry:
Have a SWEET DAY!
Aaron
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There are several "service kits" Wells-Gardner issued to correct the design defects of the U-2000 and U-5000 chassis. That's why Wells-Gardner discontinued those models and replaced them with the k7400 and k7500 respectively.
There's a kit to correct the power supply problems, a kit to correct for frequent blowing of the horizontal output transistor, and a kit to correct for a shorted vertical output IC (the most frequent problem on this chassis). Nine times out of ten you'll have a shorted or leaky vertical output IC loading down the power supply causing the supply voltage to drop/shutdown. The "Vertical Sweep Kit" corrects the problem so you don't blow another one and it includes a new vertical output IC in the parts.
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Are these kits still available thru WG or do we have to find them elsewhere?
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The "service kits" are ONLY available from the parts department at Wells-Gardner.
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Ken, thanks for the info, I sent an email to W.G. asking for info on these kits.
Thanks
Aaron