U5000

[ttontis]

Long time lurker, first time poster. I am having problems with a Wells Gardner U5000 deflection board. Actually I let the factory smoke out of some of the switching power supply components. Here is what happened, one day the monitor just stopped working. I pulled the monitor to find out that the fuse blew on the deflection board. I went to the local electronics store and picked up a T3.15A fuse. Hooked everything up and snap crackle pop went the power supply. U101 blew cracking the component body exposing the bare die also almost burning R106 all the way through.
I pulled the board and found that R100 had some kind of green gunk growing around it, looks just like someone used water soluble flux and didn’t clean it off after making a repair. I do not think this is the case as the board material is discolored due to excessive heat especially where the leads enter the board. Discoloration can also be found at L103, D106, A, B and C.
I have ordered the replacement parts for D106 A, B and C, U101 and R100 and 106 I will also be replacing Q101. I am also looking to replace L103 but I am having a difficult time locating a 23uH3A toroid. I tried digikey and Newark.
Can anyone provide me with any information on any other areas of concern? This is the first time I have had to deal with this type of deflection board and since I have it torn apart I want to address any possible trouble spots. I would hate to get this back together only to have it fail a month or two latter.

Thank you,

Ted

[Kevin Mullins]

Wow....ya picked a helluva monitor chassis to pick for your first post. 

Those things are plagued with issues.
I'd have to dig up some notes from the first one I ever messed with.....what a nightmare.

[ttontis]

It has been a while from my last post and I am still working on trying to get the board up and running. Here is what I have done so far.
Replaced IC U500, Q501, C116, IC U101, Q101, D107, Q704, D708, R104, D104, Q703, Q708, Q705, C119, C118 and a Cap kit. I still have no power. I would like to take the board to work; I do not have an isolation transformer or o’scope at home. My question is do I have to have the fly back under load to get the recommended voltage readings? If so I can I connect a resistor to the fly back to simulate the load? I do not want to drag the whole thing into work.
I have not been hot to get this up and running but I just got another arcade and my wife is on me to get this one running so now I am under the gun

[Ken Layton]

Another one in the long line of Wells-Gardner pieces of crap monitors.

This model is plagued with problems. Wells-Gardner issued three different "service kits" to correct/modify/upgrade the circuitry to make it reliable. You need to call the Wells-Gardner parts department in McCook, Illinois and order these:

S04E0000-000F Service Kit, U2000/U5000 Power Supply Update

S05F0000-000F Service Kit, U2000/U5000 Vertical Sweep Update

S01J0000-000F Service Kit, U5000 Horizontal Output Transistor Update

[ttontis]

Ken,
  Thank you for the info. I saw you post in another thread and went to WG's web site to order it. They only list one kit and that's the vertical sweep. If I call them directly will they still have them available? Any chance you would have a parts list for the kits or do they come with adder boards that need to be blue wired in?

Thank you,

Ted

[Ken Layton]

There's a lot of parts not listed on Wells' website. You have to call them. The vertical kit includes a pre-made terminal strip assembly that's hardwired in.

[ttontis]

I got my power supply kit in the mail today. Here is what it came with Q101 MOSFET 6N60 which I found an NTE direct replacement NTE2379 was able to get it through digi-key and replaced it. D107 MUR490 funny thing the part numbers on the diode are MUR480E, again already replaced it. Here is the kicker R108 on the parts list is a .22 Ohm 2W resistor the kit came with a .47Ohm resistor. I replaced the old one with a .22 Ohm, I guess I spent 25 bucks on one resistor and an extra fuse. I downloaded Wells-Gardners troubleshooting guide for this board and I replaced everything in the no picture/Video (except for U500 I want to make sure that pig is dead before I drop 30 bucks on that little bugger), No Power Dead and Start up. Still can’t get it to fire. I guess I am going to bring it into work and see what I can find. If someone can tell me if I need to have the board on some type of load to get the right readings that would be helpfull. Also if anyone is looking for cross-reference info on this board just ask. I think I have a cross for just about every part.

Thank you,

Ted

[sarge]

You can isolate the power supply by lifting jumper W159 and connecting a 60 watt light bulb in series to ground.  If your light bulb lights,  measure your b+ which should be around 120V.  This will at least specify whether the problem is in your supply or your load.

[ttontis]

I am getting closer. I replaced R108 with the one in the kit. I am now getting a high pitch hum D107, R104, 105 and L103 get hot. Seems I am not drawing enough current to blow the fuse so what gives? (we are talking on for 30sec or lesss) I assume that I will have to replace Q101 again. I am going to try and get some voltages and post back with the values I find. I just do not want to nuke the components again.

[ttontis]

OK stick a fork in me I am done  I am going to take this board to the local trap rang and shoot it. I isolated the power supply as sarge suggested well I know it is the power supply. Smoked R106 replaced it and smoked it again. With out having to replace every thing in the power supply circuit any other ideas? Anyone know of a drop in replacement board for the U5000? any one have a good U5000 they would be willing to part with?

[SirPeale]

If you're repeatedly smoking that resistor, check the components that come before and after it in that line.  Something's out of whack.

[ttontis]

That's just it everything seems to check out fine. I willing to bet T101 is bad, I might remove it and work my way back. Is there a full schematic for this assembly floating around? The service manual only has bits and pieces.

Ted

[SirPeale]

I've got one, but it's too big to be uploaded here. 

edit: duh, I should have realized.

http://www.wellsgardner.com/pdf/Schematics/U5000_25_inch.pdf

[ttontis]

Peale,

Thank you. ripped out the transformer, Q101 and U101 (Q101 was blown). Working my way back. I think I am on my way to getting this thing licked. The schematics will be a real help.

Ted

[ttontis]

Here is the update.
Q101, R108 and 106 smoked and replaced. I replaced U101 just to make sure it wasn't bad. Went through the schematics and found two locations that the pads separated from the copper track. They were in locations that showed signs of parts getting real hot, not in any of the locations I smoked parts. I replaced the parts and added jumper wires to the open locations using cut resistor leads. They were straight shots and didn't need any insulation, they didn't cross over any tracks.
Currently the problem is Q101 the Gate is 0v, Drain is 165v and the Source is .7v manual says G=8v D=153v S=.1v. I am guessing that the Emitter is the Source, the Base is the Gate and the Collector is the Drain. The service manual has them as E,B,C? Everything checks out up to Q101 except for D107 it is at 165v however, this is part of the MOSFET circuit and I think that once I replace R108 I will get the 300v I need.

I will send the next update once I get the resistor.

Thank you,

Ted

[ttontis]

Here is the update my hunch about T101 being bad was right on the money. From the theory of operations section I assumed that because U101 wasn't shutting down when it would reach an over voltage state the transformer was bad. I just had no way of testing the transformer under a load. This was the ultimate demise of the power supply that caused all my problems from the start.
By the way I sent it out because I was so frustrated with it. I should have played my hunch and ordered a transformer. Well any way you look at it I had a professional look over the whole thing and make sure nothing else had to be replaced.
I just wanted to thank everyone for the help.

Ted