Replaced flyback, caps, fuse. CRT still blank.

scottkeen

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I ordered parts from The Real Bob Roberts (great place to order parts!)

I have a Wells Gardner K7000 series (horizontal, landscape). It's in the Dynamo Z-Back arcade cabinet for the X-Men vs. Streetfighter arcade game. Currently, the game fires up, you can hear the sounds, but the CRT appears to be dead.

First, I replaced just the flyback transformer. Plugged everything in. Nothing, not even a buzz or hum from the CRT. Dead as a doornail.

Next, I replaced the fuse. Plugged everything and *flash*, the fuse blew. OK, so I got a short somewhere...

Next, I replaced every capacitor that came in the cap kit. Put in a new fuse. Plugged everything. Surprisingly, I got a crackle then buzz or hum from the CRT. But on the screen, nothing. I read somewhere that I should see an orange glow in the neck tube. Also nothing.

I don't know what else to do. Any suggestions?
 
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I'm unfamiliar with increasing the voltage or B+. I don't know about electronics, just can use a soldering iron.

The only thing I've tried was cranking the two black knobs on the flyback (focus and blackness?) in both directions and there was no change on the screen.

If you could give me step-by-step things to try, I'd really appreciate it.
 
There's a big white resistor that hangs off the side of the chassis. Check you B+ at the leg of this resistor.....the leg closest to the tube. This is DC volts...let us know what you get.

Edward
 
sounds like your going into HV shut down.

you cannot change the B+ on a K7000 it has a fixed regulator.

your B+ should be 130vdc measure it with your meter.

put your black lead on the frame any where and your red lead on the resister tab closest to you. its the big one hanging on the outside of the frame. behind the fly on the left of the chassis.

the tab closest to you should read 130vdc +/- 1 volt. blue wire i think.
the opposite side should read 166vdc +/- a volt or two. red wire i think.

if you dont get those voltages then something else is wrong.

we will go from there when you report back with your findings.

Peace
Buffett
 
ELutz,

Sorry for my lack of knowledge of electronics, but how do I test it?

I see the big white resistor. I have a cheap analog multi-meter. What do I set my multi-meter to and what do I touch the red and black leads from the meter to? I assume I have to do this with the power plugged in.

Edit:
buffett, thanks for the instructions for newbies.

I'll report back what I find.
 
These are the two readings I've gotten from the big white resistor. It's hard to tell the exact number on the meter because I can only set the scale on my meter to 150 or 1000. I set it to 1000.

The lead closest to me (back of the monitor):

IMAG0435.jpg


The lead farthest from me (front of the monitor):
IMAG0436.jpg
 
set your meter on the 150 setting.

i cant tell if you are good or not on the 1000v setting.

your meter should peg out on the 160v side and almost peg pot on 130 side.

if it pegs out on both tabs then you are probably in HV shutdown.


you really need a digital meter for this kind of electronic work. it will be a hundred times more accurate and eayser to use.
plus you will need to test other things like diodes and transistors. having a digital meter would be the way to go.

Peace
Buffett
 
Looks like the B+ is in the 160 range. Most likely a bad trace or broken pad...
 
I think the B+ was fine... until I just fried it (grounded the far lead to the chassis) when I was taking a meter reading of the farthest lead. There was a flash and spark. Fuse didn't blow, but I think I fried the B+. Here are the readings with the meter set to 150.

Closest lead (before I fried it)

IMAG0437.jpg


Farthest lead (after I fried it)

IMAG0438.jpg


Closest lead (after I fried it)

IMAG0439.jpg
 
yea looks like you smoked the VR when you grounded it to the heat sink.

i have done that before so don't think that your the only one.

otherwise it looked like it was fine.

your gonna need a digital meeter that has continuity to test any further with accurate results.

a broke trace or pad is something that physically broke in two or more pieces.
kinda like a piece of concrete side walk that has split and has cracks all over in different directions.

you will probably will need to replace the VR and possibly the H.O.T.

if it wont come on now it is in HV shutdown.

so get a better meeter and we can go from there.
or just replace the VR and test again.

Peace
Buffett
 
I will try and find the VR (is this the same as B+)? It says on it "ROYAL 25W 180Ω J". Know where to get one? Does Bob Roberts sell these? Is it a standard item at the local Radio Shack?

When I plug it in, there's not much difference than before I blew the VR. The monitor still buzzes and hums, still no picture.

I took note of the board model numbers while I was taking it out.
Main board - P538
Neck board - P448B

Should I just buy a new set on eBay? They are "untested" and go for about $25 with shipping. I figure maybe that would be worth it for the parts and maybe I can take parts from each and make 1 working board.

Also, what's a decent digital meter to get? I have a $100 gift card for Lowes or Home Depot. Hate to spend it on something I may not use much. I can't pour too much money into this arcade.
 
The VR is IC4 - mounted on the left wall behind the flyback. It'll be either an STR3130 (4 legs) or an STR30130 (5 legs). Replace it with the same # of legs.

STR3130 = NTE 1742

STR30130 = NTE 1777
 
The VR is IC4 - mounted on the left wall behind the flyback. It'll be either an STR3130 (4 legs) or an STR30130 (5 legs). Replace it with the same # of legs.

STR3130 = NTE 1742

STR30130 = NTE 1777

It's the STR30130.

So the white brick looking thing isn't blown?
I just need to replace the STR30130?

Thanks,
 
Don't know if you have Harbor Freight on the islands, but they have a cheap digital multimeter for about $5.

As for Home Depot, they have this one for $20 and it would work just fine for what you need to do...

http://www.homedepot.com/h_d1/N-25e...53&langId=-1&keyword=multimeter&storeId=10051

No HF over here. Just have a small pathetic Radio Shack (mostly consumer electronics), and Lowes and Home Depot.

Would any of these stores carry the STR30130, or am I going to have to order it and wait for it to arrive before we can continue?


Thanks again everyone for your continued help and patience with me!
 
No HF over here. Just have a small pathetic Radio Shack (mostly consumer electronics), and Lowes and Home Depot.

Would any of these stores carry the STR30130, or am I going to have to order it and wait for it to arrive before we can continue?


Thanks again everyone for your continued help and patience with me!

You could check these places to see if any carry the NTE 1777. If so, you're good to go. make sure you get an insulator if yours is missing or torn...

http://www.nteinc.com/NET_St_lst/HI.shtml
 
You could check these places to see if any carry the NTE 1777. If so, you're good to go. make sure you get an insulator if yours is missing or torn...

http://www.nteinc.com/NET_St_lst/HI.shtml

Thanks. All those are on Oahu (different island). I will have to order one and wait for it to arrive then get back to this thread.

Anything else I should order while I'm at it?
 
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