Screwed up...

tinsley

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I am switching all my Golden Tee stuff over to a dedicated GT cab. I made a huge mistake and thought the monitor was plugged into a iso transformer when i fired it, however, it wasn't. i know, stupid. was in a hurry and grabbed the wrong connector. ofcourse, this caused a blown fuse. replaced it and plugged up via iso xformer and it now continues to blow fuses. did i do major damage to the monitor? what should i look for that would be causing the blown fuses after not using a iso xformer? any help is appreciated, i have not done much with monitors so my knowledge level on them isn't to high...
 
At a bare minimum you probably toasted the bridge recifying diodes - pull one end and check them. If you get lucky, these are all that are bad. If not...keep checking components down the line from them.
 
how do you properly test r103? i tested d21/22 and both are shorted (i get the beep). how do i test r103?
 
am i looking at the wrong thing?> does r103 have 3 legs? maybe i'm confused here.
 
Well, it actually has 4 solder points, but that is because it is crimped into a bracket to stand vertically. it is right next to the filter cap. The bottom lead goes directly into the board, but the top leg is attached to the crimped bracket. If you look at the bottom, only two legs are connected to the traces, but all four must be desoldered to remove it...
 
i think i did this right. i set the black lead on the center pin, then the red to the other pins. had 2.7 on both readings.

it looked like this from under the board:


. (b)

. (r) . that was on the first reading. 2.7

. (b)

. . (r) that was on the 2nd reading. 2.7



looking for ic4 now....
 
Well, it actually has 4 solder points, but that is because it is crimped into a bracket to stand vertically. it is right next to the filter cap. The bottom lead goes directly into the board, but the top leg is attached to the crimped bracket. If you look at the bottom, only two legs are connected to the traces, but all four must be desoldered to remove it...

can i test it in place or does it need to be removed?
 
ok, on r103 i tested for ohms between the 2 points that connected to traces. read 2.7. am i just testing for shorts between pins on ic4? i just test every combination of all 5 pins for shorts?
 
Yes, just test for shorts. Stick your black lead on pin 1 or 5, then touch each of the others with the red. Sometimes you will get a tiny beep (if you have a beep test) that does not continue. That is fine. It is just a cap in circuit. If you get a steady beep, pull it and test again.

The easiest way to test all combinations is like this:

5 4 3 2 1
4 3 2 1
3 2 1
2 1

Moving the red lead to each number. Should only take about 20-30 seconds...
 
nice. thank you. i am testing 2 k7000s at the same time. one is the chassis i plugged in without iso xformer. we will call it chassis a. the other is a chassis that never worked and i capped. we will call it chassis b.

chassis a. blowing fuses on chassis. d21/22 shorted. r103 is at 2.7. ic4 untested still as i came up to post this first. so, i have 2 known issues, maybe 3. when it was plugged it, i saw a blue flash. maybe that was the diodes going? i don't know. can these diodes be picked up at radio shack?

chassis b. blowing fuses at fuse block for power supply, NOt on chassis. d21/22 tested open. r103 tested 2.7. ic4 tested with no shorts. again, doesn't blow chassis fuse, blows them on fuse block in cabinet. what else should i look for on this.
 
Chassis a - test IC4. Also test your HOT (Q11). It is a big black transistor mounted to the metal bracket over the flyback. Black lead on the center leg and red lead on each of the other two. A short indicates it is bad. Do not measure between the two outside legs, as they will read as shorted even if the HOT is good.

Also, when replacing either IC4 or Q11, you will need to make sure there is a mica insulator between the part and the wall it mounts to...
 
chassis b - unplug everything in the cab - monitor, coin door, marquee light, game pcb - and replace the fuse and power up. if the fuse still blows, then the problem is in the power supply or the power wiring has a short in it somewhere. If it doesn't blow, shut it off, hook up one thing, then power up again. If the fuse stays good, then that part of your cab is fine. If it blows, then that part is bad. Do this for each section to narrow down what is blowing your fuses.


Also, on the K7000 chassis - you MUST connect the DAG wire from the tube to the neckboard. If you don't, you will get arcing that will damage your chassis and blow fuses....
 
Chassis B is what is casing the fuses to blow. If it is unplugged, no blown fuse. when you plug it back in and power up it pops the fuse...
 
ic4 tested good on both chassis a & b. as did q11 on both.

chassis a: all i can find is d21/22 shorted. could that actually be the extent of plugging in without iso xformer or do you think i am missing something. can i pick up new diodes at radio shack to replace those 2?

chassis b: no clue. all the test i performed are good. not sure why it blows fuses at fuse block. weird...
 
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