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Author Topic: Troubleshooting a WG 25k7191 no picture blowing fuse  (Read 1083 times)

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joej85a

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Troubleshooting a WG 25k7191 no picture blowing fuse
« on: March 19, 2020, 04:08:43 pm »
Hey guys, Im Joe, from NC, new to the board, but been reading for a while.  I am having an issue with a Golden Tee 2k cabinet I recently picked up.  It has a Wells Gardner 25k7191 monitor in it that has not worked since I purchased it.  I have read about the common problems, and visually inspected the board.  Blown fuse, cracked Flyback.  So I went ahead, ordered a new flyback, fuses, cap kit, IC4, and HOT.  I understand the HOTs commonly fail so I wanted to do it as maintenance regardless.  I also downloaded the manual for the k7000 series (which is awesome), and have been working with the troubleshooting diagram in it.  Here is what I have done:
1. full recap except for cap C55 which I did not realize was not in the cap kit.  It visually looks ok, no leaks, not bloated. I have recapped consoles for some time so feel like it is not an install issues (but maybe?!)
2. replaced the HOT
3. replaced IC4
4. replaced the flyback
5. installed new Slowblow 2amp fuse.

Installed back into the cabinet and get immediate fuse blow.  No delay, immediate.  So referred back to the troubleshooting guide and it says with no hi voltage, and with blow fuse, check for a short on legs 1-4 of IC4 and for a short at the HOT.  Leg 1 of my new IC4 shorts to ground.  Leg 1 and 3 of the HOT short to ground.  I removed the HOT and the leg 1 short to ground on IC4 remains.  I removed IC4 as well, and the leg 1 pad still shorts to ground, as does the corresponding pads of the HOT (pad for leg 1 and 3).  I am starting to hit a wall as it now just says to look for a cause of the short in the circuit.  I have checked the diode bank D19-D22 and they seem to check okay, D23 and D24 however appear to be allowing voltage both directions, but I can't tell if it is feeding back.  I did not take them off the board to test.

At this point, I am looking at the retuning cap, c36 cut it is not shorted out.  So any help or ideas would be AWESOME!

Thanks guys! and thanks for reading my first post.

grantspain

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #1 on: March 19, 2020, 05:09:54 pm »
so if you isolate the b+ to the flyback and add a 40w lamp to the b+ line as a dummy load does your fuse still blow?

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #2 on: March 19, 2020, 08:58:33 pm »
I will have to read up more on the lightbulb test to make sure I do it properly.  I have heard people refer to it, but not 100% sure on the details. Iíll get on it and get back with the results.  Thanks so much!

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #3 on: March 20, 2020, 04:22:56 am »
any one of the poly caps and the diode around the deflection header will cause the fuse to blow immediately
using this method will prove your b+ supply is correct and there is no issue in the regulation circuit
its the first thing i do on 7000 series chassis when they come in for repair
make sure you use a anti surge fuse also

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #4 on: March 20, 2020, 10:14:16 am »
1) Suck solder off pin 2 of the flyback and make sure the pin is no longer touching the pad around it.
2) Measure resistance across pin 1 and 3 of the flyback. Zero ohm/short? If so go to 3.
3) Suck solder off middle pin (COL) of the HOT and here too make sure the pin is no longer touching the pad around it.
4) Measure resistance across pin 1 and 3 of the flyback. Zero ohm/short? If so go to 5.
5) Desolder C36.
6) Measure resistance across pin 1 and 3 of the flyback. Zero ohm/short? If so go to 7.
7) Desolder D18 and C69 and test them out of circuit.
« Last Edit: March 20, 2020, 10:18:48 am by princess prin prin »

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #5 on: March 20, 2020, 11:36:40 am »
any one of the poly caps and the diode around the deflection header will cause the fuse to blow immediately
using this method will prove your b+ supply is correct and there is no issue in the regulation circuit
its the first thing i do on 7000 series chassis when they come in for repair
make sure you use a anti surge fuse also

Thanks so much for this.  Where is the easiest place to isolate the b+? Just pull a leg on the VR?

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #6 on: March 20, 2020, 11:37:53 am »
1) Suck solder off pin 2 of the flyback and make sure the pin is no longer touching the pad around it.
2) Measure resistance across pin 1 and 3 of the flyback. Zero ohm/short? If so go to 3.
3) Suck solder off middle pin (COL) of the HOT and here too make sure the pin is no longer touching the pad around it.
4) Measure resistance across pin 1 and 3 of the flyback. Zero ohm/short? If so go to 5.
5) Desolder C36.
6) Measure resistance across pin 1 and 3 of the flyback. Zero ohm/short? If so go to 7.
7) Desolder D18 and C69 and test them out of circuit.

Prin, thanks for this awesome walk through.  Currently my VR (IC4) and the HOT are out of circuit.  Do I need to reinstall them for the above test?

Thanks all!!!

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #7 on: March 20, 2020, 02:34:08 pm »
The B+ is isolated by sucking solder off pin 2 of the flyback (well it still goes to the neckboard but not relevant). For a bulb test you can connect the bulb to the small pad near pin 2 of the flyback and to a ground point (big heat sink for instance). To do the things I said it doesn't matter if IC4 is in or out. For the bulb test it needs to be in. The HOT can stay out for these tests.
« Last Edit: March 20, 2020, 02:37:33 pm by princess prin prin »

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #8 on: March 20, 2020, 05:34:53 pm »
great, thank you for the clarification.  I will try the bulb trick and see what I get. 

With both the IC4 and the HOT out of the board, I do NOT get a short between pins 1 and 3 of the flyback.  I did verify that leg 2 is indeed isolated.

So... No short there, anything else to check before moving to the bulb test?

Thanks again everyone for the expertise.

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #9 on: March 21, 2020, 04:48:28 pm »
Gentlemen!

I feel like some progress was made today.  At your suggestion I did the bulb test, here are the details.

1. Isolated pin 2 of the Flyback, verified it was isolated.
2. Re-installed the VR (IC4)
3. Put in a new fuse
4. Did NOT reinstall the HOT
5. Attached the positive of the bulb lead to the small pad beside the leg 2 pad of the isolated Flyback
6. Attached the negative of the bulb lead to the ground plain

Installed in the machine, hooked everything up except the degausing lead, and powered it up.  The bulb came ON nice and bright, and it did NOT blow the fuse.  So with that result, I can verify the VR is working and I am getting High Voltage to the flyback correct? Suggestions on where to go now?  Re-install the HOT and do the bulb test again? Thanks all for the help so far, I am excited.


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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #10 on: March 21, 2020, 05:08:11 pm »
When you do a bulb test you should also check the voltage. I suggest to check it on R101: on one leg it should be 130V and on the other 12V. Also, before putting the HOT back in circuit test it with the multimeter in diode setting. A good HOT will give readings as in the picture below (they don't have to be exactly the same but in that range). Reversing the leads (e.g. red on collector, black on base) will give OL (or whatever it displays when the leads don't touch anything). Across base and emitter you only read 40-50 ohm.


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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #11 on: March 21, 2020, 05:23:07 pm »
When you do a bulb test you should also check the voltage. I suggest to check it on R101: on one leg it should be 130V and on the other 12V. Also, before putting the HOT back in circuit test it with the multimeter in diode setting. A good HOT will give readings as in the picture below (they don't have to be exactly the same but in that range). Reversing the leads (e.g. red on collector, black on base) will give OL (or whatever it displays when the leads don't touch anything). Across base and emitter you only read 40-50 ohm.

Thanks Pin, I will check the voltage and report back.  Also, I am checking my HOT as suggested and using 2 different meters I get "566" from B to C, and "594" from C to E, OL when reversing the leads, and 53 ohms across B to E.  There is no decimal before the numbers but I am wondering if the meters just dont have decimal or it is measuring in millivolts?

I tested the replacement HOT I ordered and get "564 from B to C, then "586" from C to E, OL reversed, and 43 ohms across B to E.

Lastly, I noticed on my schematic of the 7191, the factory VR is a STR30123.  When I got the board, it had a STR30130 in it, so that is what I replaced it with.  Curious if that could be causing issues. 

Again I will test the voltage and report back! Thanks!!


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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #12 on: March 21, 2020, 09:12:04 pm »
Okay, back with the results, I am definitely having some kind of High Voltage issue.

I hooked everything up, powered it up, light bulb came back on, and I tested voltage on both sides of R101.  I have 12.4v on one side and 154.8v on the other.  From the schematics it looks like it should not be more than 130v.  I am assuming this is one of the issues I am having.  Could this be due to the 30130 instead of the 30123?  This is a new VR.

Also, as I was testing, something started smoking, it looked like it was coming from either R99 or R96, but the bulb did not go out.  I immediately unplugged the power.

Visual check of R99 there may be some staining or oil on the side, hard to tell what its from.  R96 looks fine visually.

Thoughts?

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #13 on: March 21, 2020, 09:24:57 pm »
if you have a str30130 its a 25" chassis
in any case b+ should be 130vdc with that ic, if you loaded the b+ line correctly then your regulator ic is bad

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #14 on: March 21, 2020, 10:36:02 pm »
if you have a str30130 its a 25" chassis
in any case b+ should be 130vdc with that ic, if you loaded the b+ line correctly then your regulator ic is bad

Thanks for the info.  Aggravating as it is a brand new one, but my guess is that there is something else going on, that must have killed the new one.  I suppose the best next step is to order a new one, install and then do the bulb test again.

Along those lines, to do the Bulb Test, is it okay to just hook power up (from the isolation transformer) to the chassis board to do the test, or does it need to be hooked to the yoke and grounded to the screen ground, etc, etc?

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #15 on: March 22, 2020, 06:10:30 am »
To confirm that the culprit is indeed the regulator IC you could do a bulb test this way.

- Lift one end of jumper J27 from the PCB as shown in the pic (be careful not to damage the pad).

- Connect the bulb to the lifted jumper and ground (IC4 pin 1, jumper JB, big heat sink, etc.).

- Desolder C57 and connect (remotely with wires) the positive side to the lifted jumper (or other points on solder side connected to it) and the negative to a ground point (IC4 pin 1, jumper JB, etc.). In other words C57 needs to be in parallel with the bulb.

- Keep pin 2 of the flyback desoldered from its pad (or alternatively lift one end of the jumper to the left of J27).

- Voltage at the lifted jumper (or the side of R301 with the blue wire) must be 130V or the regulator circuit (most likely the IC itself) has a fault.

All this assuming your old and new ICs are STR30130 and not STR3130.
« Last Edit: March 22, 2020, 06:28:45 am by princess prin prin »

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #16 on: March 22, 2020, 10:22:02 am »
To confirm that the culprit is indeed the regulator IC you could do a bulb test this way.

- Lift one end of jumper J27 from the PCB as shown in the pic (be careful not to damage the pad).

- Connect the bulb to the lifted jumper and ground (IC4 pin 1, jumper JB, big heat sink, etc.).

- Desolder C57 and connect (remotely with wires) the positive side to the lifted jumper (or other points on solder side connected to it) and the negative to a ground point (IC4 pin 1, jumper JB, etc.). In other words C57 needs to be in parallel with the bulb.

- Keep pin 2 of the flyback desoldered from its pad (or alternatively lift one end of the jumper to the left of J27).

- Voltage at the lifted jumper (or the side of R301 with the blue wire) must be 130V or the regulator circuit (most likely the IC itself) has a fault.

All this assuming your old and new ICs are STR30130 and not STR3130.


Thanks so much Pin, I will give this a try.  Can you verify if for the bulb test I can just hook up to the power from the isolation transformer and forego the other connections for the chassis? Getting everything installed in the cabinet to do the bulb test is proving precarious.  Thanks!

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #17 on: March 22, 2020, 11:48:09 am »
It's best to connect everything except for the video input when you power the chassis.

As for your faulty regulator there are a lot of conterfeit IC's out there so check your source.


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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #18 on: March 22, 2020, 11:55:09 am »
It's best to connect everything except for the video input when you power the chassis.

As for your faulty regulator there are a lot of conterfeit IC's out there so check your source.

Ok, and I got the Vr IC from arcadepartsandrepair which seems to have a good rep.  Maybe just a bad one.

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #19 on: March 22, 2020, 11:59:02 am »
Peter is a good guy.  He will replace the IC if it was truly bad.

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #20 on: March 22, 2020, 01:20:28 pm »
It's best to connect everything except for the video input when you power the chassis.

As for your faulty regulator there are a lot of conterfeit IC's out there so check your source.

Ok, and I got the Vr IC from arcadepartsandrepair which seems to have a good rep.  Maybe just a bad one.

That is what I had read.  My guess is something on the board cooked it.  I have ordered a new one, and will try the bulb test before I try it in the full circuit.  My fear is that something on the board is killing the regulator and I wonít know until I try it again. I omhed it out via the FAQ sticky and it was all over the place, so itís shot for sure.

Also, Pin, thanks for the further test info. I will try that just to verify.

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #21 on: March 22, 2020, 01:51:22 pm »
Can you verify if for the bulb test I can just hook up to the power from the isolation transformer and forego the other connections for the chassis?

If you follow my instructions the voltage regulator circuit will be completely separated from the rest of the chassis so power is all it needs.
« Last Edit: March 22, 2020, 02:05:10 pm by princess prin prin »

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #22 on: March 22, 2020, 10:40:33 pm »
Can you verify if for the bulb test I can just hook up to the power from the isolation transformer and forego the other connections for the chassis?

If you follow my instructions the voltage regulator circuit will be completely separated from the rest of the chassis so power is all it needs.

Okay so quick update. I took Pin's advice and isolated the regulator IC per the instructions posted.  Pulled the jumper, wired C57 in parallel and hooked up the bulb, and got a reading of 160.2vdc at the jumper leg.  So the new regulator IC4 is toast.  Just for fun, I soldered the original regulator IC back into the board and did the same test, got a reading of 162.4vdc, so the old one is toast too.  Not real surprised there, but is it odd they both failed and apparently in the same way that pushed them up to 160vdc? My input voltage from the isolation transformer is 128v.

So as I said before, new regulator is on the way.  But does this give me any direction? Assuming the new one goes in and I test it as above, and I get a good 130vdc, what is the best next step to avoid toasting regulators over and over? 

Again, thanks all for the sage advice, I do appreciate it and other than the annoying chasing ghosts, it has been a fun process so far.  Looking forward to seeing it fire up.

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #23 on: March 23, 2020, 08:49:11 am »
The circuit of your last test is like this. There isn't much that can be at fault. Check the three electrolytics (C55, C56, C57), the resistors and then there is only the IC left.

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #24 on: March 23, 2020, 12:33:10 pm »
The circuit of your last test is like this. There isn't much that can be at fault. Check the three electrolytics (C55, C56, C57), the resistors and then there is only the IC left.

Thanks Prin, I will check the above. All the caps are new, so I am hoping no issue there.  I did order new resistors when I ordered the regulator, so now it is just a "wait until they arrive" scenario.


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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #25 on: March 24, 2020, 06:30:53 pm »
Update: New parts should be here tomorrow.  I have been doing a lot of reading and testing and I think I may have found my culprit.  C38 is shorted, dead. Both pads short to ground when in circuit, when removed, it tests as shorted. Iím excited to find a shirt to ground! I have ordered one so we shall see!

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #26 on: March 24, 2020, 07:44:25 pm »
Also, I cant seem to get the search function to work in the forums.  Cannot connect to search daemon or something to that effect.  Is that just me?

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #27 on: March 24, 2020, 08:08:00 pm »
Also, I cant seem to get the search function to work in the forums.  Cannot connect to search daemon or something to that effect.  Is that just me?
Saint is working on it.

http://forum.arcadecontrols.com/index.php/topic,162229.0.html


Scott

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #28 on: March 24, 2020, 09:44:02 pm »
Also, I cant seem to get the search function to work in the forums.  Cannot connect to search daemon or something to that effect.  Is that just me?
Saint is working on it.

http://forum.arcadecontrols.com/index.php/topic,162229.0.html

Thanks for the info Scott

Scott

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #29 on: March 25, 2020, 12:40:50 am »
C38 is shorted, dead. Both pads short to ground when in circuit, when removed, it tests as shorted.

Is one of the pads on the chassis it was soldered to shorted to ground?

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #30 on: March 25, 2020, 03:36:00 pm »
C38 is shorted, dead. Both pads short to ground when in circuit, when removed, it tests as shorted.

Is one of the pads on the chassis it was soldered to shorted to ground?

I installed the new C38 along with the others I ordered and the short is gone.  Correction, neither pads for c38 go to ground now.  I also found that I had a dead short in c37 as well, which of course I did not order, so I just put an order in for it and c44 just to go ahead and get them all changed.  Wish I had seen that full kit with these in it.  Anyway, new regulator (ic4) is here.  I am going to install and see what I get with Prin's truncated test that isolates the regulator.  I also replaced all the recitifier diodes and b+ filter cap.  I'm half away to a new board! haha.

Ill keep you all posted.

joej85a

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #31 on: March 26, 2020, 12:52:55 pm »
So, in the midst of my troubleshooting, I searched ebay and found a listing for another k7000 chassis that was verified to be working.  However, the seller stated that although it works, the image is too big for the tube.  The picture shown shows just that, an image that is going off the sides of the tube.  He had it hooked up to a 19" monitor, but as I look at the pictures, it is a P538 board, just like mine for my 25" monitor.  Im thinking maybe he just has it hooked up to the wrong tube, and I picked it up for $45.

It came in today and it is indeed a P538 board, model number k7197.  It also has the pincushion board attached.  Again, searching the 7197 brings up results that say it should be for a 25" from what I can find.  It also has the STR30130 regulator.

The main different I see is a different neck board.  My neckboard is a P448A (on my original board) and this new board has a P456 board, that is definitely not compatible with my yoke.  It is an 8 pin and mine takes the 10.  It also appears to have been desoldered and resoldered looking at the connector closest to the HOT.

So question is, are neck boards changeable? Could I disconnect my P448A and attach it to the 7197 board? As I am bringing back this other board to life, I would love to play some GT2k.  If it matters my tube is a Philips M08X :dunno
 
« Last Edit: March 26, 2020, 01:03:09 pm by joej85a »

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #32 on: March 26, 2020, 01:56:38 pm »
P538 is the main chassis board for 25" (and more rarely 27") monitors and P456 is the neckboard for 19" monitors (it wouldn't fit any 25" tube) so this combination doesn't make sense and cannot be original. This P538 would need to be carefully inspected to see if it's still for 25" or if it has been modified. The pincushion board (if that's what it actually is) is necessary for 27" monitors.

Does it have these caps? same values?

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #33 on: March 26, 2020, 02:10:26 pm »
P538 is the main chassis board for 25" (and more rarely 27") monitors and P456 is the neckboard for 19" monitors (it wouldn't fit any 25" tube) so this combination doesn't make sense and cannot be original. This P538 would need to be carefully inspected to see if it's still for 25" or if it has been modified. The pincushion board (if that's what it actually is) is necessary for 27" monitors.

Does it have these caps? same values?

It has a .0036 in C36 and C69 has been replaced at some point with a new smaller brown style that says "602G". So wouldnt that be .00602? Close enough?

If the pincushion is needed for 27 will it work on 25 or would it been to be removed and the cap and resistor at r69 and c28 need to be re-installed?

I also see that the HOT is a "2302 SK9422".  Not sure if that is relevant, but someone took the time to write a note, in sharpie above it, it is a "2302" per the identification on it.  I do know that the 7191 uses a D1398.
« Last Edit: March 26, 2020, 02:22:21 pm by joej85a »

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #34 on: March 26, 2020, 03:22:25 pm »
C36 and C69 are correct for 25". The HOT has been replaced with a different type (still with damper diode, hopefully compatible enough) and the vertical board can stay (I don't know if it's indeed for pincushion without seeing it). The neckboard can be swapped.

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #35 on: March 26, 2020, 04:51:46 pm »
C36 and C69 are correct for 25". The HOT has been replaced with a different type (still with damper diode, hopefully compatible enough) and the vertical board can stay (I don't know if it's indeed for pincushion without seeing it). The neckboard can be swapped.

Okay, so I did swap the neckboard and viola! The tube came to life.  Got some serious adjustment and picture issues but I am dialing it it.  Picture is great vertically, it is a little short horizontally.  The biggest thing i noticed was no Red color, and a serious "bloom" in the middle but only when there is a white object there, like the big golf ball.  Ill try to get a picture of it up.

But hey I consider that a win, nothing blew up!  Im look forward to trying to get this other board with all the new parts in it and going.

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #36 on: March 26, 2020, 07:47:08 pm »
The saga continues.

So I removed Q1 and Q201 from the Red circuit and swapped them with the same from the green circuit to test to see if that is where the failure is.  Unfortunately still no red.  Solder joints look good, no broken traces that I see.  Right now, looking like the tube, which stinks. 

I did mess with the red pots on the neckboard and turned them all the way up and could kinda get a rust red all over the screen.  Like a faint background. Anyone know if that is a particular indicator?

Off to start researching a tube swap!

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #37 on: March 27, 2020, 05:19:28 am »
could be gun, momentary short the red gun to ground- that will prove tube

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #38 on: March 27, 2020, 05:28:41 pm »
could be gun, momentary short the red gun to ground- that will prove tube

Thanks Grantspain, I have read about the "ground the red gun" but honestly I am uncertain what to take to ground.  Any clarification would be very much appreciated.

Back to Project 1: got the replacement capacitors in today and got them installed to the original board.  Looking good.  Also got the new STR30130 in and installed.  Finally getting 130vdc with Prin's isolated bulb test.  Nice!  I am now moving to the expanded traditional bulb test that brings in more components.  Fingers crossed, I will post the results!

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #39 on: March 27, 2020, 05:36:31 pm »
Woohoo getting 130vdc with full bulb test.  Going to reinstall the new HOT and see what happens.  Fingers crossed again.

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #40 on: March 27, 2020, 06:22:22 pm »
locate the red gun pinon the crt socket  and short a bit of wire from that to a cap ground, if you screen goes bright red then gun is ok

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Re: Troubleshooting a WG 25k7191 no picture blowing fuse
« Reply #41 on: March 27, 2020, 06:30:13 pm »
Well... WOOHOOO! the original board, with the new parts works! and RED is back! Man this is awesome  :cheers:

Now to start dialing it in, etc., but everything is working as expected.  My guess is that it was the grounded C37 that was the culprit.

BIG thanks to all you guys, for the vast knowledge and the super helpful posts.  Thanks guys!!!