Hi thank you so much, for sharing you knowledge and experiences. Could you please help me out. To fix my K7400? I was doing a recap, but when I started working on the neck board, I notice that it has some missing components. I tried to look on internet the schematic of it to place the missing components, yet I didn’t find them. Anyway, I wonder if you could tell me the specifications of the following components? R511 R512 C519 C521
Weird with the soldered pincushion board. I thought they were only for 27" 7500s. I am far far from any kind of expert but I thought I heard that. Clearly this is a 25" and a 7400 so bad info in my meager brain lol. Good digging to find the issues and great repair as always, I as always eagerly await the next repair!
Just found your channel today. I used to run a channel called retro games party. I mainly fix pcb’s but understand monitors a fair bit. Have you changed yokes to run the k7xxx on the polo tube or just the connector? Both should be low impedance yokes I think. The polo’s are very common here in the UK as are the Hantarex 900/E and 9000.
Hi Mike, really awesome videos! I'm learning a lot! One question about the H.O.T. With it out of the circuit i am reading continuity on the PCB between the pads for the outside legs(base and emitter), Should I be? I'm wondering if this is what killed the H o T. Again, thanks for doing these great videos! Brian
Yes. Continuity on the outside legs is normal. If you have continuity between either outside leg and middle leg with the HOT removed, that is an issue. Usually means the big poly caps on the other side of the heat sink or the diode under them are/is shorted. If you are not using the FJL6920, I would highly recommend that over the 3688s.
Is your sync on pin 10 only? Is it an H.Hold or V.Hold issue? Are you using a standard res signal/game? Are you adjusting the H.Hold pot on the chassis?
Hi Mike. Im dealing with a k7500 that has a power supply problem. b+ votage at over 200 with the light bulb test. R104 tests good. I replaced smps chip. I replaced voltage mosfet. I replaced b+ pot and high voltage shutdown pot. Do ya know what i am missing? Thanks! Curt
Hey Curtis. I’d start by checking for shorts and bad joints/cracks around the transformer. I’ve also seen the little poly caps around the SMPS chip go bad before and cause issues like this.
Thanks. I should mention that the b+ pot does not allow me any control of the voltage either. I have several parts chassis that I could swap in those two little yellow caps near the SMPS. When I powered up this chassis at first on a tube I had voltage over 300. I have never seen that before. The flyback powered up as well and a very loud energetic power up.
Hi Mike! I have a Toshiba D29CR55. They were used mostly for Dance Dance Revolution cabs. The monitor was running flawlessly and all of a sudden, the display went blank. Some people told me that the issue may be the HOT, stumbled upon your video. Should I test all caps and try to find the culprit that caused this?
Is it completely dead? No ticking? No signs of life? Fuse good? Not familiar with that monitor so I can’t say what to check off hand but I’d start with the basics and a good visual inspection and go from there.
i was wondering if you have a email it a way to bounce questions off you or even a bussiness i could maybe send you my board im at my wits end changed lots of parts and watch lots of your videos i have a u5000 and i have a b plus at around 300 VDC pretty sure the pot tested good.
300V? I assume you're measuring at the correct test point? What happens if you remove the HOT? Do you still get 300V? R104 in spec? What is the B+ when doing the light bulb test?
@@MikesArcadeMonitorRepair R104 reads just under 10 so im assuming its good light bulb test works i have not done this test with out the HOT in the game I've installed a new HOT as well as a new Q101 , Q703 , Q705 and Q708 when i got this board the fuse was blown and the HOT was blown. I've also done a full cap kit and replaced a new resistors from watching piles of your videos.
@@MikesArcadeMonitorRepair okay thanks pretty new to this first repair attempt i did get a shock from the flyback lol does that mean its working? any good places to buy one? im up in canada or do you offer board swaps at all?
Another flippin awesome repair sir !
Hi thank you so much, for sharing you knowledge and experiences.
Could you please help me out. To fix my K7400?
I was doing a recap, but when I started working on the neck board, I notice that it has some missing components.
I tried to look on internet the schematic of it to place the missing components, yet I didn’t find them.
Anyway, I wonder if you could tell me the specifications of the following components?
R511
R512
C519
C521
Weird with the soldered pincushion board. I thought they were only for 27" 7500s. I am far far from any kind of expert but I thought I heard that. Clearly this is a 25" and a 7400 so bad info in my meager brain lol. Good digging to find the issues and great repair as always, I as always eagerly await the next repair!
This is a rarer 23k7401 from Atomiswave cabs.
Outstanding!
So the HOT shorted when the last person tightened it down?
Just found your channel today. I used to run a channel called retro games party. I mainly fix pcb’s but understand monitors a fair bit.
Have you changed yokes to run the k7xxx on the polo tube or just the connector? Both should be low impedance yokes I think.
The polo’s are very common here in the UK as are the Hantarex 900/E and 9000.
Polo/7000/7400/2000/5000 (standard res selection only) are all compatible with each other and are drop in replacements.
Hi Mike, really awesome videos! I'm learning a lot! One question about the H.O.T. With it out of the circuit i am reading continuity on the PCB between the pads for the outside legs(base and emitter), Should I be? I'm wondering if this is what killed the H o T. Again, thanks for doing these great videos! Brian
Yes. Continuity on the outside legs is normal. If you have continuity between either outside leg and middle leg with the HOT removed, that is an issue. Usually means the big poly caps on the other side of the heat sink or the diode under them are/is shorted. If you are not using the FJL6920, I would highly recommend that over the 3688s.
Cool, thanks for the quick reply Mike! I'll need to find the FJ's.
You’re welcome. See below…
www.arcadepartsandrepair.com/store/integrated-circuits/transistors/fjl6920-high-output-transistor/
The new higher amp HOT did the trick Mike. Now I'm trying to figure out why it won't sync. No matter what I adjust.
Is your sync on pin 10 only? Is it an H.Hold or V.Hold issue? Are you using a standard res signal/game? Are you adjusting the H.Hold pot on the chassis?
Hi Mike. Im dealing with a k7500 that has a power supply problem. b+ votage at over 200 with the light bulb test. R104 tests good. I replaced smps chip. I replaced voltage mosfet. I replaced b+ pot and high voltage shutdown pot. Do ya know what i am missing?
Thanks!
Curt
Hey Curtis. I’d start by checking for shorts and bad joints/cracks around the transformer. I’ve also seen the little poly caps around the SMPS chip go bad before and cause issues like this.
Thanks. I should mention that the b+ pot does not allow me any control of the voltage either. I have several parts chassis that I could swap in those two little yellow caps near the SMPS. When I powered up this chassis at first on a tube I had voltage over 300. I have never seen that before. The flyback powered up as well and a very loud energetic power up.
Hi Mike! I have a Toshiba D29CR55. They were used mostly for Dance Dance Revolution cabs. The monitor was running flawlessly and all of a sudden, the display went blank. Some people told me that the issue may be the HOT, stumbled upon your video. Should I test all caps and try to find the culprit that caused this?
Is it completely dead? No ticking? No signs of life? Fuse good? Not familiar with that monitor so I can’t say what to check off hand but I’d start with the basics and a good visual inspection and go from there.
@@MikesArcadeMonitorRepair The neck still has some glow, it ticks once only when it’s powered on. But no picture or luminosity on the display.
i was wondering if you have a email it a way to bounce questions off you or even a bussiness i could maybe send you my board im at my wits end changed lots of parts and watch lots of your videos i have a u5000 and i have a b plus at around 300 VDC pretty sure the pot tested good.
300V? I assume you're measuring at the correct test point? What happens if you remove the HOT? Do you still get 300V? R104 in spec? What is the B+ when doing the light bulb test?
@@MikesArcadeMonitorRepair R104 reads just under 10 so im assuming its good light bulb test works i have not done this test with out the HOT in the game I've installed a new HOT as well as a new Q101 , Q703 , Q705 and Q708 when i got this board the fuse was blown and the HOT was blown. I've also done a full cap kit and replaced a new resistors from watching piles of your videos.
I would suspect a bad flyabck at this point then. At least it would need to be ruled out.
@@MikesArcadeMonitorRepair okay thanks pretty new to this first repair attempt i did get a shock from the flyback lol does that mean its working? any good places to buy one? im up in canada or do you offer board swaps at all?
@@MikesArcadeMonitorRepair also wonder if I test b plus with the jumper removed correct?