Main > Monitor/Video Forum
Wells Gardner D9200 - Horizontal Collapse?
Rocketeer2001:
Well I have some new info! I was in contact with a customer service rep at Incredible Technologies and he said that this mythical "Monitor Scaler Board" I need to make BBH2 run in CGA mode was a device made by Averkey, and that was all he knew. I did a web search and found the AVerMedia AVerkey iMicro PC to TV Converter:
https://www.bhphotovideo.com/c/product/677824-REG/AverMedia_DKEYIMID2_AVerKey_iMicro_PC_Mac_to_TV_Converter.html
It has a VGA output that's supposedly an RGB SCART, but the specs don't say if the output signal is in 15kHz @ 60Hz or something else. I emailed AVerkey to see what they could tell me. If this works, that would mean this is a scan converter, right? Then I could go back to using the TV as a monitor and doing the RGB mod, or at the very least I could get S-video out of it, so that's a step in the right direction.
Not sure if this converter would mess up the light gun functionality though.
tiger1900:
Hi Rocketeer2001!
I joined this forum to ask you a question.
I just happened to be working on the same D9200 monitor. I fully recapped it, reflowed all the boards and it worked great, but it would start making a arc noise every so often; after heating up, it increased. I found if you take the factory sealed VR901 and turn it counter clockwise (raising the resistance) the arcing stops (this also scales the picture larger...??? - note: I wrote down the original value before tweaking the pot). This is also demonstrated in one of the YouTube videos you linked.
Reason why I said "it worked great" was because I decided to do some poking around the board. My monitor is outside of a cabinet, and using a temperature gun I clocked the 2SC5144 getting close to 140f (60c). around this temperature I started getting wacky horizontal happenings (4 hours outside of the cabinet in an 85f (29.4c) ambient temperature room).
I decided it needed new thermal paste. So I took some MX-4 I had sitting around, took out the screw... that's when I noticed the screw for my 2SC5144 (Q418) wasn't tight at all. Without desoldering it, I bent the chip out of the way, used an alcohol wipe to remove the old white silicon, which was totally dry and cracking off both sides of the gray silicone pad, caked on some MX-4 on both sides and replaced it, this time cranking down the screw.
I restored power, and I got a squealing sound now from the monitor that was originally dead silent. Hmmm, was there a reason it was on there loose?
I loosened the screw... still squealing, and a burning smell (still in contact with heatsink); I then powered it up with the chip bent away from the heatsink (cleaning position) and the squealing stopped, it was back to normal. Was this a cracked solder joint? (nope).
I tried to put the screw in loose again, the squealing returned (each of these time, the monitor was only powered for a short period before disconnecting). Lastly, I pulled it away from the heatsink again, and when I powered it up, a FLAME shot from the screw hole! (anyone reading this, yes that whole thing was irresponsible, but it could survive momentarily without a heatsink, a flame shouldn't had shot from it... as far as I know).
I thought to myself, maybe I damaged the casing, cranking it down. The heatsink is just a plate, maybe a burr dug through the silicone pad?
After cleaning the chip, I found where the flame shot out. I felt the heatsink hole and there is a burr around the hole. I wonder if this had anything to do with it getting damaged? I wouldn't think bending the leads would had done it.
Question: Every time you replaced the 2SC5144, did you more than "snug" the screw for Q418 also?
I think I read in a post that you were getting B+ (170v measured from either side R854) and the majority of your components were fine before the catastrophic failure.
Even though this 2SC5144 had a flame shoot from it, it still tests PERFECTLY! Both in a device like the one you shared, and the way Princess Prin Prin demonstrated.
I ordered a new 2SC5144 and will install it later this week. I plan on deburring the hole and just snugging the screw this time. I feel mine was already on its way out, but my mishandling helped it a bit.
Testing the surrounding circuit. Everything is fine. I cut power every time there was an oddity, and only left the screeching going until I could identify the noisy component.
I think, I'm only the 2nd person to work on this chasis. I'm sure I was the first to touch the 2SC5144 since factory.
Rocketeer2001:
Tiger, sounds like we're on a similar unfortunate journey.
Did your Q418 have a mica sheet insulator between it and the heatsink? As I found out, it's a necessary part to prevent arcing between the component and the heatsink. Even though mine was arcing, upon removal it tested fine so I put it back in. It doesn't arc anymore but the whole monitor doesn't do much anymore other than make clickity noises.
I didn't crank down the screw. I only snugged it down enough so that the back of the part was sitting flush against the heatsink; just enough to make sure it would make a good heat transfer. I wouldn't think it should ever be too loose, otherwise it wouldn't keep Q418 flat against the heatsink.
It's possible your burr was digging into the back of the 418, just enough to cause it to arc, similar to how my screw might have dug into the edge of the hole for my 418 and was arcing. The part tests fine, but maybe it's somehow damaged. I might have the same issue, but unless I know for sure I don't feel like throwing more money at it in parts.
Keep us appraised of your progress!
lilshawn:
just an FYI, a component can test fine at the low voltages used by a test machine, but fail when full B+ voltage is applied.
if your chassis is giving the old tick tick tick, it's the SMPS's way of telling you it's output overloaded and it's trying over and over to start up. (just in case the first time it was a large, empty capacitor that needed some more time to charge up.) but a shorted component (like a shorted capacitor or diode that is connected to ground) can also make the SMPS do this.
look at your schematic at everything connected to B+ and see what you can remove to "cut off" part of a circuit. often you can "cut" a circuit down into 3 or 4 separate sections or pieces... by removing resistors, inductors, transformers or diodes. if "cutting out" a section, then applying power results in the main SMPS firing up and not ticking, then the section you cut out has the fault. see attached for some examples. your specific application will vary.
use caution when removing components... you are only powering on the chassis long enough to see if the SMPS now has the short/overload removed from circuit. 1 or 2 seconds max. any longer and you risk blowing up more components as systems attempt to work without their support circuits.
tiger1900:
Thank you @lilshawn for isolating the circuits in the drawing.
I also agree, even though this original 2SC5144 (Q418) tests fine, I'm replacing it (especially since it shot fire). I've had a similar occurrence where a component tested fine outside of a circuit, but not while in operation. @Rocketeer2001 I'm reusing the silicone isolator, after a cleaning, I found it to be in good physical condition.
Latest: Anyone know where I can find a genuine 2SC5144? I'm in the USA and I can't decipher if a seller has an actual genuine supply. :dunno
Reason: I just received an order, and comparing these to what was factory installed, there's a huge difference in their quality and appearance. Out of the two received, one tested bad out of the box.
Has anyone used these? Are they fake? Anyone recommend where can I get a couple of good ones?
Thanks for your assistance.