Sharp XM-2001N Info Request

WAGDAG

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Hi there,

I have a couple questions regarding the XM-2001N that I would appreciate some info on. Sorry that this is a bit long, but I wanted to let you know what I have and haven't done so far.

This weekend I finally got my project Blasteroids to coin up. Unfortunately, it was playing blind. It had no neck glow and input voltage was correct. The chassis was filthy and I believe the monitor had never been out. After some compressed air and a dust cloud, I didn't see any bulging caps, obvious charred traces or components, and fuses were good. I thought I saw a hairline crack on the flyback so I went ahead and replaced that with a new spare I had kicking around. After I removed the old flyback, I really went after it with a brush to see the damage and then I noticed it wasn't a crack at all. It was a tiny string of glue that they used to secure the bigger caps. Don't know if I should be happy or sad about that discovery. It really looked like a crack even when removed! So, let's call this monitor XM1. I removed another XM-2001N from my Vindicators and stuck it in Blasteroids and the game fired up just fine. Let's call that one XM2.

XM1- replaced flyback, will order Security's cap kit, and gave it a good reflow. Found several cold solder joints at large resistors R605, R607, and R704. Removed them to test out of circuit and I'm glad I did. There were lifted traces that were very brittle under the solder. Bridged those traces as needed. Gave the width coil new solder for good measure. Stuck my Sencore CR70 onto the tube and found no shorts on any gun, but cutoff or emission didn't even move the needle off the pin on all guns. Did a rejuv and emission is now reading very good, but cutoff still hardly moves the needle. Did an auto restore on all guns and the same results. Left it alone after that as not to push my luck. I read that a tube with bad cut off and good emission will result in a picture with poor contrast.

XM2- This monitor has worked well since I capped it and found the width coil had desoldered itself. It is very crisp, but I always thought the Vindicators just used a really weird green palette. To be honest, this game doesn't see much play.

So, I play a few games of Blasteroids and think to my self...damn, that's a lot of red, green, and yellow. No blue! Research a bit and crank up blue bias to max. Mess around with all neck board pots to no avail. Can almost see a touch of blue at max, but it's pretty much non existent. The blue bias pot does effect the screen, but more like a brightness control. The game image looks pretty darn good for missing a third of the color.

So, I tested the tube on XM2 and find all tests pass with very good results. It's not the CRT.
Must be something on the chassis.

Whew...thanks for hanging in there this long.

Next steps:
Cap kit on XM1, then test it out with original CRT. If it works, great. Then I can mate it to the CRT presently in XM2 to see if I get a fully working chassis / tube combo.

Next, try and see what's up with blue circuit on XM2 chassis

Finally...the questions!

What else should I check for on XM1 before I fire it up with fresh cap kit and flyback?
Are there known problem areas or components to check or replace while it's out?

Could it be that the original XM1 tube that tested bad on emissions couldn't draw enough current so it caused the chassis to shut down? Sorry if that's a silly question, I'm trying to learn what's going on under the hood of these things. If low emission can cause shut down, then maybe it didn't have a different failure and will come back to life using the rejuved CRT or the tube that tested good from XM2.

Is this CRT, Sharp 510YWB22, a candidate for being swapped out with a TV tube?
Anyone have any luck with a tube swap with / without yoke swap?

On XM2, any pointers where to start troubleshooting the blue gun issue? Forgive me for not having looked at the schematic yet. I am trying to find a readable copy to dig into. All this took place over the past weekend and I ran out of time. I am holding off ordering parts in case someone suggests any additional components to replace.

Any info would be greatly appreciated!

Have a good evening everyone and thanks for all the info you guys put out here for lurkers like me to reference and learn from.
 
In my experience a low/shorted/dead color will not cause a monitor to go into shut down.

I'm almost certain that a xm200in has the same neck pinout as a k7000 19" monitor. Which is good for tube swap purposes. Heck you may even find a TV on the side of the road that has an equivalent yoke so you don't need to swap the yoke.
 
510YWB22 is a CR-31 tube, very common in 90s-00s black plastic TVs. The electrical connections are all compatible, but you might not be able to get acceptable convergence. Unfortunately, there's no way to know for sure without trying.
 
I just purchased a blasteroids with this monitor, it was missing the red. Discovered there is a video invert switch next to the RGB connector and if I wiggled the switch I would get red, and loose the blue. Bad Switch!
 
Had the same issue but with green after new caps and a flyback. I could not for the life of me figure it out. Voltage was good, guns were good, resistors appeared to be good. I did try switching the switch during troubleshooting but after reading this, went at it a bit more aggressively and it worked. Life saver!

I just purchased a blasteroids with this monitor, it was missing the red. Discovered there is a video invert switch next to the RGB connector and if I wiggled the switch I would get red, and loose the blue. Bad Switch!
 
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