asteroids monitor needs assistance

mk3u2012

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after removing the speed mod on the pcb i put in the 161 ic off the daughter board that was socketed with no issues. but after reinstalling and powering up i got a blank screen unless i put in test mode which i got the same error screen as before with the dashes. after being on for a few minutes i started to smell burning. i was in the back of the cab and it was coming from the monitor area not down by the board. what i would like to do is properly bulletproof the monitor. i have worked and discharged many raster monitors but never a vector and if i remember correctly the discharge process is different and even the tool used is specific? let me know if there is a write up or doc that encompasses all of this, and ill be happy to take any advice here as well.
thanks
blake
 
discharging of the vector is use a HV probe.

most of the people i sell the kits to are doing the caps and sometimes filters and connectors (reflow).
 
what i always do with one of these monitors:

- remove old solder and REFLOW all header pins, the pots, and anything that looks questionable
-meter across all fuse holders
-check chassis mounted transistors are working properly and not shorted to monitor frame. replace as needed making sure they are isolated from the monitor frame. make sure not to use a conductive thermal paste (like arctic silver).
-cap deflection board and HV cage (very few caps, quick job)
-remove R100 and R101 and replace with heavy gauge wire (this is controversial to some, but it was a factory-recommended mod)
-visually inspect the harnesses connecting the chassis mounted transistors to the boards. reflow any questionable joints at the sockets. repin the connectors unless they are factory-snug (i replace the molex connectors as well usually).

that fixes 90% of the monitors i've seen and it only takes about a half hour
 
discharging of the vector is use a HV probe.

most of the people i sell the kits to are doing the caps and sometimes filters and connectors (reflow).

ive read about putting resistors in series to slowly bleed off the current. is this recommended? and are the $20 hv probes on ebay capable of doing the job? ive read it needs to be able to handle 30k volts?
thanks
blake
 
what i always do with one of these monitors:

- remove old solder and REFLOW all header pins, the pots, and anything that looks questionable
-meter across all fuse holders
-check chassis mounted transistors are working properly and not shorted to monitor frame. replace as needed making sure they are isolated from the monitor frame. make sure not to use a conductive thermal paste (like arctic silver).
-cap deflection board and HV cage (very few caps, quick job)
-remove R100 and R101 and replace with heavy gauge wire (this is controversial to some, but it was a factory-recommended mod)
-visually inspect the harnesses connecting the chassis mounted transistors to the boards. reflow any questionable joints at the sockets. repin the connectors unless they are factory-snug (i replace the molex connectors as well usually).

that fixes 90% of the monitors i've seen and it only takes about a half hour

awesome! thanks for the details. when you say meter across im assuming your looking for continuity? what type of paste do you use?
thanks
blake
blake
 
this is what i use to discharge vectors, in line with my standard discharging tool (aka a screwdriver and jumper wire). 10 100k ohm resistors in series housed in an empty magic marker tube.
 

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this is what i use to discharge vectors, in line with my standard discharging tool (aka a screwdriver and jumper wire). 10 100k ohm resistors in series housed in an empty magic marker tube.

how do you attach it?
thanks
blake
 
discharge tool attaches to the ring on the end of the 1 Mohm resistor pack, then the resistor pack attaches to the frame of the monitor.

i've been hearing debate for the last 10 years that doing this is or isn't necessary, but it's cheap and takes 2 seconds to do it, so i do it.
 
ive read about putting resistors in series to slowly bleed off the current. is this recommended? and are the $20 hv probes on ebay capable of doing the job? ive read it needs to be able to handle 30k volts?
thanks
blake

i personally use a 40K HV probe on everything and they aren't very expensive for a good quality one and i use it on every monitor type. watch ebay usually 30-60 bucks.
 
discharge tool attaches to the ring on the end of the 1 Mohm resistor pack, then the resistor pack attaches to the frame of the monitor.

i've been hearing debate for the last 10 years that doing this is or isn't necessary, but it's cheap and takes 2 seconds to do it, so i do it.

yea i just read a couple of topic debates on the matter and it seems to be split. i agree that for the price and time its worth doing.
thanks
blake
 
yes just test for continuity across the fuse holders. i just use radio shack thermal paste, nothing special.

Make 100% sure you use nonconductive paste. No silver shit. And tbh I've heard it really won't hurt the hv diode to just screwdriver discharge. Most of the current is gone the small amount left is unlikely to damage the diode and why the hell would it try to travel to ground through the diode and kill it you give it a good path. That's what ole bob roberts said. Do what you want tho.
 
after removing the speed mod on the pcb i put in the 161 ic off the daughter board that was socketed with no issues. but after reinstalling and powering up i got a blank screen unless i put in test mode which i got the same error screen as before with the dashes. after being on for a few minutes i started to smell burning. i was in the back of the cab and it was coming from the monitor area not down by the board. what i would like to do is properly bulletproof the monitor. i have worked and discharged many raster monitors but never a vector and if i remember correctly the discharge process is different and even the tool used is specific? let me know if there is a write up or doc that encompasses all of this, and ill be happy to take any advice here as well.
thanks
blake

I grab the cup with one hand and take it off.. i do wear latex gloves though.
 
just got around to making my hv probe (modeled after scoots). thought id show.
thanks
blake
 

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