Build Your Own Arcade Controls Forum
Main => Monitor/Video Forum => Topic started by: SpaceGod on September 14, 2016, 04:21:57 pm
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I have a problem with a sharp imvge si-727r-ds and the chasis is getting power but the crt neck is not getting the orange light. The chassis also beeps. The game still has sound so the psu still works. Of anyone could help I would be very thankful.
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http://www.arcade-museum.com/manuals-monitors/Sharp%20Image%20SI727RDS%20Monitor%20Repair%20Guide.pdf (http://www.arcade-museum.com/manuals-monitors/Sharp%20Image%20SI727RDS%20Monitor%20Repair%20Guide.pdf)
the tweeting is usually an indication that something in the power supply has shorted or is a very high load and the power supply is repeatedly starting up and shutting down (due to overcurrent protection) it makes a tweet tweet tweet or sometimes a tick tick tick kind of sound.
usually the high voltage caps (c412 c421 c93 c817 c818 c908) or a shorted horizontal output transistor (Q402) is the cause of the shutdown
if this monitor has never been worked on, I suggest you get a cap kit for it and replace them. They are probably nigh on 20 years old. Capacitor lifetime ratings are measured in hours, with GOOD quality caps being in the 5000 hour range.
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See that's was what I was thinking it was because the caps are very old and the chassis had an flyback replacement so it can't be that
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http://www.arcade-museum.com/manuals-monitors/Sharp%20Image%20SI727RDS%20Monitor%20Repair%20Guide.pdf (http://www.arcade-museum.com/manuals-monitors/Sharp%20Image%20SI727RDS%20Monitor%20Repair%20Guide.pdf)
the tweeting is usually an indication that something in the power supply has shorted or is a very high load and the power supply is repeatedly starting up and shutting down (due to overcurrent protection) it makes a tweet tweet tweet or sometimes a tick tick tick kind of sound.
usually the high voltage caps (c412 c421 c93 c817 c818 c908) or a shorted horizontal output transistor (Q402) is the cause of the shutdown
if this monitor has never been worked on, I suggest you get a cap kit for it and replace them. They are probably nigh on 20 years old. Capacitor lifetime ratings are measured in hours, with GOOD quality caps being in the 5000 hour range.
would it be better to just but a new chassis? Or will the monitor be crisp with the capkits
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you are most assuredly not going to find a new chassis... pretty unlikely in decent used condition that is in any better shape than what you have got already.
Every manufacturer stopped making CRT monitors a number of years ago when LCD's and plasma displays started hitting the market. Deflection IC's, horizontal output transistors, and video amplifiers used in CRT's are becoming harder and harder to source. Nobody makes CRT monitors, so nobody is bothering to make the parts.
if your chassis is in decent condition...and nobody has messed with it... Likely a "capkit" is going to set things right again. while I can't 100% assure you it will (i mean there are 1000 parts on there that could possibly go bad.) it's one of the most common problems.
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It was to be my hot because I'm getting a reading of 012 on my multimeter
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it's really hard to properly test a HOT, mainly because they can test fine (even with a proper transistor tester) and still fail under load...or even test bad, but work okay.
a majority of modern chassis HOT's have diodes built in that can throw off any reading you get.
it's possible it's gone bad on you, but don't discount it not being the issue.
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I am Probably going to change the HOT and the CAPs in question just to be safe the caps and the HOT has been in there for a long time. and also i have another question. i has looking in the pdf you linked me and it said a 2sc5150 should be used but someone put a 2sc5143 in its place. when i but the HOT should i use the recommended transistor or a 2sc5143?
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it's really hard to properly test a HOT, mainly because they can test fine (even with a proper transistor tester) and still fail under load...or even test bad, but work okay.
a majority of modern chassis HOT's have diodes built in that can throw off any reading you get.
it's possible it's gone bad on you, but don't discount it not being the issue.
I am Probably going to change the HOT and the CAPs in question just to be safe the caps and the HOT has been in there for a long time. and also i have another question. i has looking in the pdf you linked me and it said a 2sc5150 should be used but someone put a 2sc5143 in its place. when i but the HOT should i use the recommended transistor or a 2sc5143?
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Counterfeit parts are going common this days, so it's not always a good idea to replace possibly good genuine parts with new parts.
You should perform a bulb test: replace the HOT with a 70-100W bulb lamp (the old tungsten filament, not the newer energy save bulbs) by soldering it between the emitter and collector; this way you esclude the HOT (obviously) and the flyback (EAT). If the monitor stay lit, HOT or EAT are your problem.
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I know what messed up the chassis. The previous owners didn't ground the monitors AC current to to the chassis metal frame would that help me penpoint the definitional part
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same hot
stick with shawn
ed
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it's not a super big deal if the frame is not grounded (sure it's hazardous to life if there is a failure) but not really something that would cause a failure.
you are ticktickticking so that tells us most of the power supply IS working... so right there you have half the battle.
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it's not a super big deal if the frame is not grounded (sure it's hazardous to life if there is a failure) but not really something that would cause a failure.
you are ticktickticking so that tells us most of the power supply IS working... so right there you have half the battle.
Ok that's for clearing that up. And also a black wire that was should be on the chassis was came off it before I got it. Its supposed to be close to the flyback think I'm trying to see what do i do with it. Here is a picture
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A ticking sound is a classic indication of a busted flyback.
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A ticking sound is a classic indication of a busted flyback.
not necessarily. all a ticking sound is, is an indication that there is an overload condition on the output side of the SMPS.
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A ticking sound is a classic indication of a busted flyback.
not necessarily. all a ticking sound is, is an indication that there is an overload condition on the output side of the SMPS.
yeah i think its the HOT but i said forget it and i am buying a whole cap kit with HOT and flyback from bob roberts and show this old chassis some love ;D
but i still need to find out where that short black wire goes in on the pcb
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it's kinda dark, but it looks like it has a toothed ring crimped on it. should be a ground. could be on the neckboard and screws onto the frame.
check around the outside of the chassis and neck board for remnants of the end of the wire...maybe a hole or possibly just a solder blob on the back somewhere.
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I am going to check that out now and i just bought the whole kit from bob roberts so ill just change everything :cheers:
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i just got my cap kit and hot i will show everyone when im done
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it's kinda dark, but it looks like it has a toothed ring crimped on it. should be a ground. could be on the neckboard and screws onto the frame.
check around the outside of the chassis and neck board for remnants of the end of the wire...maybe a hole or possibly just a solder blob on the back somewhere.
Ok I soldered the back ground pin back and changed all the high volt caps and now I don't get the clicking but still no picture, so I'm getting progress. when I get out of class I'll change everything
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Have you tried reflowing the power headers? Sometimes it helps to take a look at the solder for cold joints, I've saved a few CRT's by just reflowing some of the major pins.
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ok i changed all the caps and hot and flyback and its still not working. i dont know what it could be now?
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is it still ticktickticking?
could be faulty vertical deflection IC. had to say. Gonna need to start disabling systems voltage rails to see if disabling one of them makes it "come on"
usually on the output of the SMPS transformer all the voltages come out and run into diodes then maybe ferite inductors before it hits the filter caps.
lifting out the diode for the rail will effectively disable that system. you are definitely gonna need to be able to read a schematic to do it properly though.
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is it still ticktickticking?
could be faulty vertical deflection IC. had to say. Gonna need to start disabling systems voltage rails to see if disabling one of them makes it "come on"
usually on the output of the SMPS transformer all the voltages come out and run into diodes then maybe ferite inductors before it hits the filter caps.
lifting out the diode for the rail will effectively disable that system. you are definitely gonna need to be able to read a schematic to do it properly though.
No there is no more ticking I think when I was soldering the fly back that the solder dripped into theflyback side
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Also pieces of the HOT trace came off. I got it to solder on the hot and bring the solder to the remaining trace
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er
what are u using for a soldering iron ?
ed
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er
what are u using for a soldering iron ?
ed
a $5 radio shack soldering iron