Monitor Out

[mkd3b]

Ok  Here we go   Have dabbled with Slots, Pins, Jukes and the like now I Have a Centipede game By atari that I aquired for a good price (Free)   Had nothing when plugged in for first time now have some game play sounds and function but no screen at all.  What are my first concerns with these older monitors, really dont want to catch a jolt of any kind from it. Dont know the last time it was operational.  IS there something simple to check before I think about having it sent out fro a checkup.  Thanks ArtD

[jay]

Run your finger across the screen (when it is on) and see if you feel static. Another test is to turn the machine on and turn off the lights in the room - you should see a glow from the phosporous if its working.
If you have static you have high voltage. A common problem in older TVs/Monitors etc is the loss of the high voltage transistor.

It is also possible that the monitor is not even plugged in. Because of the way these monitors swing up for maint it is not uncommon for the power feed to be lose, disconnected, damaged etc.

If you have static and no picture it could be that the cable from the board to the monitor is unplugged, semi-unpluigged or coroded. For the same reasons as noted above.

[mkd3b]

Ok its been a few days  Have been a litttle busy     Took out the chassis and have noticed that someone has replaced the Fly back and a few but not all capacitors.  Also took readings on the transistors  Horizontal output trans seems to be bad from the .041 reading that I have   ?????   regulator trans on other side seems good with .597 reading ????..   Im really just wingin it here  Very much a newbie on this Old Crt   Have the soldering  skills to tackle the boards just not sure if Im addressing the right things yet.  Had nothing at all when first aquired game Have ssound and some game play but no picture.   There is also a noticeable hum inthe speakers when the game is over and the player 1 or 2 lights are on or off in standby mode, not sure if this could help for the crt issues.     Jay if you read this are you talking about the Horzntal output transistor when you mention High voltagfe transistor,  are they one in the same?

[badbaud]

Jay's not here man!... or was that Dave?
The horz output transistor will read shorted from emitter to base, it has a very low resistance there but emitter to collector should not read shorted. It is very important that you check for the presence of any high voltage by running your hand over the screen while the game is on and checking for any high voltage. If there is no high voltage start at the input side of the monitor and work your way forward. Is there AC going to the monitor? then, is there a fuse on the monitor that prevents this AC from powering the monitor. Then, if the fuse in not blown is there a AC to DC circuit on the input that is providing DC to the electronics that may be bad. The make and model of the monitor would be the first step in getting more specific help with your problem.

[mkd3b]

Electrohome G07 19"  Have the monitor ot right now checking the board and components.  The Hot out of the board still reads .041  The emitter and collector thats foreign to this newbie but Im sure they are the two posts just not sure which is which.  Ill have to put it all back together and see what happens.  But I still think the Hot Is Probably bad from a prior post I read.

[badbaud]

emitter and base are the two outside leads, the center lead is the collector which drives the FBT. No low resistance from the center lead to either of the two outside leads means the HOT is probably good.

[mkd3b]

Oh now Im a little stumped  the Thing Im calling the HOT has 2 posts not three and is mounted on the chassis not the board  Am I wrong with the component?

[badbaud]

That's a TO-3 type case. The collector is the metal body of the transistor. If you turn a TO-3 over and have the two leads to the left and closest to the mounting hole the base is on the bottom and the emitter is on the top and the collector is the body. The resistance will be very low between the two terminals (emitter and base) but high from the collector to the base or from the collector to the emitter.

[mkd3b]

Touched up a few conections that didnt look great cleaned up the boards a bit, some really exceesive use of solder on there lots of flux residue from who ever had the machine last.  Put everything back together  and........ Nothing changed    No static or Glow to notice   Found a flow chart online to try and trouble shoot monitor   we'll see what happens  Probably best betr to change out all Caps I suppose or is there something else to cause no Static or High Voltage



Was Just checking on some things with the flow chart   Got some action But not good action    Noticed a  little arcing from the bottom of the board now  when swithing on will have to  recheck some fuses now i suppose.  Will pull out chassis  again to investigate bottom of board   Had some pretty high dc voltages as well   153.5  on R1 resistor and higher 161.4 at other end.  Checked dc at   xo1 also was  153.3

LATEST UPDATE     PROJECT EFFECTIVE IMMEDIATLY     OVER FOR NOW
Stupid newbie move working in confined spaces not good set monitor down for troubleshooting went to move cabinet to hook up conections and bam bumped neck board with cabinet and cracked neck tube could hear the air swooshing as the vaccuum was lost    I am Done  Right   Just checking is this a repairable  screw up or not worth the trouble.

[badbaud]

All of us shop type people have used tubes laying around. Most have burn in on the screen but better then nothing. Have you contacted Happ controls to see if they can sell you one of those fancy flat screen replacements?

[mkd3b]

Not really done much as of yet was trying to figure out why the monitor was out in the first place.  I assume everything is fine because of hearing game sounds with no picture.  Dont need to go crazy on cash  not knowing if the machine has a board issue as well.  Is the board in control of the monitor coming on or is that Just for the graphics.  If I start to spend money on parts  it could be for nothing  Would be nice to be able to get a local possibly to put in a known working monitor to check out.  What are my options as far as converting to a updated monitor is it generally plug and play or am I looking at more mods.  Just wingin it still   The  game doesnt owe me anything yet but I hate to see it go to waste  Know What I Mean.  The boss is already tellin me to get rid of it but I just Cant do it

[jay]

If its making game sounds.......its worth saving.

[mkd3b]

Thats what Im talkin About, Jay your the Man. Thanks for The support and Words of Encouragement
Ok Now what to do with this shit monitor That I managed to mangle.

[jay]

Staples here in Canada takes any TV, Monitor, computer (any electronic device) for recyling. They have a big bin instore that we just drop things into. I imagine they would be the same in the US. Simply call them.

[badbaud]

You could set it up as a video game for blind people. I fixed a Galaga game for my brother a while ago - it was a board problem not a monitor problem - and he set it up at his in-laws ice cream shop, damn thing makes over $20 a day in quarters. I agree with Jay, if it has game sounds it is worth the time and effort to get it going.

[mkd3b]

Can anyone give me a heads up as to what else I could use in place of the G07  as I try to find a replacement monitor for this centipede.  Also I looked at a couple of sites for monitors but cant tell If the are monitors only or if they generally are board complete for plug and play application.  The chassis board on the G07 I had already has issues to start with.   Damn I am really pissed off at myself for messing up this tube from being careless, turning a possible cheap easy fix into a pain in the ass.   ArtD

[mkd3b]

Back in business found a replaceent monitor finnally but had to travel 80 miles worth the trip Now have a wells gardner in and the Centipede has been brought to life .  Now I can focus on restoring the Cabinet and art work.  Love these old machines