Taito Trimline Power Problem - No 12v

Raikus

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Finally got around to testing my Taito Space Invaders Trimline cabinet (since I got the board stack in). I'm getting good readings on my +5v and -5v in the harness, but no 12v readings at all.

I've searched but there doesn't seem to be much troubleshooting on Trimline power supplies. I'm not sure where to start on the power board (first time with Taito). Anyone have some advice to help me start tracking it down?
 
There's a power supply schematic floating around on the internet somewhere. I saved it one time, when I came across it, but I'm not sure where it is. I'll see if I can dig it up.
 
Thanks for jogging my memory. Here's the diagram I found in another thread:

TrimlinePSschematicmodified.jpg


Ok, with that I started nosing around and found a problem. Fixed and now I'm getting 11.6v from the power board. On power up I'm seeing very faint wavy horizontal lines but no playing game that I can discern. Would 11.6v be close enough to power the PCB stack correctly or does it need to be 12v exactly? Off to try and find a PCB schematic now.
 
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11.6VDC should be fine. Check for bad connectors, or cracked header pins....these could cause some voltage drop. Also, dried out capacitors can start to drag down voltage.

Edward
 
Ok, with that I started nosing around and found a problem. Fixed and now I'm getting 11.6v from the power board. On power up I'm seeing very faint wavy horizontal lines but no playing game that I can discern. Would 11.6v be close enough to power the PCB stack correctly or does it need to be 12v exactly? Off to try and find a PCB schematic now.

Wouldn't the 12V be for sound?
I would imagine, if the PCB stack was good to go, and you had 5V you would have the video of the game.
Does it coin up ... now that you are close to 12V (if it IS for sound) you should hear game sounds if it was starting up... right?
 
Wouldn't the 12V be for sound?
I would imagine, if the PCB stack was good to go, and you had 5V you would have the video of the game.
Does it coin up ... now that you are close to 12V (if it IS for sound) you should hear game sounds if it was starting up... right?

On Space Invaders, RAM also use 12VDC.......and depending on what type of ROMs....they could also use 12VDC.

Edward
 
Does it coin up ... now that you are close to 12V (if it IS for sound) you should hear game sounds if it was starting up... right?

The harness voltages check out correctly now, but it's still not displaying anything. Monitor works (as far as glow) and the coin counter clicks when the coin switch is toggled. I don't believe there's any light indicator on the PCB stack to help out.

I guess there's something wrong with the PCB (it was untested and the only one I could get my hands on) but I don't know where to start with it. Can't seem to find any information on the Trimline board stack as far as testing goes -- or a schematic outside of the components listed in the manual.
 
If there's 12V Ram on that board, you are going to have timing out of whack if your 12v line is at 11.6. I'd head through your boardstack and PSU with an ESR meter to rule out bad Electrolytics, then try and adjust your PSU up to atleast 11.9/12.1v.
 
Ok, all 12v to harness now 12.0. Same with +5 and -5. Still nothing. Don't have an ESR meter though to check out the caps.

Nothing at all? Screen has no garbage on it or anything?
Wow... I'm gonna be no help.
My broken stacks all make garbage on the screen at least.

Isn't there some sort of funky reset line for the power that has to be hooked up/working on these?
 
Yeah, nothing :(

I guess that may be an indicator though. I'll take a look at the video signal feed and double check to make sure everything is hooked up properly.
 
Couldn't determine anything wrong with the video signal. Checked monitor board and everything looks intact, plugged in correctly, etc. The posts do what they're supposed to it's just that there's no signal coming into the monitor to display.

Guess I'm back to the PCB being bad and not knowing what to look for to fix it :(
 
The other thing to check is that the PCB's have been assembled in the correct order.....lay them all flat component side up and plug together(processor board in the middle), I've seen a few dead sets that have had one PCB upside down, It's easy to do.
 
It would be a good idea to check the reset line to the PCB, without it the game won't boot. Do you have anyway to check for a clock signal on the PCB? logic probe?

Thanks! I'll do that when I get home tonight.

The PCB set is laid out correctly (something I had checked when I installed it).
 
Ok, figured out the issue. The old power board wasn't sending the reset signal to the board. I found a new board that works and now everything but the sound works... but it game is playing in horizontal orientation instead of vertical. Whiskey Tango Foxtrot?!

Any ideas? I've looked over the monitor board and there's no way to seemingly "flip" it over to vertical. Once I figure out the orientation issue I can focus on the sound.
 
I found a new board that works...

Any suggestions on where I should look for a new board?

When you were checking voltages, was your PS connected to the stack? My board is squeeling like crazy and then blowing fuse F5 (6A). Can i test this without a load, or does it need to be connected to the harness?

thanks for any ideas,
John
 
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Ok, figured out the issue. The old power board wasn't sending the reset signal to the board. I found a new board that works and now everything but the sound works... but it game is playing in horizontal orientation instead of vertical. Whiskey Tango Foxtrot?!

Any ideas? I've looked over the monitor board and there's no way to seemingly "flip" it over to vertical. Once I figure out the orientation issue I can focus on the sound.

have you got the 4 wires from the Yoke on the back of the tube, where they plug into the monitor PCB around the wrong way?
 
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