Taito Power Supply schematic needed....

[modessitt]

Trying to fix a Taito Trimline Space Invaders cabaret. +5 is fluctuating between +9 and +11. I get a steady buzz under load, and a recurring buzz when disconnected from the board.

Can't find a schematic for the PS anywhere. I've seen it was mentioned in various Taito manuals from 79-80 games, but none have the PS schematic.

If anyone can point me at one, I'd appreciate it.

This is the PS I am talking about:

 

[ElfShotTheFood]

I have a hard copy of all the SI trimline schematics. I can probably scan it for you tomorrow.



EDIT; I tried taking a high res pic, but it was too fuzzy to read.

 

[modessitt]

Lemme know. I looked through the Trimline schematics online, and they had every board EXCEPT the power supply...

 

[ThurworAlpha]

Taito power supply

That is the same power supply used in my cocktail Stratovox game... try some of the cocktail game manuals. Unfortunately, I do not have the power supply schematic in my manual either. Please let me know if you find it!

Kenneth

 

[ElfShotTheFood]

here you go.

I don't know how to stitch together two scans, so I just scanned the schematic that was in the center of a mostly blank double page. all the good info is there, just without the border around the drawing and the little box that doesn't have any useful info.


edit; "Your file of 168.0 KB bytes exceeds the forum's limit of 19.5 KB for this filetype." damn.
edit2; emailed to ya.

 

[modessitt]

Thanks ESTF. I guess you sent it to my JR email? I'll check when I get home.

That is the same power supply used in my cocktail Stratovox game... try some of the cocktail game manuals. Unfortunately, I do not have the power supply schematic in my manual either. Please let me know if you find it!

Kenneth

Yeah, I checked a bunch of Taito manuals (including Stratovox) before posting here. Unfortunately, all just give a casual mention of it, or show where the adjustments are, but don't include a schematic.

I'll check this one ESTF sent, and post it if it turns out to be the right one....

 

[KenLayton]

The Taito Trimline Space Invaders manual does show a pinout of the power supply.

It puts out +5, -5, +12, -12, Gnd, and has a reset signal to the cpu board.

 

[Lindsey]

Is anything getting hot? Maybe the voltage regulator is crapping out?

 

[ElfShotTheFood]

I can send it again to a different addresss if you need it sooner.

where are all the other trimline schematics posted? I'll check and see if there are any others I have that aren't online.

 

[modessitt]

The Trimline manual is available on Xmission and a few other places. Brentradio has a bunch of Taito SI stuff, too, including Trimline docs. But none had the PS schematic....

 

[modessitt]

The Taito Trimline Space Invaders manual does show a pinout of the power supply.

It puts out +5, -5, +12, -12, Gnd, and has a reset signal to the cpu board.

Yeah, I saw that, which is how I figured out my +12 was so high and was pulsing between +10.6 and +12.2

If it wasn't for that Reset signal, I'd probably just pop a new PS in it...

 

[modessitt]

Is anything getting hot? Maybe the voltage regulator is crapping out?

Nothing's getting hot that isn't already attached to a heat sink. I thought about the VR, but there may be several. All of them are reading fine under diode test, but I need to track the schematic to see what voltages I should be expecting where....

 

[ElfShotTheFood]

I don't see the schematic for the trimline monitor, hitachi k14c-5080 anywhere.

unless I haven't looked in the right spot yet.

 

[modessitt]

Here is the schematic sent to me from ESTF. Thanks, Ben...

 

[modessitt]

UPDATE:

I did some tracing and found some issues with the C945 transistor at Q8. Replaced it, and my +5 is no longer fluctuating between 10.6 and 12.3. It is now holding steady at +7.12. I figured it might be doing that because there was no load attached, so I stuck it back in the cab, and found it to still be +7.12. Adjusting the +5 pot does nothing (pot is ok).

Now, if you check that schematic above, I have verified the voltage is high BEFORE the fuse at F5, since removing does nothing. I also checked across the outer windings of the output of T3, and supposedly have +5.0 (although I'm not sure I'm reading it in the right way).

Am I going to need to replace all those 2200uF caps between T3 and the fuse?

 

[KenLayton]

If the electrolytic caps go open or down in value, the DC output voltage would go down while AC ripple would go up.

Check/replace IC2 and D24.

 

[modessitt]

If the electrolytic caps go open or down in value, the DC output voltage would go down while AC ripple would go up.

Check/replace IC2 and D24.

Good point. Yeah, I was thinking about IC2, but it'll have to wait until tomorrow now...

 

[armi0024]

just an FYI, mine was doing the same thing, had enough projects to do so I bought one from tntamusements. I did have to replace a zener on the tnt amusement one but in retrospect that may have been my fault.

 

[armi0024]

btw this is exactly why we need a wiki arcade....

 

[modessitt]

Okay, I don't want to spend too much time on this, and since it's going into a commercial location, I think a newer PS would be a better bet for long-term stability.

I'm worried about the RESET signal coming from the PS. Looking at the schematic, it appears to be generated by IC3 as a result of the +5 signal being detected at the proper levels. With that the case, could I make trace cuts where I've marked the green lines in the schematic below, then attach the +5 at the red dot and GND at the black dot - and make it work as intended? All my other voltages are present as indicated.