tech,,taxi system 11 power supply

[Guest]

Archived from groups: rec.games.pinball (More info?)

I just picked up a taxi machine at auction , the machine tech at the
place told me last time he plugged the machine in that it worked but
the display didn't come up,,,, well,,,, the only thing that comes up
are the GI lights.

I started poking around with my finger,, checking fuses and such and
the side of my hand touched the heat sink on the Q3 transistor and I
got a pretty good little jolt!!!

I checked voltages at all test points and they were all very low, I'm
going to replace all the elecrto caps for sure due to age but the
getting zapped thing has me a bit puzzled,,,,is that normal??? I have a
bunch of other machines and I've never got nailed from a heat sink!

Also,,, the 3 diagnostic LED's the the cpu do nothing,,,,obviously due
to the low voltage,,,,, I guess the questions is could this whole power
supply go bad? or is there something else that caused it to go out. Oh
yeah,,, the fuse at F3 was blown.

Any help would be appreciated
Thanks,
Shanda

 

[Guest]

Archived from groups: rec.games.pinball (More info?)

Never good practice to touch ANY of those
you come accross. Use a meter.

Early Chrysler electronic ignition modules, for
example, could near send you flying across the
shop if you did that!

--
Fred
TX
CARGPB#8
******************




"Shanda" <shandatg@aol.com> wrote

> I started poking around with my finger,, checking fuses and such and
> the side of my hand touched the heat sink on the Q3 transistor and I
> got a pretty good little jolt!!!

 

[Guest]

Archived from groups: rec.games.pinball (More info?)

>>I started poking around with my finger,, checking fuses and such and
>>the side of my hand touched the heat sink on the Q3 transistor and I
>>got a pretty good little jolt!!!

Looks like the -100V circuit is bad. I would disconnect the display unit and check
if the cpu boots. Something might have toasted the Master Display.

>>I checked voltages at all test points and they were all very low, I'm
>>going to replace all the elecrto caps for sure due to age

Usually not necessary. Taxi is too new and they are usually still ok. I would
first try to isolate the problem before working on the board.

>> but the
>>getting zapped thing has me a bit puzzled,,,,is that normal??? I have a
>>bunch of other machines and I've never got nailed from a heat sink!

Bad H/V circuit.

>>Also,,, the 3 diagnostic LED's the the cpu do nothing,,,,obviously due
>>to the low voltage,,,,, I guess the questions is could this whole power
>>supply go bad? or is there something else that caused it to go out. Oh
>>yeah,,, the fuse at F3 was blown.

F3 is for Q3.

>>Any help would be appreciated

First pull F1. It's the main fuse for the display voltages. Then Check the AC
voltages from the transformer to the PS before and after F4 and F5 If they are
good check the DC voltages behind the bridge. Might be a bad bridge. If ok work
upward. the Sorcerer manual on the ipdb describes additional test points.
Different board but identical circuit.

Regards
Frank-Rainer Grahl
(frgrahl@REMOVE.ME.gmx.net)