Sinbad
Gottlieb, 1978I finally made it back to working on my Sinbad pinball. I was looking at the voltages on the A2P1 connector that feeds the bottom panel power to the power supply. Here is the break out.
Pin1 11.77v
pin2 11.78v
pin3 gnd
pin4 14.17v
pin5 4.32v
pin6 70v
pin7 70v
Looking at the schematic pin5 should be 14v. Does this mean I need a new large transformer? I have check all the fuses and the bridge rectifiers as well and they all look good.
Thanks for the help.
Those values come from the small transformer. But the fact you have values makes it seem like the transformer is fine. The best things to check are the fuse clips and crimps on that connector. I had a low value on a system 80 due to a tarnished loose fuse clip
Could also be a bridge is failing on one side.
here's a checklist for testing from the bottom board to the power supply
https://docs.google.com/spreadsheets/d/1NV3NaXS6d696csiFSRcvi900dFwyPZSgFZfkDUwaZ4U/edit?usp=sharing
Made a little progress.
A2J1 connector (Sorry I said A2P1 and I was wrong)
Pins 1-5 come straight off the small transformer with no fuse or bridge.
Pins 6-7 use fuse 69V 1/2 slow blow.
I pulled all the fuses except the main power fuse and tested to see if I was still getting voltage to pins 1-5 and yes they are the same as above. Pin 6-7 of course was not giving proper voltage since I pulled the fuse. After putting the fuse for the 69V it tested good.
First question what am I missing or doing wrong and can a transformer go out on just one leg?
second does anyone have a test guide for testing the small transformer?
Thanks!
refreshed my memory with the schematic, yeah only 1 fuse.
These voltages coming to A2J1 are all AC. You can measure from
Red 1, Black 3 ~14VAC
Red 2, Black 3 ~12VAC
Red 4, Black 3 ~12VAC
Red 5, Black 3 ~14VAC
Or you can measure from 1 to 5 ~28VAC and 2 to 3 ~24VAC.
Ideally you can measure these voltages straight off the small transformer since there's nothing in the way except the fuse on A2J1-6.
For the transformer measure from 3 to 7 ~28VAC and 4 to 6 ~24VAC. Or you can measure each to #5 for half of the value. Note some may be negative depending on the direction you measure.
Usually a bad transformer has some evidence of damage. When you get the the values you need make sure and protect this hard to find small transformer thusly: http://www.pinwiki.com/wiki/index.php?title=Gottlieb_System_1#Recommended_Fuses_to_Install_to_Protect_the_Small_Transformer
pasted_image (resized).pngYes sir same as the connector A2J1-5. If I test straight at the transformer I am getting 4.35 on 3 and 14.17 on 7. Its just that one leg of the transformer that is reading bad.
I have been reading and it sounds like their is no real good replacement. I do have a px1-4 board for this system but without the small transformer it sounds like no one has a real work around.
this one might be good: https://pinside.com/pinball/market/classifieds/ad/81628
another https://pinside.com/pinball/market/classifieds/ad/80458
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New Braunfels, TX