Low GI

[mildflame]

I am havig a problem with my GI on a SEGA as it only has 3.2V AC at globes. Heave replaced fuse holders and fuses, Connecters, headers have been replaced, Direct from transformer is 7.2 and 2.2 AC. as the powere reaches the power supply board is is reduced to 3.2 and 1.9 AC. connector between ps board and transformer looks ok. Does anyone know where i may be losing my voltage or where i may be heading. PS. I have looked over the wiring diagrams.
HELP! :(

[MartyJ]

Had a similar problem a while back, was definitely related to IDC connectors....

Beaky has just done a write up on rebuilding PSU for SEGA's....Might pay to PM him.

[mildflame]

IDC Connectors have been replaced with TRI Furcon and soldered also.

[beaky]

IDC Connectors have been replaced with TRI Furcon and soldered also.

what is the name of the pin as the early sega's used data east boards in them?

[mildflame]

Frankenstien (same as Brett)

[mildflame]

I also have a Data East Lethal Weapon 3 with same problem

[beaky]

have you checked the g.i. plug at the transformer?
if this plug is ok then and there is a low voltage on the input plug on the power supply you might have a short somewhere dragging the voltage down. check the 4 pin plug on the power supply top right corner, its the one with the wires soldered to the board see what voltage you have there.

[mildflame]

at the transformer connector the voltage was 7.2V AC and 2.2.
At the PS Board it was 3.2 and 1.9

[beaky]

the 7.5 is ok at the transformer end but 2.2 is a worry. They should both be at about the same voltage at the transformer end and at the power supply G.I. input. The G.I circuit comes out of the transformer on 4 wires and goes into the power supply as 4. But the first thing that happens on the power supply board is both yellow wires connect together and the 2 white wires connect together. The yellow goes through the relay on the pwr supply board then goes out on CN8 pins 1 to 4 to the G.I. lamps. The 2 white wires go straight to CN8 on the pwr supp board pins 6 to 9, then to the fuses on the PPB board.

I would like you to look at the attached picture and let me know the voltages between the following wires .
Y1 & W1
Y2 & W2
Y3 & W3
Y4 & W4.
Next I would lke you to unplug CN9 at the power supply. (with the machine turned off) and test the above again.

Once I know these voltages then i will give you some more instructions
 

[mildflame]

the 7.5 is ok at the transformer end but 2.2 is a worry. They should both be at about the same voltage at the transformer end and at the power supply G.I. input. The G.I circuit comes out of the transformer on 4 wires and goes into the power supply as 4. But the first thing that happens on the power supply board is both yellow wires connect together and the 2 white wires connect together. The yellow goes through the relay on the pwr supply board then goes out on CN8 pins 1 to 4 to the G.I. lamps. The 2 white wires go straight to CN8 on the pwr supp board pins 6 to 9, then to the fuses on the PPB board.

I would like you to look at the attached picture and let me know the voltages between the following wires .
Y1 & W1
Y2 & W2
Y3 & W3
Y4 & W4.
Next I would lke you to unplug CN9 at the power supply. (with the machine turned off) and test the above again.

Once I know these voltages then i will give you some more instructions
 

ok,  all measure 6.5V AC ( I was previously measuring to ground each wire)

[Caveoftreasures]

The best thing to do is to have the power supply upgraded by having the caps n various other bits n pieces renewed like i did on my FRANKENSTEIN.
* Without even using a multi-meter, after 15 years plus of machine usage, i can guarrantee that it will be low on the voltage side of things. Check all connectors/pins on the GI side of things as well.

I know this sounds silly, but make sure all the bulbs are 44's and not low light 47's. Check all the 555's by comparing them to new 555's.
NOTE -The globes i buy from Mark C (PSP) are the best quality/brightest i have found. I recently swapped out all the bulbs on my Teenage Mutant Ninja Turtles , and Marks bulbs were so much brighter than the others i had previously purchased elsewhere. I dont know what brand Mark uses, but they are the brightest. Some of the others around are dull compared to the last batch i purchased and was very happy with.

Re the power supply, If u cant rebuild it yourself, wrap it well in bubble wrap, post it to Beaky, and have it made like new. It cost me apx $20 in parts. I am sure Beaky would conduct the work for next to nicks. PM Beaky or me if u want it overhauled.  

[studley67]

thanks for the advice brett,i think we are getting close now to solving it.transformer is good.the cn8 has its wires soldered to the board(euro hack)will now cut them so i can remove board and investigate further,tommorow.i will await approval from andrew,cn8 needs a new header,and connector,i have these parts on hand.i will update tommorow,damien

[studley67]

i plan to crimp the trifurcon pins to the wires and solder for good measure.

[beaky]

We know now you have the correct voltage up to the power supply. Next you need to check how much voltage we are loosing through the pwr supply board and the PPB board.
 it is normal to lose around out 0.5 between the G.I Input plug on the power supply & the G.I out puts (one on the power supply and the other om the PPB board).

check the voltage at the G.I. input on the Pwr supply board.

CN9 Y3 & W3
CN9 Y4 & W4

Next check the G.I. voltage coming out of the power supply
CN8 Pin 1 (Brown) &  pin 6 (white / Brown)

Next check the G.I voltage out put on the power supply and PPB board
Pwr sup: CN8 Pin 1 (Brown)   & PPB J5 Pin 5 (white / Brown)
Pwr sup: CN8 Pin 2 (yellow)  & PPB J5 Pin 6 (white / YELLOW)
Pwr sup: CN8 pIN 3 (Green)   & PPB J5 Pin 7 (white / Green)
Pwr sup: CN8 pIN 4 (violet)  & PPB J5 Pin 9 (white / violet)

Again after I get these I will give you more instruction.

Just so you know i am trying to find out where the weak spots are that are causing the problem. It is a good idea to change the CN8 on the power supply. It maybe the plug you are changing or the tracks to and from the relay on the power supply board. or the plug for the fuses on the ppb. Also check the fuse clips on the ppp board. these fuse clips are know for thier cracking.
sorry it took so long to reply tonight.

[beaky]

I know this sounds silly, but make sure all the bulbs are 44's and not low light 47's. Check all the 555's by comparing them to new 555's.
NOTE -The globes i buy from Mark C (PSP) are the best quality/brightest i have found. I recently swapped out all the bulbs on my Teenage Mutant Ninja Turtles , and Marks bulbs were so much brighter than the others i had previously purchased elsewhere. I dont know what brand Mark uses, but they are the brightest. Some of the others around are dull compared to the last batch i purchased and was very happy with.

Brett is correct about the lamps. the lamps that came with his TMNT where the worst lamps i have seen. just changing the lamps mad a huge difference.